We are creating a CICD pipeline for apps hosting on Kubernetes. One of the things we like to do is to have the build number or any other version information visible in the UI. To achieve this with static webpages hosted in nginx we are using the server side include module and an environment variable.

Setup

The static webpages are hosted in nginx. In the html file(s) we add a special tag for server side include to print a variable.

<p>
    Hello there you are running container version 
    <!--# echo var="version" default="unknown" -->
</p>   

To enable the server side include module we provide a template that nginx processes before starting. This template will override the default website configuration to enable the server side include module and expand an environment variable.

# short version of the template
server {
    listen       80;
    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
        ssi    on;
        set    $version "${CONTAINER_VERSION}";
    }
}

Both the html file(s) and the template are copied into the container during docker build. When the container starts nginx will proces the template, enable ssi and expand the environment variable CONTAINER_VERSION. When hosting a html file with a server side include it will be executed and we see the version as part of the webpage.

For a detailed description and working code see my GitHub https://github.com/erictummers/nginx_k8s_ssi_demo