VARNISH(CLI)VARNISH(CLI)NAME
Varnish CLI - Varnish Command Line Interface
DESCRIPTION
Varnish as a command line interface (CLI) which can control and change
most of the operational parameters and the configuration of Varnish,
without interrupting the running service.
The CLI can be used for the following tasks:
configuration
You can upload, change and delete VCL files from the CLI.
parameters
You can inspect and change the various parameters Varnish has
available through the CLI. The individual parameters are docu‐
mented in the varnishd(1) man page.
bans Bans are filters that are applied to keep Varnish from serving
stale content. When you issue a ban Varnish will not serve any
banned object from cache, but rather re-fetch it from its back‐
end servers.
process management
You can stop and start the cache (child) process though the CLI.
You can also retrieve the lastst stack trace if the child
process has crashed.
If you invoke varnishd(1) with -T, -M or -d the CLI will be
available. In debug mode (-d) the CLI will be in the foreground,
with -T you can connect to it with varnishadm or telnet and with
-M varnishd will connect back to a listening service pushing the
CLI to that service. Please see varnishd(1) for details.
Syntax
Commands are usually terminated with a newline. Long command can be
entered using sh style here documents. The format of here-documents is:
<< word
here document
word
word can be any continuous string choosen to make sure it doesn't
appear naturally in the following here document.
When using the here document style of input there are no restrictions
on lenght. When using newline-terminated commands maximum lenght is
limited by the varnishd parameter cli_buffer.
When commands are newline terminated they get tokenized before parsing
so if you have significant spaces enclose your strings in double
quotes. Within the quotes you can escape characters with \. The n, r
and t get translated to newlines, carrage returns and tabs. Double
quotes themselves can be escaped with a backslash.
To enter characters in octals use the \nnn syntax. Hexadecimals can be
entered with the \xnn syntax.
Commands
help [command]
Show command/protocol help
ping [timestamp]
Keep connection alive
auth response
Authenticate.
quit Close connection
banner Print welcome banner.
status Check status of Varnish cache process.
start Start the Varnish cache process.
stop Stop the Varnish cache process
vcl.load <configname> <filename>
Compile and load the VCL file under the name provided.
vcl.inline <configname> <quoted_VCLstring>
Compile and load the VCL data under the name provided.
vcl.use <configname>
Switch to the named configuration immediately.
vcl.discard <configname>
Unload the named configuration (when possible).
vcl.list
List all loaded configuration.
vcl.show <configname>
Display the source code for the specified configuration.
param.show [-l] [<param>]
Show parameters and their values.
param.set <param> <value>
Set parameter value.
panic.show
Return the last panic, if any.
panic.clear
Clear the last panic, if any.
storage.list
List storage devices
backend.list
List all backends
backend.set_health matcher state
Set health status on a backend
ban <field> <operator> <arg> [&& <field> <oper> <arg>]...
All objects where the all the conditions match will be marked
obsolete.
ban.list
List the active bans.
Ban Expressions
A ban expression consists of one or more conditions. A condition con‐
sists of a field, an operator, and an argument. Conditions can be
ANDed together with "&&".
A field can be any of the variables from VCL, for instance req.url,
req.http.host or obj.http.set-cookie.
Operators are "==" for direct comparision, "~" for a regular expression
match, and ">" or "<" for size comparisons. Prepending an operator
with "!" negates the expression.
The argument could be a quoted string, a regexp, or an integer. Inte‐
gers can have "KB", "MB", "GB" or "TB" appended for size related
fields.
Scripting
If you are going to write a script that talks CLI to varnishd, the
include/cli.h contains the relevant magic numbers.
One particular magic number to know, is that the line with the status
code and length field always is exactly 13 characters long, including
the NL character.
For your reference the sourcefile lib/libvarnish/cli_common.h contains
the functions Varnish code uses to read and write CLI response.
How -S/PSK Authentication Works
If the -S secret-file is given as argument to varnishd, all network CLI
connections must authenticate, by proving they know the contents of
that file.
The file is read at the time the auth command is issued and the con‐
tents is not cached in varnishd, so it is possible to update the file
on the fly.
Use the unix file permissions to control access to the file.
An authenticated session looks like this:
critter phk> telnet localhost 1234
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
107 59
ixslvvxrgkjptxmcgnnsdxsvdmvfympg
Authentication required.
auth 455ce847f0073c7ab3b1465f74507b75d3dc064c1e7de3b71e00de9092fdc89a
200 193
-----------------------------
Varnish HTTP accelerator CLI.
-----------------------------
Type 'help' for command list.
Type 'quit' to close CLI session.
Type 'start' to launch worker process.
The CLI status of 107 indicates that authentication is necessary. The
first 32 characters of the reponse text is the challenge "ixsl...mpg".
The challenge is randomly generated for each CLI connection, and
changes each time a 107 is emitted.
The most recently emitted challenge must be used for calculating the
authenticator "455c...c89a".
The authenticator is calculated by applying the SHA256 function to the
following byte sequence:
· Challenge string
· Newline (0x0a) character.
· Contents of the secret file
· Challenge string
· Newline (0x0a) character.
and dumping the resulting digest in lower-case hex.
In the above example, the secret file contained foon and thus:
critter phk> cat > _
ixslvvxrgkjptxmcgnnsdxsvdmvfympg
foo
ixslvvxrgkjptxmcgnnsdxsvdmvfympg
^D
critter phk> hexdump -C _
00000000 69 78 73 6c 76 76 78 72 67 6b 6a 70 74 78 6d 63 |ixslvvxrgkjptxmc|
00000010 67 6e 6e 73 64 78 73 76 64 6d 76 66 79 6d 70 67 |gnnsdxsvdmvfympg|
00000020 0a 66 6f 6f 0a 69 78 73 6c 76 76 78 72 67 6b 6a |.foo.ixslvvxrgkj|
00000030 70 74 78 6d 63 67 6e 6e 73 64 78 73 76 64 6d 76 |ptxmcgnnsdxsvdmv|
00000040 66 79 6d 70 67 0a |fympg.|
00000046
critter phk> sha256 _
SHA256 (_) = 455ce847f0073c7ab3b1465f74507b75d3dc064c1e7de3b71e00de9092fdc89a
critter phk> openssl dgst -sha256 < _
455ce847f0073c7ab3b1465f74507b75d3dc064c1e7de3b71e00de9092fdc89a
The sourcefile lib/libvarnish/cli_auth.c contains a useful function
which calculates the response, given an open filedescriptor to the
secret file, and the challenge string.
EXAMPLES
Simple example: All requests where req.url exactly matches the string
/news are banned from the cache:
req.url == "/news"
Example: Ban all documents where the serving host is "example.com" or
"www.example.com", and where the Set-Cookie header received from the
backend contains "USERID=1663":
req.http.host ~ "^(?i)(www\.)example.com$" && obj.http.set-cookie ~ "USERID=1663"
SEE ALSO
· varnishd(1)
· vanrishadm(1)
· vcl(7)HISTORY
The Varnish manual page was written by Per Buer in 2011. Some of the
text was taken from the Varnish Cache wiki, the varnishd(7) man page or
the Varnish source code.
COPYRIGHT
This document is licensed under the same licence as Varnish itself. See
LICENCE for details.
· Copyright (c) 2011-2014 Varnish Software AS
VARNISH(CLI)
