APIs / VMODs

• WS_Reserve() is now deprecated and any use should trigger a compiler warning. It is to be replaced by

  • WS_ReserveAll() to reserve all of the remaining workspace

    It will always leave the workspace reserved even if 0 bytes are available, so it must always be followed by a call to WS_Release()

  • WS_ReserveSize() to reserve a fixed amount.

    It will only leave the workspace reserved if the reservation request could be fulfilled.

  We provide a script to help automate this change in the tools/coccinelle subdirectory of the source tree.

• The RST references generated by vmodtool.py have been changed to match better the VCL syntax to avoid overhead where references are used. The new scheme for a vmod called name is:

  • $Function: name.function()
  • $Object constructor: name.object()
  • $Method: xobject.method()

  To illustrate, the old references:

  :ref:`vmod_name.function`
  :ref:`vmod_name.obj`
  :ref:`vmod_name.obj.method`
  

  now are renamed to:

  :ref:`name.function()`
  :ref:`name.obj()`
  :ref:`xobj.method()`
  

  tools/vmod_ref_rename.sh is provided to automate this task

VCL

• Added req.is_hitmiss and req.is_hitpass (2743)

bundled vmods

• Added directors.lookup()

bundled tools

• Improved varnish log client performance (2788)

• For varnishtest -L, also keep VCL C source files

• Add param.reset command to varnishadm

• Add VSL rate limiting (2837)

  This adds rate limiting to varnishncsa and varnishlog.

• Make it possible to change varnishstat update rate. (2741)

C APIs (for vmod and utility authors)

• libvarnish: VRT_VSA_GetPtr renamed to VSA_GetPtr

• Included vtree.h in the distribution for vmods and renamed the red/black tree macros from VRB_* to VRBT_* to disambiguate from the acronym for Varnish Request Body.

  Changed the internal organisation of dynamic PRIVs (PRIV_TASK, PRIV_TOP from a list to a red/black tree) for performance. (2813)

• Vmod developers are advised that anything returned by a vmod function/method is assumed to be immutable. In other words, a vmod must not modify any data which was previously returned.

• Tolerate null IP addresses for ACL matches.

• Added vstrerror() as a safe wrapper for strerror() to avoid a NULL pointer dereference under rare conditions where the latter could return NULL. (2815)

• Varnish-based tools using the VUT interface should now consider using the VUT_Usage() function for consistency

• The name of the event_function callback for VCL events in vmods is now prefixed by $Prefix_` if $Prefix is defined in the .vcc file, or vmod_ by default.

  So, for example, with $Event foo and no $Prefix, the event function will be called vmod_foo and with $Prefix bar it will be called bar_foo.

• In the vmodtool-generated ReStructuredText documentation, anchors have been renamed

  • from obj_class to vmodname.class for constructors and
  • from func_class to vmodname.function for functions and
  • from func_class to vmodname.class.method for methods,

  repsectively. In short, the anchor is now named equal to VCL syntax for constructors and functions and similarly to VCL syntax for methods.

• VRT API has been updated to 9.0

  • HTTP_Copy() was removed, HTTP_Dup() and HTTP_Clone() were added

  • Previously, VCL_BLOB was implemented as struct vmod_priv, which had the following shortcomings:

    • blobs are immutable, but that was not reflected by the priv pointer
    • the existence of a free pointer suggested automatic memory management, which did never and will not exist for blobs.

    The VCL_BLOB type is now implemented as struct vrt_blob, with the blob member replacing the former priv pointer and the free pointer removed.

    A type member was added for lightweight type checking similar to the miniobject magic member, but in contrast to it, type should never be asserted upon.

    VRT_blob() was updated accordingly.

  • req->req_bodybytes was removed. Replacement code snippet:

    AZ(ObjGetU64(req->wrk, req->body_oc, OA_LEN, &u));
    

  • VRT_SetHealth() has been removed and VRT_SetChanged() added. VRT_LookupDirector() (only to be called from CLI contexts) as been added.

    See release notes for details

• vmodtool has been changed significantly to avoid various name clashes. Rather than using literal prefixes/suffixes, vmod authors should now (and might have to for making existing code continue to compile) use the following macros

  • VPFX(name) to prepend the vmod prefix (vmod_ by default)

  • VARGS(name) as the name of a function/method's argument struct, e.g.:

    VCL_VOID vmod_test(VRT_CTX, struct VARGS(test) *args) { ...
    

  • VENUM(name) to access the enum by the name name

Fixed bugs

• Fixed varnishhist display error (2780)
• Fix varnishstat -f in curses mode (interactively, without -1, 2787)
• Handle an out-of-workspace condition in HTTP/2 delivery more gracefully (2589)
• Fixed regression introduced just before 6.1.0 release which caused an unnecessary incompatibility with VSL files written by previous versions. (2790)
• Fix warmup/rampup of the shard director (2823)
• Fix VRT_priv_task for calls from vcl_pipe {} (2820)
• Fix assinging <bool> == <bool> (2809)
• Fix vmod object constructor documentation in the vmodtool.py - generated RST files
• Fix some stats metrics (vsc) which were wrongly marked as _gauge_
• Fix varnishd -I (2782)
• Add error handling for STV_NewObject() (2831)
• Fix VRT_fail for 'if'/'elseif' conditional expressions (2840)

VCL

• return(fail("mumble")) can have a string argument that is emitted by VCC as an error message if the VCL load fails due to the return. (2694)
• Improved VCC error messages (2696)
• Fixed obj.hits in vcl_hit (had been always 0) (2746)

bundled tools

• varnishhist: Improved test coverage
• varnishtest: Added haproxy CLI send/expect facility

C APIs (for vmod and utility authors)

• libvarnishapi so version bumped to 2.0.0 (2718)
• For VMOD methods/functions with PRIV_TASK or PRIV_TOP arguments, the struct vrt_priv is allocated on the appropriate workspace. In the out-of-workspace condition, VCL failure is invoked, and the VMOD method/function is not called. (2708)
• Improved support for the VCL STRANDS type, VMOD blob refactored to use STRANDS (2745)

Fixed bugs

• A series of bug fixes related to excessive object accumulation and Transient storage use in the hit-for-miss case (2760, 2754, 2654, 2763)
• A series of fixes related to Python and the vmodtool (2761, 2759, 2742)
• UB in varnishhist (2773)
• Allow to not have randomness in file_id (2436)
• b64.vtc unstable (2753)
• VCL_Poll ctx scope (2749)

varnishstat

• The counters

  • sess_fail_econnaborted
  • sess_fail_eintr
  • sess_fail_emfile
  • sess_fail_ebadf
  • sess_fail_enomem
  • sess_fail_other

  now break down the detailed reason for session accept failures, the sum of which continues to be counted in sess_fail.

VCL and bundled VMODs

• VMOD unix now supports the getpeerucred(3) case.

bundled tools

• varnishhist: The format of the -P argument has been changed for custom profile definitions to also contain a prefix to match the tag against.
• varnishtest: syslog instances now have to start with a capital S.

Fixed bugs which may influence VCL behavior

• When an object is out of grace but in keep, the client context goes straight to vcl_miss instead of vcl_hit. The documentation has been updated accordingly. (2705)

Fixed bugs

• Several H2 bugs (2285, 2572, 2623, 2624, 2679, 2690, 2693)
• Make large integers work in VCL. (2603)
• Print usage on unknown or missing arguments (2608)
• Assert error in VPX_Send_Proxy() with proxy backends in pipe mode (2613)
• Holddown times for certain backend connection errors (2622)
• Enforce Host requirement for HTTP/1.1 requests (2631)
• Introduction of '-' CLI prefix allowed empty commands to sneak through. (2647)
• VUT apps can be stopped cleanly via vtc process -stop (2649, 2650)
• VUT apps fail gracefully when removing a PID file fails
• varnishd startup log should mention version (2661)
• In curses mode, always filter in the counters necessary for the header lines. (2678)
• Assert error in ban_lurker_getfirst() (2681)
• Missing command entries in varnishadm help menu (2682)
• Handle string literal concatenation correctly (2685)
• varnishtop -1 does not work as documented (2686)
• Handle sigbus like sigsegv (2693)
• Panic on return (retry) of a conditional fetch (2700)
• Wrong turn at cache/cache_backend_probe.c:255: Unknown family (2702, 2726)
• VCL failure causes TASK_PRIV reference on reset workspace (2706)
• Accurate ban statistics except for a few remaining corner cases (2716)
• Assert error in vca_make_session() (2719)
• Assert error in vca_tcp_opt_set() (2722)
• VCL compiling error on parenthesis (2727)
• Assert error in HTC_RxPipeline() (2731)

Usage

• Fixed implementation of the max_restarts limit: It used to be one less than the number of allowed restarts, it now is the number of return(restart) calls per request.

• The cli_buffer parameter has been removed

• Added back umem storage for Solaris descendants

• The new storage backend type (stevedore) default now resolves to either umem (where available) or malloc.

• Since varnish 4.1, the thread workspace as configured by workspace_thread was not used as documented, delivery also used the client workspace.

  We are now taking delivery IO vectors from the thread workspace, so the parameter documentation is in sync with reality again.

  Users who need to minimize memory footprint might consider decreasing workspace_client by workspace_thread.

• The new parameter esi_iovs configures the amount of IO vectors used during ESI delivery. It should not be tuned unless advised by a developer.

• Support Unix domain sockets for the -a and -b command-line arguments, and for backend declarations. This requires VCL >= 4.1.

VCL and bundled VMODs

• return (fetch) is no longer allowed in vcl_hit {}, use return (miss) instead. Note that return (fetch) has been deprecated since 4.0.

• Fix behaviour of restarts to how it was originally intended: Restarts now leave all the request properties in place except for req.restarts and req.xid, which need to change by design.

• req.storage, req.hash_ignore_busy and req.hash_always_miss are now accessible from all of the client side subs, not just vcl_recv{}

• obj.storage is now available in vcl_hit{} and vcl_deliver{}.

• Removed beresp.storage_hint for VCL 4.1 (was deprecated since Varnish 5.1)

  For VCL 4.0, compatibility is preserved, but the implementation is changed slightly: beresp.storage_hint is now referring to the same internal data structure as beresp.storage.

  In particular, it was previously possible to set beresp.storage_hint to an invalid storage name and later retrieve it back. Doing so will now yield the last successfully set stevedore or the undefined (NULL) string.

• IP-valued elements of VCL are equivalent to 0.0.0.0:0 when the connection in question was addressed as a UDS. This is implemented with the bogo_ip in vsa.c.

• beresp.backend.ip is retired as of VCL 4.1.

• workspace overflows in std.log() now trigger a VCL failure.

• workspace overflows in std.syslog() are ignored.

• added return(restart) from vcl_recv{}.

• The alg argument of the shard director .reconfigure() method has been removed - the consistent hashing ring is now always generated using the last 32 bits of a SHA256 hash of "ident%d" as with alg=SHA256 or the default.

  We believe that the other algorithms did not yield sufficiently dispersed placement of backends on the consistent hashing ring and thus retire this option without replacement.

  Users of .reconfigure(alg=CRC32) or .reconfigure(alg=RS) be advised that when upgrading and removing the alg argument, consistent hashing values for all backends will change once and only once.

• The alg argument of the shard director .key() method has been removed - it now always hashes its arguments using SHA256 and returns the last 32 bits for use as a shard key.

  Backwards compatibility is provided through vmod blobdigest with the key_blob argument of the shard director .backend() method:

  • for alg=CRC32, replace:

    <dir>.backend(by=KEY, key=<dir>.key(<string>, CRC32))
    

    with:

    <dir>.backend(by=BLOB, key_blob=blobdigest.hash(ICRC32,
      blob.decode(encoded=<string>)))
    

    Note: The vmod blobdigest hash method corresponding to the shard director CRC32 method is called ICRC32

• for alg=RS, replace:

  <dir>.backend(by=KEY, key=<dir>.key(<string>, RS))
  

  with:

  <dir>.backend(by=BLOB, key_blob=blobdigest.hash(RS,
    blob.decode(encoded=<string>)))
  

• The shard director now offers resolution at the time the actual backend connection is made, which is how all other bundled directors work as well: With the resolve=LAZY argument, other shard parameters are saved for later reference and a director object is returned.

  This enables layering the shard director below other directors.

• The shard director now also supports getting other parameters from a parameter set object: Rather than passing the required parameters with each .backend() call, an object can be associated with a shard director defining the parameters. The association can be changed in vcl_backend_fetch() and individual parameters can be overridden in each .backend() call.

  The main use case is to segregate shard parameters from director selection: By associating a parameter object with many directors, the same load balancing decision can easily be applied independent of which set of backends is to be used.

• To support parameter overriding, support for positional arguments of the shard director .backend() method had to be removed. In other words, all parameters to the shard director .backend() method now need to be named.

• Integers in VCL are now 64 bits wide across all platforms (implemented as int64_t C type), but due to implementation specifics of the VCL compiler (VCC), integer literals' precision is limited to that of a VCL real (double C type, roughly 53 bits).

  In effect, larger integers are not represented accurately (they get rounded) and may even have their sign changed or trigger a C compiler warning / error.

• Add VMOD unix.

• Add VMOD proxy.

Logging / statistics

• Turned off PROXY protocol debugging by default, can be enabled with the protocol debug flag.
• added cache_hit_grace statistics counter.
• added n_lru_limited counter.
• The byte counters in ReqAcct now show the numbers reported from the operating system rather than what we anticipated to send. This will give more accurate numbers when e.g. the client hung up early without receiving the entire response. Also these counters now show how many bytes was attributed to the body, including any protocol overhead (ie chunked encoding).

bundled tools

• varnishncsa refuses output formats (as defined with the -F command line argument) for tags which could contain control or binary characters. At the time of writing, these are: %{H2RxHdr}x, %{H2RxBody}x, %{H2TxHdr}x, %{H2TxBody}x, %{Debug}x, %{HttpGarbage}x and %{Hash}x
• The vtc server -listen command supports UDS addresses, as does the client -connect command. vtc remote.path and remote.port have the values 0.0.0.0 and 0 when the peer address is UDS. Added remote.path to vtc, whose value is the path when the address is UDS, and NULL (matching <undef>) for IP addresses.

C APIs (for vmod and utility authors)

• We have now defined three API Stability levels: VRT, PACKAGE, SOURCE.
• New API namespace rules, see phk_api_spaces_
• Rules for including API headers have been changed: * many headers can now only be included once * some headers require specific include ordering * only cache.h _or_ vrt.h can be included
• Signatures of functions in the VLU API for bytestream into text serialization have been changed
• vcl.h now contains convenience macros VCL_MET_TASK_B, VCL_MET_TASK_C and VCL_MET_TASK_H for checking ctx->method for backend, client and housekeeping (vcl_init/vcl_fini) task context
• vcc files can now contain a $Prefix stanza to define the prefix for vmod function names (which was fixed to vmod before)
• vcc files can contain a $Synopsis stanza with one of the values auto or manual, default auto. With auto, a more comprehensive SYNOPSIS is generated in the doc output with an overview of objects, methods, functions and their signatures. With manual, the auto-SYNOPSIS is left out, for VMOD authors who prefer to write their own.
• All Varnish internal SHA256* symbols have been renamed to VSHA256*
• libvarnish now has VNUM_duration() to convert from a VCL duration like 4h or 5s
• director health state queries have been merged to VRT_Healthy()
• Renamed macros: * __match_proto__() -> v_matchproto_() * __v_printflike() -> v_printflike_() * __state_variable__() -> v_statevariable_() * __unused -> v_unused_ * __attribute__((__noreturn__) -> v_noreturn_
• ENUMs are now fixed pointers per vcl.
• Added VRT_blob() utility function to create a blob as a copy of some chunk of data on the workspace.
• Directors now have their own admin health information and always need to have the (struct director).admin_health initialized to VDI_AH_* (usually VDI_AH_HEALTHY).

Other changes relevant for VMODs

• PRIV_* function/method arguments are not excluded from auto-generated vmod documentation.

Fixed bugs which may influence VCL behaviour

• After reusing a backend connection fails once, a fresh connection will be opened (2135).

Fixed bugs

• Honor first_byte_timeout for recycled backend connections. (1772)
• Limit backend connection retries to a single retry (2135)
• H2: Move the req-specific PRIV pointers to struct req. (2268)
• H2: Don't panic if we reembark with a request body (2305)
• Clear the objcore attributes flags when (re)initializing an stv object. (2319)
• H2: Fail streams with missing :method or :path. (2351)
• H2: Enforce sequence requirement of header block frames. (2387)
• H2: Hold the sess mutex when evaluating r2->cond. (2434)
• Use the idle read timeout only on empty requests. (2492)
• OH leak in http1_reembark. (2495)
• Fix objcore reference count leak. (2502)
• Close a race between backend probe and vcl.state=Cold by removing the be->vsc under backend mtx. (2505)
• Fail gracefully if shard.backend() is called in housekeeping subs (2506)
• Fix issue #1799 for keep. (2519)
• oc->last_lru as float gives too little precision. (2527)
• H2: Don't HTC_RxStuff with a non-reserved workspace. (2539)
• Various optimizations of VSM. (2430, 2470, 2518, 2535, 2541, 2545, 2546)
• Problems during late socket initialization performed by the Varnish child process can now be reported back to the management process with an error message. (2551)
• Fail if ESI is attempted on partial (206) objects.
• Assert error in ban_mark_completed() - ban lurker edge case. (2556)
• Accurate byte counters (2558). See Logging / statistics above.
• H2: Fix reembark failure handling. (2563 and 2592)
• Working directory permissions insufficient when starting with umask 027. (2570)
• Always use HTTP/1.1 on backend connections for pass & fetch. (2574)
• EPIPE is a documented errno in tcp(7) on linux. (2582)
• H2: Handle failed write(2) in h2_ou_session. (2607)

Bugs fixed

• 2429 - Avoid buffer read overflow on vcl_backend_error and -sfile
• 2492 - Use the idle read timeout only on empty requests.

Usage

• The default for the the -i argument is now the hostname as returned by gethostname(3)
• Where possible (on platforms with setproctitle(3)), the -i argument rather than the -n argument is used for process names
• varnishd -f honors vcl_path (#2342)
• The MAIN.s_req statistic has been removed, as it was identical to MAIN.client_req. VSM consumers should be changed to use the latter if necessary.
• A listen address can take a name in the -a argument. This name is used in the logs and later will possibly be available in VCL.

VCL

• VRT_purge fails a transaction if used outside of vcl_hit and vcl_miss (#2339)
• Added bereq.is_bgfetch which is true for background fetches.
• Added VMOD purge (#2404)
• Added VMOD blob (#2407)

C APIs (for vmod and utility authors)

• The VSM API for accessing the shared memory segment has been totally rewritten. Things should be simpler and more general.
• VSC shared memory layout has changed and the VSC API updated to match it. This paves the way for user defined VSC counters in VMODS and later possibly also in VCL.
• New vmod vtc for advanced varnishtest usage (#2276)

Bugs fixed

• 2379 - Correctly handle bogusly large chunk sizes (VSV00001)

Bugs fixed

• 2251 - varnishapi.pc and varnishconfdir
• 2250 - vrt.h now depends on vdef.h making current vmod fail.
• 2249 - "logexpect -wait" doesn't fail
• 2245 - Varnish doesn't start, if use vmod (vmod_cache dir was permission denied)
• 2241 - VSL fails to get hold of SHM
• 2233 - Crash on "Assert error in WS_Assert(), cache/cache_ws.c line 59"
• 2227 - -C flag broken in HEAD
• 2217 - fix argument processing -C regression
• 2207 - Assert error in V1L_Write()
• 2205 - Strange bug when I set client.ip with another string
• 2203 - unhandled SIGPIPE
• 2200 - Assert error in vev_compact_pfd(), vev.c line 394
• 2197 - ESI parser panic on malformed src URL
• 2190 - varnishncsa: The %r formatter is NOT equivalent to "%m http://%{Host}i%U%q %H"
• 2186 - Assert error in sml_iterator(), storage/storage_simple.c line 263
• 2184 - Cannot subtract a negative number
• 2177 - Clarify interactions between restarts and labels
• 2175 - Backend leak between a top VCL and a label
• 2174 - Cflags overhaul
• 2167 - VCC will not parse a literal negative number where INT is expected
• 2155 - vmodtool removes text following $Event from RST docs
• 2151 - Health probes do not honor a backend's PROXY protocol setting
• 2142 - ip comparison fails
• 2148 - varnishncsa cannot decode Authorization header if the format is incorrect.
• 2143 - Assert error in exp_inbox(), cache/cache_expire.c line 195
• 2134 - Disable Nagle's
• 2129 - stack overflow with >4 level esi
• 2128 - SIGSEGV NULL Pointer in STV__iter()
• 2118 - "varnishstat -f MAIN.sess_conn -1" produces empty output
• 2117 - SES_Close() EBADF / Wait_Enter() wp->fd <= 0
• 2115 - VSM temporary files are not always deleted
• 2110 - [CLI] vcl.inline failures
• 2104 - Assert error in VFP_Open(), cache/cache_fetch_proc.c line 139: Condition((vc->wrk->vsl) != 0) not true
• 2099 - VCC BACKEND/HDR comparison produces duplicate gethdr_s definition
• 2096 - H2 t2002 fail on arm64/arm32
• 2094 - H2 t2000 fail on arm64/arm32
• 2078 - VCL comparison doesn't fold STRING_LIST
• 2052 - d12.vtc flaky when compiling with suncc
• 2042 - Send a 304 response for a just-gone-stale hitpass object when appropriate
• 2041 - Parent process should exit if it fails to start child
• 2035 - varnishd stalls with two consecutive Range requests using HTTP persistent connections
• 2026 - Add restart of poll in read_tmo
• 2021 - vcc "used before defined" check
• 2017 - "%r" field is wrong
• 2016 - confusing vcc error when acl referenced before definition
• 2014 - req.ttl: retire or document+vtc
• 2010 - varnishadm CLI behaving weirdly
• 1991 - Starting varnish on Linux with boot param ipv6.disable=1 fails
• 1988 - Lost req.url gives misleading error
• 1914 - set a custom storage for cache_req_body
• 1899 - varnishadm vcl.inline is overly obscure
• 1874 - clock-step related crash
• 1865 - Panic accessing beresp.backend.ip in vcl_backend_error{}
• 1856 - LostHeader setting req.url to an empty string
• 1834 - WS_Assert(), cache/cache_ws.c line 59
• 1830 - VSL API: "duplicate link" errors in request grouping when vsl_buffer is increased
• 1764 - nuke_limit is not honored
• 1750 - Fail more gracefully on -l >= 4GB
• 1704 - fetch_failed not incremented

Bugs fixed

• 2086 - Ignore H2 upgrades if the feature is not enabled.
• 2054 - Introduce new macros for out-of-tree VMODs
• 2022 - varnishstat -1 -f field inclusion glob doesn't allow VBE backend fields
• 2008 - Panic: Assert error in VBE_Delete()
• 1800 - PRIV_TASK in vcl_init/fini

News for Vmod Authors

• workspace and PRIV_TASK for vcl cli events (init/fini methods)
• PRIV_* now also work for object methods with unchanged scope.

Bugs fixed

• 2337 and 2366 - Both Upgrade and Connection headers are needed for WebSocket now
• 2372 - Fix problem with purging and the n_obj_purged counter
• 2373 - VSC n_vcl, n_vcl_avail, n_vcl_discard are gauge
• 2380 - Correct regexp in examples.
• 2390 - Straighten locking wrt vcl_active
• 2429 - Avoid buffer read overflow on vcl_backend_error and -sfile
• 2492 - Use the idle read timeout only on empty requests

Bugs fixed

• 2379 - Correctly handle bogusly large chunk sizes (VSV00001)

Bugs fixed

• 2321 - Prevent storage backends name collisions

Bugs fixed

• 1764 - Correctly honor nuke_limit parameter
• 2022 - varnishstat -1 -f field inclusion glob doesn't allow VBE backend fields
• 2069 - Health probes fail when HTTP response does not contain reason phrase
• 2118 - "varnishstat -f MAIN.sess_conn -1" produces empty output
• 2219 - Remember to reset workspace
• 2320 - Rework and fix varnishstat counter filtering
• 2329 - Docfix: Only root can jail

Bugs fixed

• 2200 - Dramatically simplify VEV, fix assert in vev.c
• 2216 - Make sure Age is always less than max-age
• 2233 - Correct check when parsing the query string
• 2241 - VSL fails to get hold of SHM
• 2270 - Newly loaded auto VCLs don't get their go_cold timer set
• 2273 - Master cooling problem
• 2275 - If the client workspace is almost, but not quite exhaused, we may not be able to get enough iovec's to do Chunked transmission.
• 2295 - Spinning loop in VBE_Poll causes master to kill child on CLI timeout
• 2301 - Don't attempt to check if varnishd is still running if we have already failed.
• 2313 - Cannot link to varnishapi, symbols missing

Bugs fixed

• 1704 - Reverted the docfix and made the fech_failed counter do what the documentation says it should do
• 1865 - Panic accessing beresp.backend.ip in vcl_backend_error
• 2167 - VCC will not parse a literal negative number where INT is expected
• 2184 - Cannot subtract a negative number

Bugs fixed

• 1704 - (docfix) Clarify description of fetch_failed counter
• 1834 - Panic in workspace exhaustion conditions
• 2106 - 4.1.3: Varnish crashes with "Assert error in CNT_Request(), cache/cache_req_fsm.c line 820"
• 2134 - Disable Nagle's
• 2148 - varnishncsa cannot decode Authorization header if the format is incorrect.
• 2168 - Compare 'bereq.backend' / 'req.backend_hint' myDirector.backend() does not work
• 2178 - 4.1 branch does not compile on FreeBSD
• 2188 - Fix vsm_free (never incremented)
• 2190 - (docfix)varnishncsa: The %r formatter is NOT equivalent to...
• 2197 - ESI parser panic on malformed src URL

Bugs fixed

• 2035 - varnishd stalls with two consecutive Range requests using HTTP persistent connections

Bugs fixed

• 1874 - clock-step related crash
• 1889 - (docfix) What does -p flag for backend.list command means
• 2115 - VSM temporary files are not always deleted
• 2129 - (docfix) stack overflow with >4 level esi

Bugs fixed

• 1830 - VSL API: "duplicate link" errors in request grouping when vsl_buffer is increased
• 2010 - varnishadm CLI behaving weirdly
• 2017 - varnishncsa docfix: "%r" field is wrong
• 2107 - (docfix) HEAD requestes changed to GET

Bugs fixed

• 2027 - Racy backend selection
• 2024 - panic vmod_rr_resolve() round_robin.c line 75 (be) != NULL
• 2011 - VBE.*.conn (concurrent connections to backend) not working as expected
• 2008 - Assert error in VBE_Delete()
• 2007 - Update documentation part about CLI/management port authentication parameter
• 1881 - std.cache_req_body() w/ return(pipe) is broken

Bugs fixed

• 1984 - Make the counter vsm_cooling act according to spec
• 1963 - Avoid abort when changing to a VCL name which is a path
• 1933 - Don't trust dlopen refcounting

Bugs fixed

• 1971 - Add missing Wait_HeapDelete
• 1967 - [ncsa] Remove implicit line feed when using formatfile
• 1955 - 4.1.x sometimes duplicates Age and Accept-Ranges headers
• 1954 - Correctly handle HTTP/1.1 EOF response
• 1953 - Deal with fetch failures in ved_stripgzip
• 1931 - Allow VCL set Last-Modified to be used for I-M-S processing
• 1928 - req->task members must be set in case we get onto the waitinglist
• 1924 - Make std.log() and std.syslog() work from vcl_{init,fini}
• 1919 - Avoid ban lurker panic with empty olist
• 1918 - Correctly handle EOF responses with HTTP/1.1
• 1912 - Fix (insignificant) memory leak with mal-formed ESI directives.
• 1904 - Release memory instead of crashing on malformed ESI
• 1885 - [vmodtool] Method names should start with a period
• 1879 - Correct handling of duplicate headers on IMS header merge
• 1878 - Fix a ESI+gzip corner case which had escaped notice until now
• 1873 - Check for overrun before looking at the next vsm record
• 1871 - Missing error handling code in V1F_Setup_Fetch
• 1869 - Remove temporary directory iff called with -C
• 1883 - Only accept C identifiers as acls
• 1855 - Truncate output if it's wider than 12 chars
• 1806 - One minute delay on return (pipe) and a POST-Request
• 1725 - Revive the backend_conn counter

Bugs fixed

• 1860 - ESI-related memory leaks
• 1863 - Don't reset the oc->ban pointer from BAN_CheckObject
• 1864 - Avoid panic if the lurker is working on a ban to be checked.

Bugs fixed

• 1858 - Hit-for-pass objects are not IMS candidates

Bugs fixed

• 1739 - Workspace overflow handling in VFP_Push()
• 1837 - Error compiling VCL if probe is referenced before it is defined
• 1841 - Replace alien FD's with /dev/null rather than just closing them
• 1843 - Fail HTTP/1.0 POST and PUT requests without Content-Length
• 1844 - Correct ENUM handling in object constructors
• 1851 - Varnish 4.1.1 fails to build on i386
• 1852 - Add a missing VDP flush operation after ESI:includes.
• 1857 - Fix timeout calculation for session herding.

Bugs fixed

• 1802 - Segfault after VCL change
• 1825 - Cannot Start Varnish After Just Restarting The Service
• 1842 - Handle missing waiting list gracefully.
• 1845 - Handle whitespace after floats in test fields

Bugs fixed

• 1796 - Don't attempt to allocate a V1L from the workspace if it is overflowed.
• 1794 - Fail if multiple -a arguments return the same suckaddr.
• 1763 - Restart epoll_wait on EINTR error
• 1788 - ObjIter has terrible performance profile when busyobj != NULL
• 1798 - Varnish requests painfully slow with large files
• 1816 - Use a weak comparison function for If-None-Match
• 1818 - Allow grace-hits on hit-for-pass objects, [..]
• 1821 - Always slim private & pass objects after delivery.
• 1823 - Rush the objheader if there is a waiting list when it is deref'ed.
• 1826 - Ignore 0 Content-Lengths in 204 responses
• 1813 - Fail if multiple -a arguments return the same suckaddr.
• 1810 - Improve handling of HTTP/1.0 clients
• 1807 - Return 500 if we cannot decode the stored object into the resp.*
• 1804 - Log proxy related messages on the session, not on the request.
• 1801 - Relax IP constant parsing

Bugs fixed

• 1777 - Disable speculative Range handling on streaming transactions.
• 1778 - [varnishstat] Cast to integer to prevent negative values messing the statistics
• 1781 - Propagate gzip CRC upwards from nested ESI includes.
• 1783 - Align code with RFC7230 section 3.3.3 which allows POST without a body.

Bugs fixed

• 1462 - Use first/last log entry in varnishncsa.
• 1539 - Avoid panic when expiry thread modifies a candidate object.
• 1637 - Fail the fetch processing if the vep callback failed.
• 1665 - Be more accurate when computing client RX_TIMEOUT.
• 1672 - Do not panic on unsolicited 304 response to non-200 bereq.

Bugs fixed

• 1479 - Fix out-of-tree builds.
• 1566 - Escape VCL string question marks.
• 1616 - Correct header file placement.
• 1620 - Fail miss properly if out of backend threads. (Also 1621)
• 1628 - Avoid dereferencing null in VBO_DerefBusyObj().
• 1629 - Ditch rest of waiting list on failure to reschedule.
• 1660 - Don't attempt range delivery on a synth response

Bugs fixed

• 1378 - Properly escape non-printable characters in varnishncsa.
• 1596 - Delay HSH_Complete() until the storage sanity functions has finished.
• 1506 - Keep Content-Length from backend if we can.
• 1602 - Fix a cornercase related to empty pass objects.
• 1607 - Don't leak reqs on failure to revive from waitinglist.
• 1610 - Update forgotten varnishlog example to 4.0 syntax.
• 1612 - Fix a cornercase related to empty pass objects.
• 1623 - Fix varnishhist -d segfault.
• 1636 - Outdated paragraph in Vary: documentation
• 1638 - Fix panic when retrying a failed backend fetch.
• 1639 - Restore the default SIGSEGV handler during pan_ic
• 1647 - Relax an assertion for the IMS update candidate object.
• 1648 - Avoid partial IMS updates to replace old object.
• 1650 - Collapse multiple X-Forwarded-For headers

Bugs fixed

• 1553 - Fully reset workspace (incl. Vary state) before reusing it.
• 1551 - Handle workspace exhaustion during purge.
• 1591 - Group entries correctly in varnishtop.
• 1592 - Bail out on workspace exhaustion in VRT_IP_string.
• 1538 - Relax VMOD ABI check for release branches.
• 1584 - Don't log garbage/non-HTTP requests. [varnishncsa]
• 1407 - Don't rename VSM file until child has started.
• 1466 - Don't leak request structs on restart after waitinglist.
• 1580 - Output warning if started without -b and -f. [varnishd]
• 1583 - Abort on fatal sandbox errors on Solaris. (Related: 1572)
• 1585 - Handle fatal sandbox errors.
• 1572 - Exit codes have been cleaned up.
• 1569 - Order of symbols should not influence compilation result.
• 1579 - Clean up type inference in VCL.
• 1578 - Don't count Age twice when computing new object TTL.
• 1574 - std.syslog() logged empty strings.
• 1555 - autoconf editline/readline build issue.
• 1568 - Skip NULL arguments when hashing.
• 1567 - Compile on systems without SO_SNDTIMEO/SO_RCVTIMEO.
• 1512 - Changes to bereq are lost between v_b_r and v_b_f.
• 1563 - Increase varnishtest read timeout.
• 1561 - Never call a VDP with zero length unless done.
• 1562 - Fail correctly when rereading a failed client request body.
• 1521 - VCL compilation fails on OSX x86_64.
• 1547 - Panic when increasing shm_reclen.
• 1503 - Document return(retry).
• 1581 - Don't log duplicate Begin records to shmlog.
• 1588 - Correct timestamps on pipelined requests.
• 1575 - Use all director backends when looking for a healthy one.
• 1577 - Read the full request body if shunted to synth.
• 1532 - Use correct VCL representation of reals.
• 1531 - Work around libedit bug in varnishadm.

Bugs fixed

• 1269 - Use correct byte counters in varnishncsa when piping a request.
• 1524 - Chunked requests should be pipe-able.
• 1530 - Expire old object on successful IMS fetch.
• 1475 - time-to-first-byte in varnishncsa was potentially dishonest.
• 1480 - Porting guide for 4.0 is incomplete.
• 1482 - Inherit group memberships of -u specified user.
• 1473 - Fail correctly in configure when rst2man is not found.
• 1486 - Truncate negative Age values to zero.
• 1488 - Don't panic on high request rates.
• 1489 - req.esi should only be available in client threads.
• 1490 - Fix thread leak when reducing number of threads.
• 1491 - Reorder backend connection close procedure to help test cases.
• 1498 - Prefix translated VCL names to avoid name clashes.
• 1499 - Don't leak an objcore when HSH_Lookup returns expired object.
• 1493 - vcl_purge can return synth or restart.
• 1476 - Cope with systems having sys/endian.h and endian.h.
• 1496 - varnishadm should be consistent in argv ordering.
• 1494 - Don't panic on VCL-initiated retry after a backend 500 error.
• 1139 - Also reset keep (for IMS) time when purging.
• 1478 - Avoid panic when delivering an object that expires during delivery.
• 1504 - ACLs can be unreferenced with vcc_err_unref=off set.
• 1501 - Handle that a director couldn't pick a backend.
• 1495 - Reduce WRK_SumStat contention.
• 1510 - Complain on symbol reuse in VCL.
• 1514 - Document storage.NAME.free_space and .used_space [docs]
• 1518 - Suppress body on 304 response when using ESI.
• 1519 - Round-robin director does not support weight. [docs]

Bugs fixed

• 1469 - Fix build error on PPC
• 1468 - Set ttl=0 on failed objects
• 1462 - Handle duplicate ReqURL in varnishncsa.
• 1467 - Fix missing clearing of oc->busyobj on HSH_Fail.

Bugs fixed

• 1460 - tools now use the new timestamp format.
• 1450 - varnishstat -l segmentation fault.
• 1320 - Work around Content-Length: 0 and Content-Encoding: gzip gracefully.
• 1458 - Panic on busy object.
• 1417 - Handle return(abandon) in vcl_backend_response.
• 1455 - vcl_pipe now sets Connection: close by default on backend requests.
• 1454 - X-Forwarded-For is now done in C, before vcl_recv is run.
• 1436 - Better explanation when missing an import in VCL.
• 1440 - Serve ESI-includes from a different backend.
• 1441 - Incorrect grouping when logging ESI subrequests.
• 1434 - std.duration can now do ms/milliseconds.
• 1419 - Don't put objcores on the ban list until they go non-BUSY.
• 1405 - Ban lurker does not always evict all objects.

New since from 4.0.0 TP1

• New VCL_BLOB type to pass binary data between VMODs.
• New format for VMOD description files. (.vcc)

Bugs fixed

• 1404 - Don't send Content-Length on 304 Not Modified responses.
• 1401 - Varnish would crash when retrying a backend fetch too many times.
• 1399 - Memory get freed while in use by another thread/object
• 1398 - Fix NULL deref related to a backend we don't know any more.
• 1397 - Crash on backend fetch while LRUing.
• 1395 - End up in vcl_error also if fetch fails vcl_backend_response.
• 1391 - Client abort and retry during a streaming fetch would make Varnish assert.
• 1390 - Fix assert if the ban lurker is overtaken by new duplicate bans.
• 1385 - ban lurker doesn't remove (G)one bans
• 1383 - varnishncsa logs requests for localhost regardless of host header.
• 1382 - varnishncsa prints nulls as part of request string.
• 1381 - Ensure vmod_director is installed
• 1323 - Add a missing boundary check for Range requests
• 1268 - shortlived parameter now uses TTL+grace+keep instead of just TTL.
• Fix build error on OpenBSD (TCP_KEEP)
• n_object wasn't being decremented correctly on object expire.
• Example default.vcl in distribution is now 4.0-ready.

Open issues

• 1405 - Ban lurker does not always evict all objects.

varnishd

• Always check the local address of a socket. This avoids a crash if server.ip is accessed after a client has closed the connection. Bug #1376

varnishd

• Stop printing error messages on ESI parse errors
• Fix a problem where Varnish would segfault if the first part of a synthetic page was NULL. Bug #1287
• If streaming was used, you could in some cases end up with duplicate content headers being sent to clients. Bug #1272
• If we receive a completely garbled request, don't pass through vcl_error, since we could then end up in vcl_recv through a restart and things would go downhill from there. Bug #1367
• Prettify backtraces on panic slightly.

varnishlog

• Correct an error where -m, -c and -b would interact badly, leading to lack of matches. Also, emit BackendXID to signify the start of a transaction. Bug #1325

varnishadm

• Handle input from stdin properly. Bug #1314

varnishd

• Set the waiter pipe as non-blocking and record overflows. Bug #1285
• Fix up a bug in the ACL compile code that could lead to false negatives. CVE-2013-4090. Bug #1312
• Return an error if the client sends multiple Host headers.

varnishd

• Fix error handling when uncompressing fetched objects for ESI processing. Bug #1184
• Be clearer about which timeout was reached in logs.
• Correctly decrement n_waitinglist counter. Bug #1261
• Turn off Nagle/set TCP_NODELAY.
• Avoid panic on malformed Vary headers. Bug #1275
• Increase the maximum length of backend names. Bug #1224
• Add support for banning on http.status. Bug #1076
• Make hit-for-pass correctly prefer the transient storage.

varnishlog

• If -m, but neither -b or -c is given, assume both. This filters out a lot of noise when -m is used to filter. Bug #1071

varnishadm

• Improve tab completion and require libedit/readline to build.

varnishtop

• Reopen log file if Varnish is restarted.

varnishncsa

• Handle file descriptors above 64k (by ignoring them). Prevents a crash in some cases with corrupted shared memory logs.
• Add %D and %T support for more timing information.

Other

• Documentation updates.
• Fixes for OSX
• Disable PCRE JIT-er, since it's broken in some PCRE versions, at least on i386.
• Make libvarnish prefer exact hits when looking for VSL tags.

varnishd

• Fix a race on the n_sess counter. This race made varnish do excessive session workspace allocations. Bug #897.
• Fix some crashes in the gzip code when it runs out of memory. Bug #1037. Bug #1043. Bug #1044.
• Fix a bug where the regular expression parser could end up in an infinite loop. Bug #1047.
• Fix a memory leak in the regex code.
• DNS director now uses port 80 by default if not specified.
• Introduce idle_send_timeout and increase default value for send_timeout to 600s. This allows a long send timeout for slow clients while still being able to disconnect idle clients.
• Fix an issue where <esi:remove> did not remove HTML comments. Bug #1092.
• Fix a crash when passing with streaming on.
• Fix a crash in the idle session timeout code.
• Fix an issue where the poll waiter did not timeout clients if all clients were idle. Bug #1023.
• Log regex errors instead of crashing.
• Introduce pcre_match_limit, and pcre_match_limit_recursion parameters.
• Add CLI commands to manually control health state of a backend.
• Fix an issue where the s_bodybytes counter is not updated correctly on gunzipped delivery.
• Fix a crash when we couldn't allocate memory for a fetched object. Bug #1100.
• Fix an issue where objects could end up in the transient store with a long TTL, when memory could not be allocated for them in the requested store. Bug #1140.
• Activate req.hash_ignore_busy when req.hash_always_miss is activated. Bug #1073.
• Reject invalid tcp port numbers for listen address. Bug #1035.
• Enable JIT for better performing regular expressions. Bug #1080.
• Return VCL errors in exit code when using -C. Bug #1069.
• Stricter validation of acl syntax, to avoid a crash with 5-octet IPv4 addresses. Bug #1126.
• Fix a crash when first argument to regsub was null. Bug #1125.
• Fix a case where varnish delivered corrupt gzip content when using ESI. Bug #1109.
• Fix a case where varnish didn't remove the old Date header and served it alongside the varnish-generated Date header. Bug #1104.
• Make saint mode work, for the case where we have no object with that hash. Bug #1091.
• Don't save the object body on hit-for-pass objects.
• n_ban_gone counter added to count the number of "gone" bans.
• Ban lurker rewritten to properly sleep when no bans are present, and otherwise to process the list at the configured speed.
• Fix a case where varnish delivered wrong content for an uncompressed page with compressed ESI child. Bug #1029.
• Fix an issue where varnish runs out of thread workspace when processing many ESI includes on an object. Bug #1038.
• Fix a crash when streaming was enabled for an empty body.
• Better error reporting for some fetch errors.
• Small performance optimizations.

varnishncsa

• Support for tn in varnishncsa format strings.
• Add new format: %{VCL_Log:foo}x which output key:value from std.log() in VCL.
• Add user-defined date formatting, using %{format}t.

varnishtest

• resp.body is now available for inspection.
• Make it possible to test for the absence of an HTTP header. Bug #1062.
• Log the full panic message instead of shortening it to 512 characters.

varnishstat

• Add json output (-j).

Other

• Documentation updates.
• Bump minimum number of threads to 50 in RPM packages.
• RPM packaging updates.
• Fix some compilation warnings on Solaris.
• Fix some build issues on Open/Net/DragonFly-BSD.
• Fix build on FreeBSD 10-current.
• Fix libedit detection on *BSD OSes. Bug #1003.

varnishd

• Make the size of the synthetic object workspace equal to http_resp_size and add workaround to avoid a crash when setting too long response strings for synthetic objects.
• Ensure the ban lurker always sleeps the advertised 1 second when it does not have anything to do.
• Remove error from vcl_deliver. Previously this would assert while it will now give a syntax error.

varnishncsa

• Add default values for some fields when logging incomplete records and document the default values.

Other

• Documentation updates
• Some Solaris portability updates.

varnishd

• Only log the first 20 bytes of extra headers to prevent overflows.
• Fix crasher bug which sometimes happened if responses are queued and the backend sends us Vary. Bug #994.
• Log correct size of compressed when uncompressing them for clients that do not support compression. Bug #996.
• Only send Range responses if we are going to send a body. Bug #1007.
• When varnishd creates a storage file, also unlink it to avoid leaking disk space over time. Bug #1008.
• The default size of the -s file parameter has been changed to 100MB instead of 50% of the available disk space.
• The limit on the number of objects we remove from the cache to make room for a new one was mistakenly lowered to 10 in 3.0.1. This has been raised back to 50. Bug #1012.
• http_req_size and http_resp_size have been increased to 8192 bytes. This better matches what other HTTPds have. Bug #1016.

VCL

• Allow relational comparisons of floating point types.
• Make it possible for VMODs to fail loading and so cause the VCL loading to fail.

varnishncsa

• Fixed crash when client was sending illegal HTTP headers.
• %{Varnish:handling} in format strings was broken, this has been fixed.

Other

• Documentation updates
• Some Solaris portability updates.

varnishd

• Fix crash in streaming code.
• Add fallback director, as a variant of the round-robin director.
• The parameter http_req_size has been reduced on 32 bit machines.

VCL

• Disallow error in the vcl_init and vcl_fini VCL functions.

varnishncsa

• Fixed crash when using -X.
• Fix error when the time to first byte was in the format string.

Other

• Documentation updates

varnishd

• Avoid sending an empty end-chunk when sending bodyless responses.
• http_resp_hdr_len and http_req_hdr_len were set to too low values leading to clients receiving HTTP 400 Bad Request errors. The limit has been increased and the error code is now HTTP 413 Request entity too large.
• Objects with grace or keep set were mistakenly considered as candidates for the transient storage. They now have their grace and keep limited to limit the memory usage of the transient stevedore.
• If a request was restarted from vcl_miss or vcl_pass it would crash. This has been fixed. Bug #965.
• Only the first few clients waiting for an object from the backend would be woken up when object arrived and this lead to some clients getting stuck for a long time. This has now been fixed. Bug #963.
• The hash and client directors would mistakenly retry fetching an object from the same backend unless health probes were enabled. This has been fixed and it will now retry a different backend.

VCL

• Request specific variables such as client.* and server.* are now correctly marked as not available in vcl_init and vcl_fini.
• The VCL compiler would fault if two IP comparisons were done on the same line. This now works correctly. Bug #948.

varnishncsa

• Add support for logging arbitrary request and response headers.
• Fix crashes if hitmiss and handling have not yet been set.
• Avoid printing partial log lines if there is an error in a format string.
• Report user specified format string errors better.

varnishlog

• varnishlog -r now works correctly again and no longer opens the shared log file of the running Varnish.

Other

• Various documentation updates.
• Minor compilation fixes for newer compilers.
• A bug in the ESI entity replacement parser has been fixed. Bug #961.
• The ABI of VMODs are now checked. This will require a rebuild of all VMODs against the new version of Varnish.

varnishd

• Avoid sending an empty end-chunk when sending bodyless responses.

VCL

• The synthetic keyword has now been properly marked as only available in vcl_deliver. Bug #936.

varnishadm

• Fix crash if the secret file was unreadable. Bug #935.
• Always exit if varnishadm can't connect to the backend for any reason.

varnishd

• thread_pool_min and thread_pool_max now each refer to the number of threads per pool, rather than being inconsistent as they were before.
• 307 Temporary redirect is now considered cacheable. Bug #908.
• The stats command has been removed from the CLI interface. With the new counters, it would mean implementing more and more of varnishstat in the master CLI process and the CLI is single-threaded so we do not want to do this work there in the first place. Use varnishstat instead.

VCL

• VCL now treats null arguments (unset headers for instance) as empty strings. Bug #913.
• VCL now has vcl_init and vcl_fini functions that are called when a given VCL has been loaded and unloaded.
• There is no longer any interpolation of the right hand side in bans where the ban is a single string. This was confusing and you now have to make sure bits are inside or outside string context as appropriate.
• Varnish is now stricter in enforcing no duplication of probes, backends and ACLs.

varnishncsa

• varnishncsa now ignores piped requests, since we have no way of knowing their return status.

VMODs

• The std module now has proper documentation, including a manual page

Upcoming changes

• The interpretation of bans will change slightly between 3.0 beta 1 and 3.0 release. Currently, doing ban("req.url == req.url") will cause the right hand req.url to be interpreted in the context of the request creating the ban. This will change so you will have to do ban("req.url == " + req.url) instead. This syntax already works and is recommended.

varnishd

• Add streaming on pass and miss. This is controlled by the beresp.do_stream boolean. This includes support for compression/uncompression.
• Add support for ESI and gzip.
• Handle objects larger than 2G.
• HTTP Range support is now enabled by default
• The ban lurker is enabled by default
• if there is a backend or director with the name default, use that as the default backend, otherwise use the first one listed.
• Add many more stats counters. Amongst those, add per storage backend stats and per-backend statistics.
• Syslog the platform we are running on
• The -l (shared memory log file) argument has been changed, please see the varnishd manual for the new syntax.
• The -S and -T arguments are now stored in the shmlog
• Fix off-by-one error when exactly filling up the workspace. Bug #693.
• Make it possible to name storage backends. The names have to be unique.
• Update usage output to match the code. Bug #683
• Add per-backend health information to shared memory log.
• Always recreate the shared memory log on startup.
• Add a vcl_dir parameter. This is used to resolve relative path names for vcl.load and include in .vcl files.
• Make it possible to specify -T :0. This causes varnishd to look for a free port automatically. The port is written in the shared memory log so varnishadm can find it.
• Classify locks into kinds and collect stats for each kind, recording the data in the shared memory log.
• Auto-detect necessary flags for pthread support and VCC_CC flags. This should make Varnish somewhat happier on Solaris. Bug #663
• The overflow_max parameter has been renamed to queue_max.
• If setting a parameter fails, report which parameter failed as this is not obvious during startup.
• Add a parameter named shortlived. Objects whose TTL is less than the parameter go into transient (malloc) storage.
• Reduce the default thread_add_delay to 2ms.
• The max_esi_includes parameter has been renamed to max_esi_depth.
• Hash string components are now logged by default.
• The default connect timeout parameter has been increased to 0.7 seconds.
• The err_ttl parameter has been removed and is replaced by a setting in default.vcl.
• The default send_timeout parameter has been reduced to 1 minute.
• The default ban_lurker sleep has been set to 10ms.
• When an object is banned, make sure to set its grace to 0 as well.
• Add panic.show and panic.clear CLI commands.
• The default http_resp_hdr_len and http_req_hdr_len has been increased to 2048 bytes.
• If vcl_fetch results in restart or error, close the backend connection rather than fetching the object.
• If allocating storage for an object, try reducing the chunk size before evicting objects to make room. Bug #880
• Add restart from vcl_deliver. Bug #411
• Fix an off-by-up-to-one-minus-epsilon bug where if an object from the backend did not have a last-modified header we would send out a 304 response which did include a Last-Modified header set to when we received the object. However, we would compare the timestamp to the fractional second we got the object, meaning any request with the exact timestamp would get a 200 response rather than the correct 304.
• Fix a race condition in the ban lurker where a serving thread and the lurker would both look at an object at the same time, leading to Varnish crashing.
• If a backend sends a Content-Length header and we are streaming and we are not uncompressing it, send the Content-Length header on, allowing browsers to diplay a progress bar.
• All storage must be at least 1M large. This is to prevent administrator errors when specifying the size of storage where the admin might have forgotten to specify units.

Tools

VMODs

• Add a std VMOD which includes a random function, log, syslog, fileread, collect,

VCL

• Change string concatenation to be done using + rather than implicitly.
• Stop using %xx escapes in VCL strings.
• Change req.hash += value to hash_data(value)
• Variables in VCL now have distinct read/write access
• bereq.connect_timeout is now available in vcl_pipe.
• Make it possible to declare probes outside of a director. Please see the documentation on how to do this.
• The VCL compiler has been reworked greatly, expanding its abilities with regards to what kinds of expressions it understands.
• Add beresp.backend.name, beresp.backend.ip and beresp.backend.port variables. They are only available from vcl_fetch and are read only. Bug #481
• The default VCL now calls pass for any objects where beresp.http.Vary == "*". Bug #787
• The log keyword has been moved to the std VMOD.
• It is now possible to choose which storage backend to be used
• Add variables storage.$name.free_space, storage.$name.used_space and storage.$name.happy
• The variable req.can_gzip tells us whether the client accepts gzipped objects or not.
• purge is now called ban, since that is what it really is and has always been.
• req.esi_level is now available. Bug #782
• esi handling is now controlled by the beresp.do_esi boolean rather than the esi function.
• beresp.do_gzip and beresp.do_gunzip now control whether an uncompressed object should be compressed and a compressed object should be uncompressed in the cache.
• make it possible to control compression level using the gzip_level parameter.
• obj.cacheable and beresp.cacheable have been removed. Cacheability is now solely through the beresp.ttl and beresp.grace variables.
• setting the obj.ttl or beresp.ttl to zero now also sets the corresponding grace to zero. If you want a non-zero grace, set grace after setting the TTL.
• return(pass) in vcl_fetch has been renamed to return(hit_for_pass) to make it clear that pass in vcl_fetch and vcl_recv are different beasts.
• Add actual purge support. Doing purge will remove an object and all its variants.

Libraries

• libvarnishapi has been overhauled and the API has been broken. Please see git commit logs and the support tools to understand what's been changed.
• Add functions to walk over all the available counters. This is needed because some of the counter names might only be available at runtime.
• Limit the amount of time varnishapi waits for a shared memory log to appear before returning an error.
• All libraries but libvarnishapi have been moved to a private directory as they are not for public consumption and have no ABI/API guarantees.

Other

• Python is now required to build
• Varnish Cache is now consistently named Varnish Cache.
• The compilation process now looks for kqueue on NetBSD
• Make it possible to use a system jemalloc rather than the bundled version.
• The documentation has been improved all over and should now be in much better shape than before

varnishd

• On pass from vcl_recv, we did not remove the backends Content-Length header before adding our own. This could cause confusion for browsers and has been fixed.
• Make pass with content-length work again. An issue with regards to 304, Content-Length and pass has been resolved.
• An issue relating to passed requests with If-Modified-Since headers has been fixed. Varnish did not recognize that the 304-response did not have a body.
• A potential lock-inversion with the ban lurker thread has been resolved.
• Several build-dependency issues relating to rst2man have been fixed. Varnish should now build from source without rst2man if you are using tar-balls.
• Ensure Varnish reads the expected last CRLF after chunked data from the backend. This allows re-use of the connection.
• Remove a GNU Make-ism during make dist to make BSD happier.
• Document the log, set, unset, return and restart statements in the VCL documentation.
• Fix an embarrassingly old bug where Varnish would run out of workspace when requests come in fast over a single connection, typically during synthetic benchmarks.
• Varnish will now allow If-Modified-Since requests to objects without a Last-Modified-header, and instead use the time the object was cached instead.
• Do not filter out Content-Range headers in pass.
• Require -d, -b, -f, -S or -T when starting varnishd. In human terms, this means that it is legal to start varnishd without a Vcl or backend, but only if you have a CLI channel of some kind.
• Don't suppress Cache-Control headers in pass responses.
• Merge multi-line Cache-Control and Vary header fields. Until now, no browsers have needed this, but Chromium seems to find it necessary to spread its Cache-Control across two lines, and we get to deal with it.
• Make new-purge not touch busy objects. This fixes a potential crash when calling VRT_purge.
• If there are everal grace-able objects, pick the least expired one.
• Fix an issue with varnishadm -T :6082 shorthand.
• Add bourn-shell like "here" documents on the CLI. Typical usage: vcl.inline vcl_new << 42 backend foo {...} sub vcl_recv {...} 42
• Add CLI version to the CLI-banner, starting with version 1.0 to mark here-documents.
• Fix a problem with the expiry thread slacking off during high load.

varnishtest

• Remove no longer existing -L option.

varnishd

• An embarrasing typo in the new binary heap layout caused inflated obj/objcore/objhdr counts and could cause odd problems when the LRU expunge mechanism was invoked. This has been fixed.
• We now have updated documentation in the reStructuredText format. Manual pages and reference documentation are both built from this.
• We now include a DNS director which uses DNS for choosing which backend to route requests to. Please see the documentation for more details.
• If you restarted a request, the HTTP header X-Forwarded-For would be updated multiple times. This has been fixed.
• If a VCL contained a % sign, and the vcl.show CLI command was used, varnishd would crash. This has been fixed.
• When doing a pass operation, we would remove the Content-Length, Age and Proxy-Auth headers. We are no longer doing this.
• now has a string representation, making it easier to construct Expires headers in VCL.
• In a high traffic environment, we would sometimes reuse a file descriptor before flushing the logs from a worker thread to the shared log buffer. This would cause confusion in some of the tools. This has been fixed by explicitly flushing the log when a backend connection is closed.
• If the communication between the management and the child process gets out of sync, we have no way to recover. Previously, varnishd would be confused, but we now just kill the child and restart it.
• If the backend closes the connection on us just as we sent a request to it, we retry the request. This should solve some interoperability problems with Apache and the mpm-itk multi processing module.
• varnishd now only provides help output the current CLI session is authenticated for.
• If the backend does not tell us which length indication it is using, we now assume the resource ends EOF at.
• The client director now has a variable client.identity which is used to choose which backend should receive a given request.
• The Solaris port waiter has been updated, and other portability fixes for Solaris.
• There was a corner case in the close-down processing of pipes, this has now been fixed.
• Previously, if we stopped polling a backend which was sick, it never got marked as healthy. This has now been changed.
• It is now possible to specify ports as part of the .host field in VCL.
• The synthetic counters were not locked properly, and so the sms_ counters could underflow. This has now been fixed.
• The value of obj.status as a string in vcl_error would not be correct in all cases. This has been fixed.
• Varnish would try to trim storage segments completely filled when using the malloc stevedore and the object was received chunked encoding. This has been fixed.
• If a buggy backend sends us a Vary header with two colons, we would previously abort. We now rather fix this up and ignore the extra colon.
• req.hash_always_miss and req.hash_ignore_busy has been added, to make preloading or periodically refreshing content work better.

varnishncsa

• varnishncsa would in some cases be confused by ESI requests and output invalid lines. This has now been fixed.

varnishlog

• varnishlog now allows -o and -u together.

varnishtop

• varnishtop would crash on 32 bit architectures. This has been fixed.

libvarnishapi

• Regex inclusion and exclusion had problems with matching particular parts of the string being matched. This has been fixed.

varnishd

• Improve scalability of critbit.
• The critbit hash algorithm has now been tightened to make sure the tree is in a consistent state at all points, and the time we wait for an object to cool off after it is eligible for garbage collection has been tweaked.
• Add log command to VCL. This emits a VCL_log entry into the shared memory log.
• Only emit Length and ReqEnd log entries if we actually have an XID. This should get rid of some empty log lines in varnishncsa.
• Destroy directors in a predictable fashion, namely reverse of creation order.
• Fix bug when ESI elements spanned storage elements causing a panic.
• In some cases, the VCL compiler would panic instead of giving sensible messages. This has now been fixed.
• Correct an off-by-one error when the requested range exceeds the size of an object.
• Handle requests for the end of an object correctly.
• Allow tabulator characters in the third field of the first line of HTTP requests
• On Solaris, if the remote end sends us an RST, all system calls related to that socket will return EINVAL. We now handle this better.

libvarnishapi

• The -X parameter didn't work correctly. This has been fixed.

varnishd

• When adding Range support for 2.1.1, we accidentally introduced a bug which would append garbage to objects larger than the chunk size, by default 128k. Browsers would do the right thing due to Content-Length, but some load balancers would get very confused.

varnishd

• The changelog in 2.1.0 included syntax errors, causing the generated changelog to be empty.
• The help text for default_grace was wrongly formatted and included a syntax error. This has now been fixed.
• varnishd now closes the file descriptor used to read the management secret file (from the -S parameter).
• The child would previously try to close every valid file descriptor, something which could cause problems if the file descriptor ulimit was set too high. We now keep track of all the file descriptors we open and only close up to that number.
• ESI was partially broken in 2.1.0 due to a bug in the rollback of session workspace. This has been fixed.
• Reject the authcommand rather than crash if there is no -S parameter given.
• Align pointers in allocated objects. This will in theory make Varnish a tiny bit faster at the expense of slightly more memory usage.
• Ensure the master process process id is updated in the shared memory log file after we go into the background.
• HEAD requests would be converted to GET requests too early, which affected pass and pipe. This has been fixed.
• Update the documentation to point out that the TTL is no longer taken into account to decide whether an object is cacheable or not.
• Add support for completely obliterating an object and all variants of it. Currently, this has to be done using inline C.
• Add experimental support for the Range header. This has to be enabled using the parameter http_range_support.
• The critbit hasher could get into a deadlock and had a race condition. Both those have now been fixed.

varnishsizes -----------~

• varnishsizes, which is like varnishhist, but for the length of objects, has been added..

varnishd

• Persistent storage is now experimentally supported using the persistent stevedore. It has the same command line arguments as the file stevedore.

• obj.* is now called beresp.* in vcl_fetch, and obj.* is now read-only.

• The regular expression engine is now PCRE instead of POSIX regular expressions.

• req.* is now available in vcl_deliver.

• Add saint mode where we can attempt to grace an object if we don't like the backend response for some reason.

  Related, add saintmode_threshold which is the threshold for the number of objects to be added to the trouble list before the backend is considered sick.

• Add a new hashing method called critbit. This autoscales and should work better on large object workloads than the classic hash. Critbit has been made the default hash algorithm.

• When closing connections, we experimented with sending RST to free up load balancers and free up threads more quickly. This caused some problems with NAT routers and so has been reverted for now.

• Add thread that checks objects against ban list in order to prevent ban list from growing forever. Note that this needs purges to be written so they don't depend on req.*. Enabled by setting ban_lurker_sleep to a nonzero value.

• The shared memory log file format was limited to maximum 64k simultaneous connections. This is now a 32 bit field which removes this limitation.

• Remove obj_workspace, this is now sized automatically.

• Rename acceptors to waiters

• vcl_prefetch has been removed. It was never fully implemented.

• Add support for authenticating CLI connections.

• Add hash director that chooses which backend to use depending on req.hash.

• Add client director that chooses which backend to use depending on the client's IP address. Note that this ignores the X-Forwarded-For header.

• varnishd now displays a banner by default when you connect to the CLI.

• Increase performance somewhat by moving statistics gathering into a per-worker structure that is regularly flushed to the global stats.

• Make sure we store the header and body of object together. This may in some cases improve performance and is needed for persistence.

• Remove client-side address accounting. It was never used for anything and presented a performance problem.

• Add a timestamp to bans, so you can know how old they are.

• Quite a few people got confused over the warning about not being able to lock the shared memory log into RAM, so stop warning about that.

• Change the default CLI timeout to 10 seconds.

• We previously forced all inserts into the cache to be GET requests. This has been changed to allow POST as well in order to be able to implement purge-on-POST semantics.

• The CLI command stats now only lists non-zero values.

• The CLI command stats now only lists non-zero values.

• Use daemon(3) from libcompat on Darwin.

• Remove vcl_discard as it causes too much complexity and never actually worked particularly well.

• Remove vcl_timeout as it causes too much complexity and never actually worked particularly well.

• Update the documentation so it refers to sess_workspace, not http_workspace.

• Document the -i switch to varnishd as well as the server.identity and server.hostname VCL variables.

• purge.hash is now deprecated and no longer shown in help listings.

• When processing ESI, replace the five mandatory XML entities when we encounter them.

• Add string representations of time and relative time.

• Add locking for n_vbe_conn to make it stop underflowing.

• When ESI-processing content, check for illegal XML character entities.

• Varnish can now connect its CLI to a remote instance when starting up, rather than just being connected to.

• It is no longer needed to specify the maximum number of HTTP headers to allow from backends. This is now a run-time parameter.

• The X-Forwarded-For header is now generated by vcl_recv rather than the C code.

• It is now possible to not send all CLI traffic to syslog.

• It is now possible to not send all CLI traffic to syslog.

• In the case of varnish crashing, it now outputs a identifying string with the OS, OS revision, architecture and storage parameters together with the backtrace.

• Use exponential backoff when we run out of file descriptors or sessions.

• Allow setting backend timeouts to zero.

• Count uptime in the shared memory log.

• Try to detect the case of two running varnishes with the same shmlog and storage by writing the master and child process ids to the shmlog and refusing to start if they are still running.

• Make sure to use EOF mode when serving ESI content to HTTP/1.0 clients.

• Make sure we close the connection if it either sends Connection: close or it is a HTTP/1.0 backend that does not send Connection: keep-alive.

• Increase the default session workspace to 64k on 64-bit systems.

• Make the epoll waiter use level triggering, not edge triggering as edge triggering caused problems on very busy servers.

• Handle unforeseen client disconnections better on Solaris.

• Make session lingering apply to new sessions, not just reused sessions.

varnishstat

• Make use of the new uptime field in the shared memory log rather than synthesizing it from the start time.

varnishlog

• Exit at the end of the file when started with -d.

varnishadm

• varnishadm can now have a timeout when trying to connect to the running varnishd.
• varnishadm now knows how to respond to the secret from a secured varnishd

varnishd

• 2.0.5 had an off-by-one error in the ESI handling causing includes to fail a large part of the time. This has now been fixed.
• Try harder to not confuse backends when sending them backend probes. We half-closed the connection, something some backends thought meant we had dropped the connection. Stop doing so, and add the capability for specifying the expected response code.
• In 2.0.5, session lingering was turned on. This caused statistics to not be counted often enough in some cases. This has now been fixed.
• Avoid triggering an assert if the other end closes the connection while we are lingering and waiting for another request from them.
• When generating backtraces, prefer the built-in backtrace function if such exists. This fixes a problem compiling 2.0.5 on Solaris.
• Make it possible to specify the per-thread stack size. This might be useful on 32 bit systems with their limited address space.
• Document the -C option to varnishd.

varnishd

• Handle object workspace overruns better.
• Allow turning off ESI processing per request by using set req.esi = off.
• Tell the kernel that we expect to use the mmap-ed file in a random fashion. On Linux, this turns off/down readahead and increases performance.
• Make it possible to change the maximum number of HTTP headers we allow by passing --with-max-header-fields=NUM rather than changing the code.
• Implement support for HTTP continuation lines.
• Change how connections are closed and only use SO_LINGER for orderly connection closure. This should hopefully make worker threads less prone to hangups on network problems.
• Handle multi-element purges correctly. Previously we ended up with parse errors when this was done from VCL.
• Handle illegal responses from the backend better by serving a 503 page rather than panic-ing.
• When we run into an assertion that is not true, Varnish would previously dump a little bit of information about itself. Extend that information with a backtrace. Note that this relies on the varnish binary being unstripped.
• Add a session_max parameter that limits the maximum number of sessions we keep open before we start dropping new connections summarily.
• Try to consume less memory when doing ESI processing by properly rolling back used workspace after processing an object. This should make it possible to turn sess_workspace quite a bit for users with ESI-heavy pages.
• Turn on session_linger by default. Tests have shown that session_linger helps a fair bit with performance.
• Rewrite the epoll acceptor for better performance. This should lead to both higher processing rates and maximum number of connections on Linux.
• Add If-None-Match support, this gives significant bandwidth savings for users with compliant browsers.
• RFC2616 specifies that ETag, Content-Location, Expires, Cache-Control and Vary should be emitted when delivering a response with the 304 response code.
• Various fixes which makes Varnish compile and work on AIX.
• Turn on TCP_DEFER_ACCEPT on Linux. This should make us less suspecible to denial of service attacks as well as give us slightly better performance.
• Add an .initial property to the backend probe specification. This is the number of good probes we pretend to have seen. The default is one less than .threshold, which means the first probe will decide if we consider the backend healthy.
• Make it possible to compare strings against other string-like objects, not just plain strings. This allows you to compare two headers, for instance.
• When support for restart in vcl_error was added, there was no check to prevent infinte recursion. This has now been fixed.
• Turn on purge_dups by default. This should make us consume less memory when there are many bans for the same pattern added.
• Add a new log tag called FetchError which tries to explain why we could not fetch an object from the backend.
• Change the default srcaddr_ttl to 0. It is not used by anything and has been removed in the development version. This will increase performance somewhat.

varnishtop

• varnishtop did not handle variable-length log fields correctly. This is now fixed.
• varnishtop previously did not print the name of the tag, which made it very hard to understand. We now print out the tag name.

varnishd

• Make Varnish more portable by pulling in fixes for Solaris and NetBSD.
• Correct description of -a in the manual page.
• Ensure we are compiling in C99 mode.
• If error was called with a null reason, we would crash on Solaris. Make sure this no longer happens.
• Varnish used to crash if you asked it to use a non-existent waiter. This has now been fixed.
• Add documentation to the default VCL explaining that using Connection: close in vcl_pipe is generally a good idea.
• Add minimal facility for dealing with TELNET option negotiation by returning WONT to DO and DONT requests.
• If the backend is unhealthy, use a graced object if one is available.
• Make server.hostname and server.identity available to VCL. The latter can be set with the -i parameter to varnishd.
• Make restart available from vcl_error.
• Previously, only the TTL of an object was considered in whether it would be marked as cacheable. This has been changed to take the grace into consideration as well.
• Previously, if an included ESI fragment had a zero size, we would send out a zero-sized chunk which signifies end-of-transmission. We now ignore zero-sized chunks.
• We accidentally slept for far too long when we reached the maximum number of open file descriptors. This has been corrected and accept_fd_holdoff now works correctly.
• Previously, when ESI processing, we did not look at the full length, but stopped at the first NULL byte. We no longer do that, enabling ESI processing of binary data.

varnishtest

• Make sure system "..." returns successfully to ensure test failures do not go unnoticed.
• Make it possible to send NULL bytes through the testing framework.

varnishd

• Handle If-Modified-Since and ESI sub-objects better, fixing a problem where we sometimes neglected to insert included objects.
• restart in vcl_hit is now supported.
• Setting the TTL of an object to 0 seconds would sometimes cause it to be delivered for up to one second - epsilon. This has been corrected and we should now never deliver those objects to other clients.
• The malloc storage backend now prints the maximum storage size, just like the file backend.
• Various small documentation bugs have been fixed.
• Varnish did not set a default interval for backend probes, causing it to poll the backend continuously. This has been corrected.
• Allow "true" and "false" when setting boolean parameters, in addition to on/off, enable/disable and yes/no.
• Default to always talking HTTP 1.1 with the backend.
• Varnish did not make sure the file it was loading was a regular file. This could cause Varnish to crash if it was asked to load a directory or other non-regular file. We now check that the file is a regular file before loading it.
• The binary heap used for expiry processing had scalability problems. Work around this by using stripes of a fixed size, which should make this scale better, particularly when starting up and having lots of objects.
• When we imported the jemalloc library into the Varnish tree, it did not compile without warnings. This has now been fixed.
• Varnish took a very long time to detect that the backend did not respond. To remedy this, we now have read timeouts in addition to the connect timeout. Both the first_byte_timeout and the between_bytes_timeout defaults to 60 seconds. The connect timeout is no longer in milliseconds, but rather in seconds.
• Previously, the VCL to C conversion as well as the invocation of the C compiler was done in the management process. This is now done in a separate sub-process. This prevents any bugs in the VCL compiler from affecting the management process.
• Chunked encoding headers were counted in the statistics for header bytes. They no longer are.
• ESI processed objects were not counted in the statistics for body bytes. They now are.
• It is now possible to adjust the maximum record length of log entries in the shmlog by tuning the shm_reclen parameter.
• The management parameters listed in the CLI were not sorted, which made it hard to find the parameter you were looking for. They are now sorted, which should make this easier.
• Add a new hashing type, "critbit", which uses a lock-less tree based lookup algorithm. This is experimental and should not be enabled in production environments without proper testing.
• The session workspace had a default size of 8k. It is now 16k, which should make VCLs where many headers are processed less prone to panics.
• We have seen that people seem to be confused as to which actions in the different VCL functions return and which ones don't. Add a new syntax return(action) to make this more explicit. The old syntax is still supported.
• Varnish would return an error if any of the management IPs listed in the -T parameter could not be listened to. We now only return an error if none of them can be listened to.
• In the case of the backend or client giving us too many parameters, we used to just ignore the overflowing headers. This is problematic if you end up ignoreing Content-Length, Transfer-Encoding and similar headers. We now give out a 400 error to the client if it sends us too many and 503 if we get too many from the backend.
• We used panic if we got a too large chunked header. This behaviour has been changed into just failing the transaction.
• Varnish now supports an extended purge method where it is possible to do purge req.http.host ~ "web1.com" && req.url ~ "\.png" and similar. See the documentation for details.
• Under heavy load, Varnish would sometimes crash when trying to update the per-request statistics. This has now been fixed.
• It is now possible to not save the hash string in the session and object workspace. This will save a lot of memory on sites with many small objects. Disabling the purge_hash parameter also disables the purge.hash facility.
• Varnish now supports !~ as a "no match" regular expression matcher.
• In some cases, you could get serialised access to "pass" objects. We now make it default to the default_ttl value; this can be overridden in vcl_fetch.
• Varnish did not check the syntax of regsub calls properly. More checking has been added.
• If the client closed the connection while Varnish was processing ESI elements, Varnish would crash while trying to write the object to the client. We now check if the client has closed the connection.
• The ESI parser had a bug where it would crash if an XML comment would span storage segments. This has been fixed.

VCL Manual page --------------~

• The documentation on how capturing parentheses work was wrong. This has been corrected.
• Grace has now been documented.

varnishreplay

• varnishreplay did not work correctly on Linux, due to a too small stack. This has now been fixed.

varnishd

• In high-load situations, when using ESI, varnishd would sometimes mishandle objects and crash. This has been worked around.

varnishreplay

• varnishreplay did not work correctly on Linux, due to a too small stack. This has now been fixed.

varnishd

• When receiving a garbled HTTP request, varnishd would sometimes crash. This has been fixed.
• There was an off-by-one error in the ACL compilation. Now fixed.

Red Hat spec file ----------------~

• A typo in the spec file made the .rpm file names wrong.

varnishd

• Only look for sendfile on platforms where we know how to use it, which is FreeBSD for now.
• Make it possible to adjust the shared memory log size and bump the size from 8MB to 80MB.
• Fix up the handling of request bodies to better match what RFC2616 mandates. This makes PUT, DELETE, OPTIONS and TRACE work in addition to POST.
• Change how backends are defined, to a constant structural defintion style. See https://www.varnish-cache.org/wiki/VclSyntaxChanges for the details.
• Add directors, which wrap backends. Currently, there's a random director and a round-robin director.
• Add "grace", which is for how long and object will be served, even after it has expired. To use this, both the object's and the request's grace parameter need to be set.
• Manual pages have been updated for new VCL syntax and varnishd options.
• Man pages and other docs have been updated.
• The shared memory log file is now locked in memory, so it should not be paged out to disk.
• We now handle Vary correctly, as well as Expect.
• ESI include support is implemented.
• Make it possible to limit how much memory the malloc uses.
• Solaris is now supported.
• There is now a regsuball function, which works like regsub except it replaces all occurrences of the regex, not just the first.
• Backend and director declarations can have a .connect_timeout parameter, which tells us how long to wait for a successful connection.
• It is now possible to select the acceptor to use by changing the acceptor parameter.
• Backends can have probes associated with them, which can be checked with req.backend.health in VCL as well as being handled by directors which do load-balancing.
• Support larger-than-2GB files also on 32 bit hosts. Please note that this does not mean we can support caches bigger than 2GB, it just means logfiles and similar can be bigger.
• In some cases, we would remove the wrong header when we were stripping Content-Transfer-Encoding headers from a request. This has been fixed.
• Backends can have a .max_connections associated with them.
• On Linux, we need to set the dumpable bit on the child if we want core dumps. Make sure it's set.
• Doing purge.hash() with an empty string would cause us to dump core. Fixed so we don't do that any more.
• We ran into a problem with glibc's malloc on Linux where it seemed like it failed to ever give memory back to the OS, causing the system to swap. We have now switched to jemalloc which appears not to have this problem.
• max_restarts was never checked, so we always ended up running out of workspace. Now, vcl_error is called when we reach max_restarts.

varnishtest

• varnishtest is a tool to do correctness tests of varnishd. The test suite is run by using make check.

varnishtop

• We now set the field widths dynamically based on the size of the terminal and the name of the longest field.

varnishstat

• varnishstat -1 now displays the uptime too.

varnishncsa

• varnishncsa now does fflush after each write. This makes tail -f work correctly, as well as avoiding broken lines in the log file.
• It is possible to get varnishncsa to output the X-Forwarded-For instead of the client IP by passing -f to it.

Build system -----------~

• Various sanity checks have been added to configure, it now complains about no ncurses or if SO_RCVTIMEO or SO_SNDTIMEO are non-functional. It also aborts if there's no working acceptor mechanism
• The C compiler invocation is decided by the configure script and can now be overridden by passing VCC_CC when running configure.

varnishd

• When switching to a new VCL configuration, a race condition exists which may cause Varnish to reference a backend which no longer exists (see ticket #144). This race condition has not been entirely eliminated, but it should occur less frequently.
• When dropping a TCP session before any requests were processed, an assertion would be triggered due to an uninitialized timestamp (see ticket #132). The timestamp is now correctly initialized.
• Varnish will now correctly generate a Date: header for every response instead of copying the one it got from the backend (see ticket #157).
• Comparisons in VCL which involve a non-existent string (usually a header which is not present in the request or object being processed) would cause a NULL pointer dereference; now the comparison will simply fail.
• A bug in the VCL compiler which would cause a double-free when processing include directives has been fixed.
• A resource leak in the worker thread management code has been fixed.
• When connecting to a backend, Varnish will usually get the address from a cache. When the cache is refreshed, existing connections may end up with a reference to an address structure which no longer exists, resulting in a crash. This race condition has been somewhat mitigated, but not entirely eliminated (see ticket #144.)
• Varnish will now pass the correct protocol version in pipe mode: the backend will get what the client sent, and vice versa.
• The core of the pipe mode code has been rewritten to increase robustness and eliminate spurious error messages when either end closes the connection in a manner Varnish did not anticipate.
• A memory leak in the backend code has been plugged.
• When using the kqueue acceptor, if a client shuts down the request side of the connection (as many clients do after sending their final request), it was possible for the acceptor code to receive the EOF event and recycle the session while the last request was still being serviced, resulting in a assertion failure and a crash when the worker thread later tried to delete the session. This should no longer happen (see ticket #162.)
• A mismatch between the recorded length of a cached object and the amount of data actually present in cache for that object can occasionally occur (see ticket #167.) This has been partially fixed, but may still occur for error pages generated by Varnish when a problem arises while retrieving an object from the backend.
• Some socket-related system calls may return unexpected error codes when operating on a TCP connection that has been shut down at the other end. These error codes would previously cause assertion failures, but are now recognized as harmless conditions.

varnishhist

• Pressing 0 though 9 while varnishhist is running will change the refresh interval to the corresponding power of two, in seconds.

varnishncsa

• The varnishncsa tool can now daemonize and write a PID file like varnishlog, using the same command-line options. It will also reopen its output upon receipt of a SIGHUP if invoked with -w.

varnishstat

• Pressing 0 though 9 while varnishstat is running will change the refresh interval to the corresponding power of two, in seconds.

Build system -----------~

• Varnish's <queue.h> has been modified to avoid conflicts with <sys/queue.h> on platforms where the latter is included indirectly through system headers.
• Several steps have been taken towards Solaris support, but this is not yet complete.
• When configure was run without an explicit prefix, Varnish's idea of the default state directory would be garbage and a state directory would have to be specified manually with -n. This has been corrected.

varnishd

• The code required to allow VCL to read obj.status, which had accidentally been left out, has now been added.
• Varnish will now always include a Connection: header in its reply to the client, to avoid possible misunderstandings.
• A bug that triggered an assertion failure when generating synthetic error documents has been corrected.
• A new VCL function, purge_url, provides the same functionality as the url.purge management command.
• Previously, Varnish assumed that the response body should be sent only if the request method was GET. This was a problem for custom request methods (such as PURGE), so the logic has been changed to always send the response body except in the specific case of a HEAD request.
• Changes to run-time parameters are now correctly propagated to the child process.
• Due to the way run-time parameters are initialized at startup, varnishd previously required the nobody user and the nogroup group to exist even if a different user and group were specified on the command line. This has been corrected.
• Under certain conditions, the VCL compiler would carry on after a syntax error instead of exiting after reporting the error. This has been corrected.
• The manner in which the hash string is assembled has been modified to reduce memory usage and memory-to-memory copying.
• Before calling vcl_miss, Varnish assembles a tentative request object for the backend request which will usually follow. This object would be leaked if vcl_miss returned anything else than fetch. This has been corrected.
• The code necessary to handle an error return from vcl_fetch and vcl_deliver had inadvertantly been left out. This has been corrected.
• Varnish no longer prints a spurious "child died" message (the result of reaping the compiler process) after compiling a new VCL configuration.
• Under some circumstances, due to an error in the workspace management code, Varnish would lose the "tail" of a request, i.e. the part of the request that has been received from the client but not yet processed. The most obvious symptom of this was that POST requests would work with some browsers but not others, depending on details of the browser's HTTP implementation. This has been corrected.
• On some platforms, due to incorrect assumptions in the CLI code, the management process would crash while processing commands received over the management port. This has been corrected.

Build system -----------~

• The top-level Makefile will now honor $DESTDIR when creating the state directory.
• The Debian and RedHat packages are now split into three (main / lib / devel) as is customary.
• A number of compile-time and run-time portability issues have been addressed.
• The autogen.sh script had workarounds for problems with the GNU autotools on FreeBSD; these are no longer needed and have been removed.
• The libcompat library has been renamed to libvarnishcompat and is now dynamic rather than static. This simplifies the build process and resolves an issue with the Mac OS X linker.

varnishd

• Readability of the C source code generated from VCL code has been improved.
• Equality (==) and inequality (!=) operators have been implemented for IP addresses (which previously could only be compared using ACLs).
• The address of the listening socket on which the client connection was received is now available to VCL as the server.ip variable.
• Each object's hash key is now computed based on a string which is available to VCL as req.hash. A VCL hook named vcl_hash has been added to allow VCL scripts to control hash generation (for instance, whether or not to include the value of the Host: header in the hash).
• The setup code for listening sockets has been modified to detect and handle situations where a host name resolves to multiple IP addresses. It will now attempt to bind to each IP address separately, and report a failure only if none of them worked.
• Network or protocol errors that occur while retrieving an object from a backend server now result in a synthetic error page being inserted into the cache with a 30-second TTL. This should help avoid driving an overburdened backend server into the ground by repeatedly requesting the same object.
• The child process will now drop root privileges immediately upon startup. The user and group to use are specified with the user and group run-time parameters, which default to nobody and nogroup, respectively. Other changes have been made in an effort to increase the isolation between parent and child, and reduce the impact of a compromise of the child process.
• Objects which are received from the backend with a Vary: header are now stored separately according to the values of the headers specified in Vary:. This allows Varnish to correctly cache e.g. compressed and uncompressed versions of the same object.
• Each Varnish instance now has a name, which by default is the host name of the machine it runs on, but can be any string that would be valid as a relative or absolute directory name. It is used to construct the name of a directory in which the server state as well as all temporary files are stored. This makes it possible to run multiple Varnish instances on the same machine without conflict.
• When invoked with the -C option, varnishd will now not just translate the VCL code to C, but also compile the C code and attempt to load the resulting shared object.
• Attempts by VCL code to reference a variable outside its scope or to assign a value to a read-only variable will now result in compile-time rather than run-time errors.
• The new command-line option -F will make varnishd run in the foreground, without enabling debugging.
• New VCL variables have been introduced to allow inspection and manipulation of the request sent to the backend (bereq.request, bereq.url, bereq.proto and bereq.http) and the response to the client (resp.proto, resp.status, resp.response and resp.http).
• Statistics from the storage code (including the amount of data and free space in the cache) are now available to varnishstat and other statistics-gathering tools.
• Objects are now kept on an LRU list which is kept loosely up-to-date (to within a few seconds). When cache runs out, the objects at the tail end of the LRU list are discarded one by one until there is enough space for the freshly requested object(s). A VCL hook, vcl_discard, is allowed to inspect each object and determine its fate by returning either keep or discard.
• A new VCL hook, vcl_deliver, provides a chance to adjust the response before it is sent to the client.
• A new management command, vcl.show, displays the VCL source code of any loaded configuration.
• A new VCL variable, now, provides VCL scripts with the current time in seconds since the epoch.
• A new VCL variable, obj.lastuse, reflects the time in seconds since the object in question was last used.
• VCL scripts can now add an HTTP header (or modify the value of an existing one) by assigning a value to the corresponding variable, and strip an HTTP header by using the remove keyword.
• VCL scripts can now modify the HTTP status code of cached objects (obj.status) and responses (resp.status)
• Numeric and other non-textual variables in VCL can now be assigned to textual variables; they will be converted as needed.
• VCL scripts can now apply regular expression substitutions to textual variables using the regsub function.
• A new management command, status, returns the state of the child.
• Varnish will now build and run on Mac OS X.

varnishadm

• This is a new utility which sends a single command to a Varnish server's management port and prints the result to stdout, greatly simplifying the use of the management port from scripts.

varnishhist

• The user interface has been greatly improved; the histogram will be automatically rescaled and redrawn when the window size changes, and it is updated regularly rather than at a rate dependent on the amount of log data gathered. In addition, the name of the Varnish instance being watched is displayed in the upper right corner.

varnishncsa

• In addition to client traffic, varnishncsa can now also process log data from backend traffic.
• A bug that would cause varnishncsa to segfault when it encountered an empty HTTP header in the log file has been fixed.

varnishreplay

• This new utility will attempt to recreate the HTTP traffic which resulted in the raw Varnish log data which it is fed.

varnishstat

• Don't print lifetime averages when it doesn't make any sense, for instance, there is no point in dividing the amount in bytes of free cache space by the lifetime in seconds of the varnishd process.
• The user interface has been greatly improved; varnishstat will no longer print more than fits in the terminal, and will respond correctly to window resize events. The output produced in one-shot mode has been modified to include symbolic names for each entry. In addition, the name of the Varnish instance being watched is displayed in the upper right corner in curses mode.

varnishtop

• The user interface has been greatly improved; varnishtop will now respond correctly to window resize events, and one-shot mode (-1) actually works. In addition, the name of the Varnish instance being watched is displayed in the upper right corner in curses mode.

varnishd

• The request workflow has been redesigned to simplify request processing and eliminate code duplication. All codepaths which need to speak HTTP now share a single implementation of the protocol. Some new VCL hooks have been added, though they aren't much use yet. The only real user-visible change should be that Varnish now handles persistent backend connections correctly (see ticket #56).

• Support for multiple listen addresses has been added.

• An "include" facility has been added to VCL, allowing VCL code to pull in code fragments from multiple files.

• Multiple definitions of the same VCL function are now concatenated into one in the order in which they appear in the source. This simplifies the mechanism for falling back to the built-in default for cases which aren't handled in custom code, and facilitates modularization.

• The code used to format management command arguments before passing them on to the child process would underestimate the amount of space needed to hold each argument once quotes and special characters were properly escaped, resulting in a buffer overflow. This has been corrected.

• The VCL compiler has been overhauled. Several memory leaks have been plugged, and error detection and reporting has been improved throughout. Parts of the compiler have been refactored to simplify future extension of the language.

• A bug in the VCL compiler which resulted in incorrect parsing of the decrement (-=) operator has been fixed.

• A new -C command-line option has been added which causes varnishd to compile the VCL code (either from a file specified with -f or the built-in default), print the resulting C code and exit.

• When processing a backend response using chunked encoding, if a chunk header crosses a read buffer boundary, read additional bytes from the backend connection until the chunk header is complete.

• A new ping_interval run-time parameter controls how often the management process checks that the worker process is alive.

• A bug which would cause the worker process to dereference a NULL pointer and crash if the backend did not respond has been fixed.

• In some cases, such as when they are used by AJAX applications to circumvent Internet Explorer's over-eager disk cache, it may be desirable to cache POST requests. However, the code path responsible for delivering objects from cache would only transmit the response body when replying to a GET request. This has been extended to also apply to POST.

  This should be revisited at a later date to allow VCL code to control whether the body is delivered.

• Varnish now respects Cache-control: s-maxage, and prefers it to Cache-control: max-age if both are present.

  This should be revisited at a later date to allow VCL code to control which headers are used and how they are interpreted.

• When loading a new VCL script, the management process will now load the compiled object to verify that it links correctly before instructing the worker process to load it.

• A new -P command-line options has been added which causes varnishd to create a PID file.

• The sendfile_threshold run-time parameter's default value has been set to infinity after a variety of sendfile()-related bugs were discovered on several platforms.

varnishlog

• When grouping log entries by request, varnishlog attempts to collapse the log entry for a call to a VCL function with the log entry for the corresponding return from VCL. When two VCL calls were made in succession, varnishlog would incorrectly omit the newline between the two calls (see ticket #95).
• New -D and -P command-line options have been added to daemonize and create a pidfile, respectively.
• The flag that is raised upon reception of a SIGHUP has been marked volatile so it will not be optimized away by the compiler.

varnishncsa

• The formatting callback has been largely rewritten for clarity, robustness and efficiency.

  If a request included a Host: header, construct and output an absolute URL. This makes varnishncsa output from servers which handle multiple virtual hosts far more useful.

• The flag that is raised upon reception of a SIGHUP has been marked volatile so it will not be optimized away by the compiler.

Documentation

• The documentation, especially the VCL documentation, has been greatly extended and improved.

Build system

• The name and location of the curses or ncurses library is now correctly detected by the configure script instead of being hardcoded into affected Makefiles. This allows Varnish to build correctly on a wider range of platforms.
• Compatibility shims for clock_gettime() are now correctly applied where needed, allowing Varnish to build on MacOS X.
• The autogen.sh script will now correctly detect and warn about automake versions which are known not to work correctly.