A small varnish vmod that allows to set the X-Request-Start header for use with
New Relic RPM more conveniently.
The vmod just encapsulates a small code snippet
(found here)
and offers a simple function for use in vcl scripts. See example below.
Dependening on the system setup it might be necessary to install the following packages
For example in Ubuntu:
sudo apt-get install libpcre3-dev libtool
Download the varnish source.
Unpack it to a folder and follow the instructions in the INSTALL file.
This should build varnish from source and install it on the system.
Varnish needs autoconf and automake installed.
In order to compile a varnish module successfully, path variables to the varnish source
and the vmods folder are necessary.
Either provide them by specifying environment variables.
export VARNISHSRC=path/to/varnish_src
export VMODDIR=/usr/local/lib/varnish/vmods/ # path might differ
or by providing these variables when calling the configure script.
./configure VARNISHSRC=path/to/varnish_src VMODDIR=/usr/local/lib/varnish/vmods/
The following steps install the vmod.
cd vmod
sh autogen.sh
./configure
make
make install
Running the autogen script can result in an error message, stating the "required file ltmain.sh not found".
It is suggested to re-run the script a second time.
After the vmod is installed just import the newrelic vmod and can be referenced with the
newrelic.set_x_request_start function at different points.
import newrelic;
backend default {
.host = "127.0.0.1";
.port = "4567";
}
sub vcl_recv {
newrelic.set_x_request_start();
}
To check that everything is correctly set up you can start a small test web application from he test
folder. It needs Ruby with the sinatra gem insalled. Just start it and should display the time stamp
of the X-Request-Start header