VCL how to’s

In order for Zipnish to grab its required headers there are a few changes that are required in your VCL. There are two main scenarios to be handled here:

1. Caching disabled:

vcl 4.0;

backend DemoMicroservice {
    .host = "127.0.0.1";
    .port = "9999";
}

# disable caching - see further down for another example with caching enabled
sub vcl_recv {
    if (req.url ~ "^/DemoService") {
       set req.backend_hint = DemoMicroservice;
       return (pass);
    }
}

2. Caching enabled:

vcl 4.0;

backend DemoMicroservice {
    .host = "127.0.0.1";
    .port = "9999";
}

# disable caching - see further down for another example with caching enabled
sub vcl_recv {
    if (req.url ~ "^/DemoService") {
        set req.backend_hint = DemoMicroservice;
    }
}

sub vcl_deliver {
    # add the response headers if this is a cache hit
    if (obj.hits > 0) {
        if (req.http.x-varnish-trace) {
            set resp.http.x-varnish-trace = req.http.x-varnish-trace;
        } else {
            set resp.http.x-varnish-trace = req.http.x-varnish;
        }
        set resp.http.x-varnish-parent = req.http.x-varnish;
    }
}