For new developments, we recommend to consider using https://github.com/Dridi/vcdk
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");
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.
Building requires the Varnish header files and uses pkg-config to find the necessary paths.
Usage:
./autogen.sh
./configure
If you have installed Varnish to a non-standard directory, call autogen.sh
and configure
with PKG_CONFIG_PATH
pointing to the appropriate path. For instance, when varnishd configure was called with --prefix=$PREFIX
, use
export PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig
export ACLOCAL_PATH=${PREFIX}/share/aclocal
The module will inherit its prefix from Varnish, unless you specify a different --prefix
when running the configure
script for this module.
Make targets:
- make - builds the vmod.
- make install - installs your vmod.
- make check - runs the unit tests in
src/tests/*.vtc
. - make distcheck - run check and prepare a tarball of the vmod.
If you build a dist tarball, you don't need any of the autotools or pkg-config. You can build the module simply by running:
./configure
make
By default, the vmod configure
script installs the built vmod in the directory relevant to the prefix. The vmod installation directory can be overridden by passing the vmoddir
variable to make install
.
In your VCL you could then use this vmod along the following lines:
import example;
sub vcl_deliver {
# This sets resp.http.hello to "Hello, World"
set resp.http.hello = example.hello("World");
}
configure: error: Need varnish.m4 -- see README.rst
Check whether
PKG_CONFIG_PATH
andACLOCAL_PATH
were set correctly before callingautogen.sh
andconfigure
Incompatibilities with different Varnish Cache versions
Make sure you build this vmod against its correspondent Varnish Cache version. For instance, to build against Varnish Cache 4.1, this vmod must be built from branch 4.1.
The basic steps to start a new vmod from this example are:
name=myvmod
git clone libvmod-example libvmod-$name
cd libvmod-$name
./rename-vmod-script $name
and follow the instructions output by rename-vmod-script