Provided by: varnish_7.1.1-1.1ubuntu1_amd64 
NAME
varnishncsa - Display Varnish logs in Apache / NCSA combined log format
SYNOPSIS
varnishncsa [-a] [-b] [-c] [-C] [-d] [-D] [-E] [-F <format>] [-f <formatfile>] [-g
<request|vxid>] [-h] [-j] [-L <limit>] [-n <dir>] [-P <file>] [-Q <file>] [-q <query>] [-r
<filename>] [-R <limit[/duration]>] [-t <seconds|off>] [-V] [-w <filename>]
DESCRIPTION
The varnishncsa utility reads varnishd(1) shared memory logs and presents them in the
Apache / NCSA "combined" log format.
Each log line produced is based on a single Request type transaction gathered from the
shared memory log. The Request transaction is then scanned for the relevant parts in order
to output one log line. To filter the log lines produced, use the query language to select
the applicable transactions. Non-request transactions are ignored.
The following options are available:
-a When writing output to a file, append to it rather than overwrite it. This option
has no effect without the -w option.
-b Log backend requests. If -c is not specified, then only backend requests will
trigger log lines.
-c Log client requests. This is the default. If -b is specified, then -c is needed to
also log client requests
-C Do all regular expression and string matching caseless.
-d Process log records at the head of the log and exit.
-D Daemonize.
-E Show ESI requests, implies client mode.
-F <format>
Set the output log format string.
-f <formatfile>
Read output format from a file. Will read a single line from the specified file,
and use that line as the format.
-g <request|vxid>
The grouping of the log records. The default is to group by vxid.
-h Print program usage and exit
-j Make format-specifier replacements JSON-compatible. When escaping characters, use
JSON-style \uXXXX escape sequences instead of C-style \xXX sequences. Empty strings
will be replaced with "" instead of "-", and empty integers will be replaced with
null. Use -F or -f in combination with -j to write JSON logs.
-L <limit>
Sets the upper limit of incomplete transactions kept before the oldest transaction
is force completed. A warning record is synthesized when this happens. This setting
keeps an upper bound on the memory usage of running queries. Defaults to 1000
transactions.
-n <dir>
Specify the varnishd working directory (also known as instance name) to get logs
from. If -n is not specified, the host name is used.
-P <file>
Write the process' PID to the specified file.
-Q <file>
Specifies the file containing the VSL query to use. When multiple -Q or -q options
are specified, all queries are considered as if the 'or' operator was used to
combine them.
-q <query>
Specifies the VSL query to use. When multiple -q or -Q options are specified, all
queries are considered as if the 'or' operator was used to combine them.
-r <filename>
Read log in binary file format from this file. The file can be created with
varnishlog -w filename. If the filename is -, logs are read from the standard
input. and cannot work as a daemon.
-R <limit[/duration]>
Restrict the output to the specified limit. Transactions exceeding the limit will
be suppressed. The limit is specified as the maximum number of transactions (with
respect to the chosen grouping method) and an optional time period. If no duration
is specified, a default of s is used. The duration field can be formatted as in VCL
(e.g. -R 10/2m) or as a simple time period without the prefix (e.g. -R 5/m). When
in -g raw grouping mode, this setting can not be used alongside -i, -I, -x or -X,
and we advise using -q instead.
-t <seconds|off>
Timeout before returning error on initial VSM connection. If set the VSM connection
is retried every 0.5 seconds for this many seconds. If zero the connection is
attempted only once and will fail immediately if unsuccessful. If set to "off", the
connection will not fail, allowing the utility to start and wait indefinetely for
the Varnish instance to appear. Defaults to 5 seconds.
-V Print version information and exit.
-w <filename>
Redirect output to file. The file will be overwritten unless the -a option was
specified. If the application receives a SIGHUP in daemon mode the file will be
reopened allowing the old one to be rotated away. This option is required when
running in daemon mode. If the filename is -, varnishncsa writes to the standard
output and cannot work as a daemon.
--optstring
Print the optstring parameter to getopt(3) to help writing wrapper scripts.
MODES
The default mode of varnishncsa is "client mode". In this mode, the log will be similar
to what a web server would produce in the absence of varnish. Client mode can be
explicitly selected by using -c.
If the -b switch is specified, varnishncsa will operate in "backend mode". In this mode,
requests generated by varnish to the backends will be logged. Unless -c is also
specified, client requests received by varnish will be ignored.
When running varnishncsa in both backend and client mode, it is strongly advised to
include the format specifier %{Varnish:side}x to distinguish between backend and client
requests.
Client requests that results in a pipe (ie. return(pipe) in vcl), will not generate
logging in backend mode. This is because varnish is not generating requests, but blindly
passes on bytes in both directions. However, a varnishncsa instance running in normal
mode can see this case by using the formatter %{Varnish:handling}x, which will be 'pipe'.
In backend mode, some of the fields in the format string get different meanings. Most
notably, the byte counting formatters (%b, %I, %O) considers varnish to be the client.
It is possible to keep two varnishncsa instances running, one in backend mode, and one in
client mode, logging to different files.
FORMAT
Specify the log format to use. If no format is specified the default log format is used:
%h %l %u %t "%r" %s %b "%{Referer}i" "%{User-agent}i"
Escape sequences \n and \t are supported.
Supported formatters are:
%b In client mode, size of response in bytes, excluding HTTP headers. In backend
mode, the number of bytes received from the backend, excluding HTTP headers. In
CLF format, i.e. a '-' rather than a 0 when no bytes are sent.
%D In client mode, time taken to serve the request, in microseconds. In backend mode,
time from the request was sent to the entire body had been received. This is
equivalent to %{us}T.
%H The request protocol. Defaults to HTTP/1.0 if not known.
%h Remote host. Defaults to '-' if not known. In backend mode this is the IP of the
backend server.
%I In client mode, total bytes received from client. In backend mode, total bytes
sent to the backend.
%{X}i The contents of request header X. If the header appears multiple times in a single
transaction, the last occurrence is used.
%l Remote logname. Always '-'.
%m Request method. Defaults to '-' if not known.
%{X}o The contents of response header X. If the header appears multiple times in a single
transaction, the last occurrence is used.
%O In client mode, total bytes sent to client. In backend mode, total bytes received
from the backend.
%q The query string. Defaults to an empty string if not present.
%r The first line of the request. Synthesized from other fields, so it may not be the
request verbatim. See the NOTES section.
%s Status sent to the client. In backend mode, status received from the backend.
%t In client mode, time when the request was received, in HTTP date/time format. In
backend mode, time when the request was sent.
%{X}t In client mode, time when the request was received, in the format specified by X.
In backend mode, time when the request was sent. The time specification format is
the same as for strftime(3) with these extensions:
• %{sec}: number of seconds since the Epoch
• %{msec}: number of milliseconds since the Epoch
• %{usec}: number of milliseconds since the Epoch
• %{msec_frac}: millisecond fraction
• %{usec_frac}: microsecond fraction
The extensions can not be combined with each other or strftime(3) in the same
specification. Use multiple %{X}t specifications instead.
%T In client mode, time taken to serve the request, in seconds. In backend mode, time
from the request was sent to the entire body had been received. This is equivalent
to %{s}T.
%{X}T In client mode, time taken to serve the request, in the format specified by X. In
backend mode, time from the request was sent to the entire body had been received.
The time specification format can be one of the following: s (same as %T), ms or us
(same as %D).
%U The request URL without the query string. Defaults to '-' if not known.
%u Remote user from auth.
%{X}x Extended variables. Supported variables are:
Varnish:time_firstbyte
Time from when the request processing starts until the first byte is sent to
the client, in seconds. For backend mode: Time from the request was sent to
the backend to the entire header had been received.
Varnish:hitmiss
One of the 'hit' or 'miss' strings, depending on whether the request was a
cache hit or miss. Pipe, pass and synth are considered misses.
Varnish:handling
One of the 'hit', 'miss', 'pass', 'pipe' or 'synth' strings indicating how
the request was handled.
Varnish:side
Backend or client side. One of two values, 'b' or 'c', depending on where
the request was made. In pure backend or client mode, this field will be
constant.
Varnish:vxid
The VXID of the varnish transaction.
VCL_Log:key
The value set by std.log("key:value") in VCL.
VSL:tag:record-prefix[field]
The value of the VSL entry for the given tag-record prefix-field
combination. Tag is mandatory, the other components are optional.
The record prefix will limit the matches to those records that have this
prefix as the first part of the record content followed by a colon.
The field will, if present, treat the log record as a white space separated
list of fields, and only the nth part of the record will be matched against.
Fields start counting at 1 and run up to 255.
Defaults to '-' when the tag is not seen, the record prefix does not match
or the field is out of bounds. If a tag appears multiple times in a single
transaction, the first occurrence is used.
SIGNALS
• SIGHUP
Rotate the log file (see -w option) in daemon mode, abort the loop and die gracefully
when running in the foreground.
• SIGUSR1
Flush any outstanding transactions.
NOTES
The %r formatter is equivalent to "%m http://%{Host}i%U%q %H". This differs from apache's
%r behavior, equivalent to "%m %U%q %H". Furthermore, when using the %r formatter, if the
Host header appears multiple times in a single transaction, the first occurrence is used.
EXAMPLE
Log the second field of the Begin record, corresponding to the VXID of the parent
transaction:
varnishncsa -F "%{VSL:Begin[2]}x"
Log the entire Timestamp record associated with the processing length:
varnishncsa -F "%{VSL:Timestamp:Process}x"
Log in JSON, using the -j flag to ensure that the output is valid JSON for all inputs:
varnishncsa -j -F '{"size": %b, "time": "%t", "ua": "%{User-Agent}i"}'
SEE ALSO
varnishd(1) varnishlog(1) varnishstat(1) vsl(7)
HISTORY
The varnishncsa utility was developed by Poul-Henning Kamp in cooperation with Verdens
Gang AS and Varnish Software AS. This manual page was initially written by Dag-Erling
Smørgrav <des@des.no>, and later updated by Martin Blix Grydeland and Pål Hermunn
Johansen.
COPYRIGHT
This document is licensed under the same licence as Varnish itself. See LICENCE for
details.
• Copyright (c) 2006 Verdens Gang AS
• Copyright (c) 2006-2016 Varnish Software AS
VARNISHNCSA(1)