Author

Martin Blix Grydeland

Date

2011-05-26

Version

1.0

Manual section

3

import example;

Example Varnish vmod demonstrating how to write an out-of-tree Varnish vmod.

Implements the traditional Hello World as a vmod.

Prototype

hello(STRING S)

Return value

STRING

Description

Returns "Hello, " prepended to S

Example

set resp.http.hello = example.hello("World");

This is an example skeleton for developing out-of-tree Varnish vmods. It implements the "Hello, World!" as a vmod callback. Not particularly useful in good hello world tradition, but demonstrates how to get the glue around a vmod working.

The source tree is based on autotools to configure the building, and does also have the necessary bits in place to do functional unit tests using the varnishtest tool.

Usage:

./configure VARNISHSRC=DIR [VMODDIR=DIR]

VARNISHSRC is the directory of the Varnish source tree for which to compile your vmod. Both the VARNISHSRC and VARNISHSRC/include will be added to the include search paths for your module.

Optionally you can also set the vmod install directory by adding VMODDIR=DIR (defaults to the pkg-config discovered directory from your Varnish installation).

Make targets:

• make - builds the vmod
• make install - installs your vmod in VMODDIR
• make check - runs the unit tests in src/tests/*.vtc

In your VCL you could then use this vmod along the following lines:

import example;

sub vcl_deliver {
        # This sets resp.http.hello to "Hello, World"
        set resp.http.hello = example.hello("World");
}

This manual page was released as part of the libvmod-example package, demonstrating how to create an out-of-tree Varnish vmod.

This document is licensed under the same license as the libvmod-example project. See LICENSE for details.

• Copyright (c) 2011 Varnish Software