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This document describes the format and content of all the Varnish shared memory logging tags. These tags are used by the varnishlog(1), varnishtop(1), etc. logging tools supplied with Varnish.
Logged when a connection is selected for handling a backend request.
The format is:
%d %s %s
| | |
| | +- Backend display name
| +---- VCL name
+------- Connection file descriptor
NOTE: This tag is currently not in use in the Varnish log. It is mentioned here to document legacy versions of the log, or reserved for possible use in future versions.
Logged when a backend connection is closed.
The format is:
%d %s %s [ %s ]
| | | |
| | | +- Optional reason
| | +------ "close" or "recycle"
| +--------- Backend display name
+------------ Connection file descriptor
Logged when a new backend connection is opened.
The format is:
%d %s %s %s %s %s %s
| | | | | | |
| | | | | | +- "connect" or "reuse"
| | | | | +---- Local port
| | | | +------- Local address
| | | +---------- Remote port
| | +------------- Remote address
| +---------------- Backend display name
+------------------- Connection file descriptor
Logged when a backend connection is put up for reuse by a later connection.
The format is:
%d %s
| |
| +- Backend display name
+---- Connection file descriptor
NOTE: This tag is currently not in use in the Varnish log. It is mentioned here to document legacy versions of the log, or reserved for possible use in future versions.
Start of backend processing. Logs the backend IP address and port number.
The format is:
%s %s
| |
| +- Backend Port number
+---- Backend IP4/6 address
NOTE: This tag is currently not in use in the Varnish log. It is mentioned here to document legacy versions of the log, or reserved for possible use in future versions.
The result of a backend health probe.
The format is:
%s %s %s %s %u %u %u %f %f %s
| | | | | | | | | |
| | | | | | | | | +- Probe HTTP response / error information
| | | | | | | | +---- Average response time
| | | | | | | +------- Response time
| | | | | | +---------- Probe window size
| | | | | +------------- Probe threshold level
| | | | +---------------- Number of good probes in window
| | | +------------------- Probe window bits
| | +---------------------- "healthy" or "sick"
| +------------------------- "Back", "Still" or "Went"
+---------------------------- Backend name
Probe window bits are:
'4': Good IPv4
'6': Good IPv6
'U': Good UNIX
'x': Error Xmit
'X': Good Xmit
'r': Error Recv
'R': Good Recv
'H': Happy
The first record of a VXID transaction.
The format is:
%s %d %s
| | |
| | +- Reason
| +---- Parent vxid
+------- Type ("sess", "req" or "bereq")
Contains byte counters from backend request processing.
The format is:
%d %d %d %d %d %d
| | | | | |
| | | | | +- Total bytes received
| | | | +---- Body bytes received
| | | +------- Header bytes received
| | +---------- Total bytes transmitted
| +------------- Body bytes transmitted
+---------------- Header bytes transmitted
HTTP header contents.
The format is:
%s: %s
| |
| +- Header value
+----- Header name
NOTE: HTTP header fields are free form records and not strictly made of 2 fields. Accessing a specific header with the prefix notation helps treating the header value as a single string.
HTTP header contents.
The format is:
%s: %s
| |
| +- Header value
+----- Header name
NOTE: HTTP header fields are free form records and not strictly made of 2 fields. Accessing a specific header with the prefix notation helps treating the header value as a single string.
Debug messages can normally be ignored, but are sometimes helpful during trouble-shooting. Most debug messages must be explicitly enabled with parameters.
Debug messages may be added, changed or removed without prior notice and shouldn't be considered stable.
NB: This log record is masked by default.
Logs events related to object expiry. The events are:
The format is:
EXP_Rearm p=%p E=%f e=%f f=0x%x
EXP_Inbox p=%p e=%f f=0x%x
EXP_Kill p=%p e=%f f=0x%x
EXP_When p=%p e=%f f=0x%x
EXP_Expired x=%u t=%f
LRU_Cand p=%p f=0x%x r=%d
LRU x=%u
LRU_Fail
Legend:
p=%p Objcore pointer
t=%f Remaining TTL (s)
e=%f Expiry time (unix epoch)
E=%f Old expiry time (unix epoch)
f=0x%x Objcore flags
r=%d Objcore refcount
x=%u Object VXID
Logs the error message of a failed fetch operation.
Error messages should be self-explanatory, yet the http connection (HTC) class of errors is reported with these symbols:
- junk (-5): Received unexpected data
- close (-4): Connection closed
- timeout (-3): Timed out
- overflow (-2): Buffer/workspace too small
- eof (-1): Unexpected end of input
- empty (0): Empty response
- more (1): More data required
- complete (2): Data complete (no error)
- idle (3): Connection was closed while idle
Notice that some HTC errors are never emitted.
Ready to fetch body from backend.
The format is:
%d %s %s
| | |
| | +---- 'stream' or '-'
| +------- Text description of body fetch mode
+---------- Body fetch mode
A Gzip record is emitted for each instance of gzip or gunzip work performed. Worst case, an ESI transaction stored in gzip'ed objects but delivered gunziped, will run into many of these.
The format is:
%c %c %c %d %d %d %d %d
| | | | | | | |
| | | | | | | +- Bit length of compressed data
| | | | | | +---- Bit location of 'last' bit
| | | | | +------- Bit location of first deflate block
| | | | +---------- Bytes output
| | | +------------- Bytes input
| | +---------------- 'E': ESI, '-': Plain object
| +------------------- 'F': Fetch, 'D': Deliver
+---------------------- 'G': Gzip, 'U': Gunzip, 'u': Gunzip-test
Examples:
U F E 182 159 80 80 1392
G F E 159 173 80 1304 1314
This value was added to the object lookup hash.
NB: This log record is masked by default.
Object looked up in cache.
The format is:
%u %f %f %f
| | | |
| | | +- Keep period
| | +---- Grace period
| +------- Remaining TTL
+---------- VXID of the object
Hit-for-miss object looked up in cache.
The format is:
%u %f
| |
| +- Remaining TTL
+---- VXID of the object
Hit-for-pass object looked up in cache.
The format is:
%u %f
| |
| +- Remaining TTL
+---- VXID of the object
Links this VXID to any child VXID it initiates.
The format is:
%s %d %s
| | |
| | +- Reason
| +---- Child vxid
+------- Child type ("req" or "bereq")
Informational log messages on events occured during request handling.
The format is:
%s: %s
| |
| +- Short description of the notice message
+----- Manual page containing the detailed description
See the NOTICE MESSAGES section below or the individual VMOD manual pages for detailed information of notice messages.
HTTP header contents.
The format is:
%s: %s
| |
| +- Header value
+----- Header name
NOTE: HTTP header fields are free form records and not strictly made of 2 fields. Accessing a specific header with the prefix notation helps treating the header value as a single string.
Contains byte counters for pipe sessions.
The format is:
%d %d %d %d
| | | |
| | | +------- Piped bytes to client
| | +---------- Piped bytes from client
| +------------- Backend request headers
+---------------- Client request headers
PROXY protocol information.
The format is:
%d %s %d %s %d
| | | | |
| | | | +- server port
| | | +---- server ip
| | +------- client port
| +---------- client ip
+------------- PROXY protocol version
All fields are "local" for PROXY local connections (command 0x0)
Contains byte counts for the request handling. The body bytes count includes transmission overhead (ie: chunked encoding). ESI sub-requests show the body bytes this ESI fragment including any subfragments contributed to the top level request. The format is:
%d %d %d %d %d %d
| | | | | |
| | | | | +- Total bytes transmitted
| | | | +---- Body bytes transmitted
| | | +------- Header bytes transmitted
| | +---------- Total bytes received
| +------------- Body bytes received
+---------------- Header bytes received
HTTP header contents.
The format is:
%s: %s
| |
| +- Header value
+----- Header name
NOTE: HTTP header fields are free form records and not strictly made of 2 fields. Accessing a specific header with the prefix notation helps treating the header value as a single string.
Start of request processing. Logs the client address, port number and listener endpoint name (from the -a command-line argument).
The format is:
%s %s %s
| | |
| | +-- Listener name (from -a)
| +----- Client Port number (0 for Unix domain sockets)
+-------- Client IP4/6 address (0.0.0.0 for UDS)
HTTP header contents.
The format is:
%s: %s
| |
| +- Header value
+----- Header name
NOTE: HTTP header fields are free form records and not strictly made of 2 fields. Accessing a specific header with the prefix notation helps treating the header value as a single string.
SessClose is the last record for any client connection.
The format is:
%s %f
| |
| +- How long the session was open
+---- Why the connection closed
Accepting a client connection has failed.
The format is:
%s %s %s %d %d %s
| | | | | |
| | | | | +- Detailed error message
| | | | +---- Error Number (errno) from accept(2)
| | | +------- File descriptor number
| | +---------- Local TCP port / 0 for UDS
| +------------- Local IPv4/6 address / 0.0.0.0 for UDS
+---------------- Socket name (from -a argument)
The first record for a client connection, with the socket-endpoints of the connection.
The format is:
%s %d %s %s %s %d
| | | | | |
| | | | | +- File descriptor number
| | | | +---- Local TCP port / 0 for UDS
| | | +------- Local IPv4/6 address / 0.0.0.0 for UDS
| | +---------- Socket name (from -a argument)
| +------------- Remote TCP port / 0 for UDS
+---------------- Remote IPv4/6 address / 0.0.0.0 for UDS
Type and name of the storage backend the object is stored in.
The format is:
%s %s
| |
| +- Name of storage backend
+---- Type ("malloc", "file", "persistent" etc.)
A TTL record is emitted whenever the ttl, grace or keep values for an object is set as well as whether the object is cacheable or not.
The format is:
%s %d %d %d %d [ %d %d %u %u ] %s
| | | | | | | | | |
| | | | | | | | | +- "cacheable" or "uncacheable"
| | | | | | | | +------ Max-Age from Cache-Control header
| | | | | | | +--------- Expires header
| | | | | | +------------ Date header
| | | | | +--------------- Age (incl Age: header value)
| | | | +-------------------- Reference time for TTL
| | | +----------------------- Keep
| | +-------------------------- Grace
| +----------------------------- TTL
+-------------------------------- "RFC", "VCL" or "HFP"
The four optional fields are only present in "RFC" headers.
Examples:
RFC 60 10 -1 1312966109 1312966109 1312966109 0 60 cacheable
VCL 120 10 0 1312966111 uncacheable
HFP 2 0 0 1312966113 uncacheable
Contains timing information for the Varnish worker threads.
Time stamps are issued by Varnish on certain events, and show the absolute time of the event, the time spent since the start of the work unit, and the time spent since the last timestamp was logged. See the TIMESTAMPS section below for information about the individual time stamps.
The format is:
%s: %f %f %f
| | | |
| | | +- Time since last timestamp
| | +---- Time since start of work unit
| +------- Absolute time of event
+----------- Event label
Logs VCL ACL evaluation results.
The format is:
%s [%s [%s [fixed: %s]]]
| | | |
| | | +- Fixed entry (see vcc_acl_pedantic parameter)
| | +------------ Matching entry (only for MATCH)
| +---------------- Name of the ACL for MATCH or NO_MATCH
+-------------------- MATCH, NO_MATCH or NO_FAM
MATCH denotes an ACL match NO_MATCH denotes that a checked ACL has not matched NO_FAM denotes a missing address family and should not occur.
Logs VCL execution trace data.
The format is:
%s %u %u.%u.%u
| | | | |
| | | | +- VCL program line position
| | | +---- VCL program line number
| | +------- VCL program source index
| +---------- VCL trace point index
+------------- VCL configname
NB: This log record is masked by default.
Records the name of the VCL being used.
The format is:
%s [ %s %s ]
| | |
| | +- Name of label used to find it
| +---- "via"
+--------- Name of VCL put in use
Contains name of VFP and statistics.
The format is:
%s %d %d
| | |
| | +- Total bytes produced
| +---- Number of calls made
+------- Name of filter
NB: This log record is masked by default.
Logs worker thread creation and termination events.
The format is:
%p %s
| |
| +- [start|end]
+---- Worker struct pointer
NB: This log record is masked by default.
Timestamps are inserted in the log on completing certain events during the worker thread's task handling. The timestamps has a label showing which event was completed. The reported fields show the absolute time of the event, the time spent since the start of the task and the time spent since the last timestamp was logged.
The timestamps logged automatically by Varnish are inserted after completing events that are expected to have delays (e.g. network IO or spending time on a waitinglist). Timestamps can also be inserted from VCL using the std.timestamp() function. If one is doing time consuming tasks in the VCL configuration, it's a good idea to log a timestamp after completing that task. This keeps the timing information in subsequent timestamps from including the time spent on the VCL event.
Notice messages contain informational messages about the handling of a request. These can be exceptional circumstances encountered that causes deviation from the normal handling. The messages are prefixed with vsl for core Varnish generated messages, and VMOD authors are encouraged to use vmod_<name> for their own notice messages. This matches the name of the manual page where detailed descriptions of notice messages are expected.
The core messages are described below.
The backend answered 304 Not Modified on a conditional fetch using an object that has not yet been fully fetched as the stale template object. This can only happen when the TTL of the object is less than the time it takes to fetch it. The fetch is halted until the stale object is fully fetched, upon which the new object is created as normal. While waiting, any grace time on the stale object will be in effect.
This document was initially written by Poul-Henning Kamp, and later updated by Martin Blix Grydeland.
This document is licensed under the same licence as Varnish itself. See LICENCE for details.
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