Reference

vmod_softpurge(3)

purge vmod

NAME

vmod_softpurge - purge vmod

SYNOPSIS

import softpurge [from "path"] ;

DESCRIPTION

Softpurge is cache invalidation in Varnish that reduces TTL but keeps the grace value of a resource.

This makes it possible to serve stale content to users if the backend is unavailable and fresh content can not be fetched.

CONTENTS

•

func_softpurge

softpurge

VOID softpurge()

Performs a soft purge. Valid in vcl_hit and vcl_miss.

Example:

sub vcl_hit {
    if (req.method == "PURGE") {
        softpurge.softpurge();
    }
}

USAGE

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

import softpurge;
sub vcl_recv {
    if (req.method == "PURGE") {
        return (hash);
    }
}
sub vcl_backend_response {
    set beresp.grace = 10m;
}
sub vcl_hit {
    if (req.method == "PURGE") {
        softpurge.softpurge();
        return (synth(200, "Successful softpurge"));
    }
}
sub vcl_miss {
    if (req.method == "PURGE") {
        softpurge.softpurge();
        return (synth(200, "Successful softpurge"));
    }
}