varnish-wordpress-configuration.vcl

#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and https://www.varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
backend default {
    .host = "10.0.0.10";
    .port = "81";
    .connect_timeout = 600s;
    .first_byte_timeout = 600s;
    .between_bytes_timeout = 600s;
    .max_connections = 800;
}

# Only allow purging from specific IPs
acl purge {
    "localhost";
    "127.0.0.1";
    "10.0.0.10";
}

# This function is used when a request is send by a HTTP client (Browser) 
sub vcl_recv {
        # Normalize the header, remove the port (in case you're testing this on various TCP ports)
        set req.http.Host = regsub(req.http.Host, ":[0-9]+", "");

        # Allow purging from ACL
        if (req.method == "PURGE") {
                # If not allowed then a error 405 is returned
                if (!client.ip ~ purge) {
                        return(synth(405, "This IP is not allowed to send PURGE requests."));
                }
                # If allowed, do a cache_lookup -> vlc_hit() or vlc_miss()
                return (purge);
        }

        # Post requests will not be cached
        if (req.http.Authorization || req.method == "POST") {
                return (pass);
        }

        # --- WordPress specific configuration

        # Did not cache the RSS feed
        if (req.url ~ "/feed") {
                return (pass);
        }

        # Blitz hack
        if (req.url ~ "/mu-.*") {
                return (pass);
        }


        # Did not cache the admin and login pages
        if (req.url ~ "/wp-(login|admin)") {
                return (pass);
        }


        # Remove the "has_js" cookie
        set req.http.Cookie = regsuball(req.http.Cookie, "has_js=[^;]+(; )?", "");

        # Remove any Google Analytics based cookies
        set req.http.Cookie = regsuball(req.http.Cookie, "__utm.=[^;]+(; )?", "");

        # Remove the Quant Capital cookies (added by some plugin, all __qca)
        set req.http.Cookie = regsuball(req.http.Cookie, "__qc.=[^;]+(; )?", "");

        # Remove the wp-settings-1 cookie
        set req.http.Cookie = regsuball(req.http.Cookie, "wp-settings-1=[^;]+(; )?", "");

        # Remove the wp-settings-time-1 cookie
        set req.http.Cookie = regsuball(req.http.Cookie, "wp-settings-time-1=[^;]+(; )?", "");

        # Remove the wp test cookie
        set req.http.Cookie = regsuball(req.http.Cookie, "wordpress_test_cookie=[^;]+(; )?", "");

        # Are there cookies left with only spaces or that are empty?
        if (req.http.cookie ~ "^ *$") {
                    unset req.http.cookie;
        }

        # Cache the following files extensions 
        if (req.url ~ "\.(css|js|png|gif|jp(e)?g|swf|ico)") {
                unset req.http.cookie;
        }

        # Normalize Accept-Encoding header and compression
        # https://www.varnish-cache.org/docs/3.0/tutorial/vary.html
        if (req.http.Accept-Encoding) {
                # Do no compress compressed files...
                if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
                                unset req.http.Accept-Encoding;
                } elsif (req.http.Accept-Encoding ~ "gzip") {
                        set req.http.Accept-Encoding = "gzip";
                } elsif (req.http.Accept-Encoding ~ "deflate") {
                        set req.http.Accept-Encoding = "deflate";
                } else {
                        unset req.http.Accept-Encoding;
                }
        }

        # Check the cookies for wordpress-specific items
        if (req.http.Cookie ~ "wordpress_" || req.http.Cookie ~ "comment_") {
                return (pass);
        }
        if (!req.http.cookie) {
                unset req.http.cookie;
        }

        # --- End of WordPress specific configuration

        # Do not cache HTTP authentication and HTTP Cookie
        if (req.http.Authorization || req.http.Cookie) {
                # Not cacheable by default
                return (pass);
        }

        # Cache all others requests
        return (hash);
}

sub vcl_pipe {
        return (pipe);
}

sub vcl_pass {
        return (fetch);
}

# The data on which the hashing will take place
sub vcl_hash {
        hash_data(req.url);
        if (req.http.host) {
             hash_data(req.http.host);
        } else {
             hash_data(server.ip);
        }

        # If the client supports compression, keep that in a different cache
        if (req.http.Accept-Encoding) {
             hash_data(req.http.Accept-Encoding);
        }

        return (lookup);
}


# This function is used when a request is sent by our backend (Nginx server)
sub vcl_backend_response {
        # Remove some headers we never want to see
        unset beresp.http.Server;
        unset beresp.http.X-Powered-By;

        # For static content strip all backend cookies
        if (bereq.url ~ "\.(css|js|png|gif|jp(e?)g)|swf|ico") {
                unset beresp.http.cookie;
        }

        # Only allow cookies to be set if we're in admin area
        if (beresp.http.Set-Cookie && bereq.url !~ "^/wp-(login|admin)") {
                unset beresp.http.Set-Cookie;
        }

        # don't cache response to posted requests or those with basic auth
        if ( bereq.method == "POST" || bereq.http.Authorization ) {
                set beresp.uncacheable = true;
                set beresp.ttl = 120s;
                return (deliver);
        }

        # don't cache search results
        if ( bereq.url ~ "\?s=" ){
                set beresp.uncacheable = true;
                set beresp.ttl = 120s;
                return (deliver);
        }

        # only cache status ok
        if ( beresp.status != 200 ) {
                set beresp.uncacheable = true;
                set beresp.ttl = 120s;
                return (deliver);
        }

        # A TTL of 24h
        set beresp.ttl = 24h;
        # Define the default grace period to serve cached content
        set beresp.grace = 30s;

        return (deliver);
}

# The routine when we deliver the HTTP request to the user
# Last chance to modify headers that are sent to the client
sub vcl_deliver {
        if (obj.hits > 0) {
                set resp.http.X-Cache = "cached";
        } else {
                set resp.http.x-Cache = "uncached";
        }

        # Remove some headers: PHP version
        unset resp.http.X-Powered-By;

        # Remove some headers: Apache version & OS
        unset resp.http.Server;

        # Remove some heanders: Varnish
        unset resp.http.Via;
        unset resp.http.X-Varnish;

        return (deliver);
}

sub vcl_init {
        return (ok);
}

sub vcl_fini {
        return (ok);
}

I am trying to get varnish to work on a clean Wordpress install and used many different vcl config files. This one seems to work perfectly. Except from purging from within Wordpress with the purge cache proxy plugin. I am far from an expert and can't figure out why. Have you use this vcl with latest version of WP and Varnish and did you by any chance use a purge plugin?

Kind regards

Hello @Japhys,
I used this configuration for an event where around 50K real-time users were expected. I used WP Rocket's purge feature that time, and I feel that purging was not working properly. I'll have a look at this configuration and I'll update it if I get a chance.

Thanks so much for your reply! I will keep an eye out for an update

Looks like I got it working with this plugin https://nl.wordpress.org/plugins/purge-varnish/

Only changing the backend ports in your file and point the plugin to terminal port 127.0.0.1:6082

Perfect. Thank you!