Skip to content

V
varnish-cache
Commit 0a4d6183 authored by Nils Goroll's avatar Nils Goroll
Browse files
Options

more consistent and RST-ish inline-markup -- starting with vcl.rst 

in particular

* VCL language and other literals as ``literal``
* placeholders and emphasis as *emphasis*
* no `interpreted text` except where it actually *is* that

Ref http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#character-level-inline-markup
parent 32090ef3
Show whitespace changes
Inline Side-by-side
Showing with 124 additions and 105 deletions
doc/README.WRITING_RST.rst
View file @ 0a4d6183
THINGS TO CONSIDER WHEN WRITING VARNISH RST DOCUMENTATION
=========================================================
Inline Markup
-------------
Please try to be consistent with inline markup and fix places which do
not follow the style:
* VCL language and other literals as ``literal``
* placeholders and emphasis as *emphasis*
* no `interpreted text` except where it actually *is* that
.. _Reference: http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#character-level-inline-markup
References are tricky
---------------------
......
doc/sphinx/reference/vcl.rst
View file @ 0a4d6183
......@@ -27,9 +27,9 @@ This document focuses on the syntax of the VCL language. For a full
description of syntax and semantics, with ample examples, please see
the online documentation at https://www.varnish-cache.org/docs/ .
Starting with Varnish 4.0, each VCL file must start by declaring its version
with "vcl X.Y;" marker at the top of the file. See more about this
under Versioning below.
Starting with Varnish 4.0, each VCL file must start by declaring its
version with ``vcl`` *<major>.<minor>*\ ``;`` marker at the top of
the file. See more about this under Versioning below.
Operators
......@@ -37,30 +37,31 @@ Operators
The following operators are available in VCL:
=
``=``
Assignment operator.
==
``==``
Comparison.
~
``~``
Match. Can either be used with regular expressions or ACLs.
!
``!``
Negation.
&&
``&&``
Logical and.
||
``||``
Logical or.
Conditionals
------------
VCL has *if* and *else* statements. Nested logic can be implemented
with the *elseif* statement (*elsif*/*elif*/*else if* are equivalent).
VCL has ``if`` and ``else`` statements. Nested logic can be
implemented with the ``elseif`` statement (``elsif``\ /\ ``elif``\ /\
``else if`` are equivalent).
Note that there are no loops or iterators of any kind in VCL.
......@@ -68,7 +69,7 @@ Note that there are no loops or iterators of any kind in VCL.
Strings, booleans, time, duration, integers and real numbers
------------------------------------------------------------
These are the data types in Varnish. You can *set* or *unset* these.
These are the data types in Varnish. You can ``set`` or ``unset`` these.
Example::
......@@ -79,58 +80,59 @@ Example::
Strings
~~~~~~~
Basic strings are enclosed in double quotes (" ... "), and may not contain
newlines. Long strings are enclosed in {" ... "}. They may contain any
character including single double quotes ("), newline and other control
characters except for the NUL (0x00) character.
Basic strings are enclosed in double quotes ``"``\ *...*\ ``"``, and
may not contain newlines. Long strings are enclosed in
``{"``\ *...*\ ``"}``. They may contain any character including single
double quotes ``"``, newline and other control characters except for the
*NUL* (0x00) character.
Booleans
~~~~~~~~
Booleans can be either *true* or *false*. In addition, in a boolean
context some data types will evaluate to *true* or *false* depending on
Booleans can be either ``true`` or ``false``. In addition, in a boolean
context some data types will evaluate to ``true`` or ``false`` depending on
their value.
String types will evaluate to *false* if they are empty; backend types
will evalute to *false* if they don't have a backend assigned; integer
types will evaluate to *false* if their value is zero; duration types
will evaluate to *false* if their value is equal or less than zero.
String types will evaluate to ``false`` if they are empty; backend types
will evalute to ``false`` if they don't have a backend assigned; integer
types will evaluate to ``false`` if their value is zero; duration types
will evaluate to ``false`` if their value is equal or less than zero.
Time
~~~~
VCL has time. A duration can be added to a time to make another time.
In string context they return a formatted string in RFC1123 format,
e.g. Sun, 06 Nov 1994 08:49:37 GMT.
e.g. ``Sun, 06 Nov 1994 08:49:37 GMT``.
The keyword *now* returns a time representing the current time in seconds
The keyword ``now`` returns a time representing the current time in seconds
since the Epoch.
Durations
~~~~~~~~~
Durations are defined by a number followed by a unit. The number can
include a fractional part, e.g. 1.5s. The supported units are:
include a fractional part, e.g. ``1.5s``. The supported units are:
ms
``ms``
milliseconds
s
``s``
seconds
m
``m``
minutes
h
``h``
hours
d
``d``
days
w
``w``
weeks
y
``y``
years
Integers
......@@ -172,7 +174,7 @@ To include a VCL file in another file use the include keyword::
Import statement
----------------
The *import* statement is used to load Varnish Modules (VMODs.)
The ``import`` statement is used to load Varnish Modules (VMODs.)
Example::
......@@ -184,8 +186,9 @@ Example::
Comments
--------
Single lines of VCL can be commented out using // or #. Multi-line blocks can
be commented out with \/\* block \/\*.
Single lines of VCL can be commented out using ``//`` or
``#``. Multi-line blocks can be commented out with
``/*``\ *block*\ ``*/``.
Example::
......@@ -202,45 +205,45 @@ Backend definition
------------------
A backend declaration creates and initialises a named backend object. A
declaration start with the keyword *backend* followed by the name of the
declaration start with the keyword ``backend`` followed by the name of the
backend. The actual declaration is in curly brackets, in a key/value fashion.::
backend name {
.attribute = "value";
}
The only mandatory attribute is *host*. The attributes will inherit
The only mandatory attribute is ``.host``. The attributes will inherit
their defaults from the global parameters. The following attributes
are available:
host (mandatory)
``.host`` *(mandatory)*
The host to be used. IP address or a hostname that resolves to a
single IP address.
port
``.port``
The port on the backend that Varnish should connect to.
host_header
``.host_header``
A host header to add to probes and regular backend requests if they have no
such header.
connect_timeout
``.connect_timeout``
Timeout for connections.
first_byte_timeout
``.first_byte_timeout``
Timeout for first byte.
between_bytes_timeout
``.between_bytes_timeout``
Timeout between bytes.
probe
``.probe``
Attach a probe to the backend. See `Probes`_
proxy_header
``.proxy_header``
The PROXY protocol version Varnish should use when connecting to
this backend. Allowed values are ``1`` and ``2``.
max_connections
``.max_connections``
Maximum number of open connections towards this backend. If
Varnish reaches the maximum Varnish it will start failing
connections.
......@@ -260,41 +263,41 @@ the backend as down it they fail. A probe is defined as this::
.attribute = "value";
}
The probe named `default` is special and will be used for all backends
The probe named ``default`` is special and will be used for all backends
which do not explicitly reference a probe.
There are no mandatory options. These are the options you can set:
url
The URL to query. Defaults to "/".
``.url``
The URL to query. Defaults to ``/``.
request
Specify a full HTTP request using multiple strings. .request will
have \\r\\n automatically inserted after every string. If
specified, .request will take precedence over .url.
``.request``
Specify a full HTTP request using multiple strings. ``.request`` will
have ``\r\n`` automatically inserted after every string. If
specified, ``.request`` will take precedence over ``.url``.
expected_response
The expected HTTP response code. Defaults to 200.
``.expected_response``
The expected HTTP response code. Defaults to ``200``.
timeout
The timeout for the probe. Default is 2s.
``.timeout``
The timeout for the probe. Default is ``2s``.
interval
How often the probe is run. Default is 5s.
``.interval``
How often the probe is run. Default is ``5s``.
initial
How many of the polls in .window are considered good when Varnish
starts. Defaults to the value of threshold - 1. In this case, the
``.initial``
How many of the polls in ``.window`` are considered good when Varnish
starts. Defaults to the value of ``.threshold`` - 1. In this case, the
backend starts as sick and requires one single poll to be
considered healthy.
window
``.window``
How many of the latest polls we examine to determine backend health.
Defaults to 8.
Defaults to ``8``.
threshold
``.threshold``
How many of the polls in .window must have succeeded for us to
consider the backend healthy. Defaults to 3.
consider the backend healthy. Defaults to ``3``.
Access Control List (ACL)
......@@ -325,14 +328,14 @@ To match an IP address against an ACL, simply use the match operator::
VCL objects
-----------
A VCL object can be instantiated with the *new* keyword::
A VCL object can be instantiated with the ``new`` keyword::
sub vcl_init {
new b = directors.round_robin()
b.add_backend(node1);
}
This is only available in vcl_init.
This is only available in ``vcl_init``.
Subroutines
-----------
......@@ -346,10 +349,11 @@ A subroutine is used to group code for legibility or reusability::
}
Subroutines in VCL do not take arguments, nor do they return
values. The built in subroutines all have names beginning with vcl\_,
values. The built in subroutines all have names beginning with ``vcl_``,
which is reserved.
To call a subroutine, use the call keyword followed by the subroutine's name::
To call a subroutine, use the ``call`` keyword followed by the
subroutine's name::
sub vcl_recv {
call pipe_if_local;
......@@ -358,11 +362,11 @@ To call a subroutine, use the call keyword followed by the subroutine's name::
Return statements
~~~~~~~~~~~~~~~~~
The ongoing vcl\_* subroutine execution ends when a return(*action*) statement
is made.
The ongoing ``vcl_*`` subroutine execution ends when a
``return(``\ *<action>*\ ``)`` statement is made.
The *action* specifies how execution should proceed. The context defines
which actions are available.
The *<action>* specifies how execution should proceed. The context
defines which actions are available.
Multiple subroutines
~~~~~~~~~~~~~~~~~~~~
......@@ -397,59 +401,59 @@ ban(STRING)
Invalidates all objects in cache that match the given expression with the
ban mechanism.
The format of `STRING` is::
The format of *STRING* is::
<field> <operator> <arg> [&& <field> <oper> <arg> ...]
* `<field>`:
* *<field>*:
* ``req.url``: The request url
* ``req.http.*``: Any request header
* ``obj.status``: The cache object status
* ``obj.http.*``: Any cache object header
* `<operator>`:
* *<operator>*:
* ``==``: `<field>` and `<arg>` are equal strings (case sensitive)
* ``!=``: `<field>` and `<arg>` are unequal strings (case sensitive)
* ``~``: `<field>` matches the regular expression `<arg>`
* ``!~``:`<field>` does not match the regular expression `<arg>`
* ``==``: *<field>* and *<arg>* are equal strings (case sensitive)
* ``!=``: *<field>* and *<arg>* are unequal strings (case sensitive)
* ``~``: *<field>* matches the regular expression *<arg>*
* ``!~``:*<field>* does not match the regular expression *<arg>*
* `<arg>`: Either a literal string or a regular expression. Note
that `<arg>` does not use any of the string delimiters like ``"``
or ``{"..."}`` used elsewhere in varnish. To match against strings
containing whitespace, regular expressions containing ``\s`` can
be used.
* *<arg>*: Either a literal string or a regular expression. Note
that *<arg>* does not use any of the string delimiters like ``"``
or ``{"``\ *...*\ ``"}`` used elsewhere in varnish. To match
against strings containing whitespace, regular expressions
containing ``\s`` can be used.
Expressions can be chained using the `and` operator ``&&``. For `or`
Expressions can be chained using the *and* operator ``&&``. For *or*
semantics, use several bans.
hash_data(input)
~~~~~~~~~~~~~~~~
Adds an input to the hash input. In the built-in VCL hash_data()
is called on the host and URL of the *request*. Available in vcl_hash.
Adds an input to the hash input. In the built-in VCL ``hash_data()``
is called on the host and URL of the request. Available in ``vcl_hash``.
synthetic(STRING)
~~~~~~~~~~~~~~~~~
Prepare a synthetic response body containing the STRING. Available in
vcl_synth and vcl_backend_error.
Prepare a synthetic response body containing the *STRING*. Available in
``vcl_synth`` and ``vcl_backend_error``.
.. list above comes from struct action_table[] in vcc_action.c.
regsub(str, regex, sub)
~~~~~~~~~~~~~~~~~~~~~~~
Returns a copy of str with the first occurrence of the regular
expression regex replaced with sub. Within sub, \\0 (which can
also be spelled \\&) is replaced with the entire matched string,
and \\n is replaced with the contents of subgroup n in the
matched string.
Returns a copy of *str* with the first occurrence of the regular
expression *regex* replaced with *sub*. Within *sub*, ``\0`` (which
can also be spelled ``\&``) is replaced with the entire matched
string, and ``\``\ *n* is replaced with the contents of subgroup *n*
in the matched string.
regsuball(str, regex, sub)
~~~~~~~~~~~~~~~~~~~~~~~~~~
As regsub() but this replaces all occurrences.
As ``regsub()``, but this replaces all occurrences.
.. regsub* is in vcc_expr.c
......@@ -462,18 +466,19 @@ Versioning
Multiple versions of the VCL syntax can coexist within certain
constraints.
The VCL syntax version at the start of VCL file specified with ''-f''
The VCL syntax version at the start of VCL file specified with ``-f``
sets the hard limit that cannot be exceeded anywhere, and it selects
the appropriate version of the builtin VCL.
That means that you can never include "vcl 9.1;" from "vcl 8.7;", but
the opposite *may* be possible, to the extent the compiler supports it.
That means that you can never include ``vcl 9.1;`` from ``vcl 8.7;``,
but the opposite *may* be possible, to the extent the compiler
supports it.
Files pulled in via ``include`` do not need to have a "vcl X.Y;" but
it may be a good idea to do it anyway, to not have surprises in the
future. The syntax version set in an included file only applies to
that file and any files it includes - unless these set their own VCL
syntax version.
Files pulled in via ``include`` do not need to have a
``vcl`` *X.Y*\ ``;`` but it may be a good idea to do it anyway, to
not have surprises in the future. The syntax version set in an
included file only applies to that file and any files it includes -
unless these set their own VCL syntax version.
The version of Varnish this file belongs to supports syntax 4.0 only.
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment