Varnish Default Config

default.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;

import std;

# Default backend definition. Set this to point to your content server.
backend default {
    .host = "localhost";
    .port = "8080";
}

sub vcl_recv {
    # Happens before we check if we have this in cache already.
    #
    # Typically you clean up the request here, removing cookies you don't need,
    # rewriting the request, etc.
    # Normalize the query arguments
    set req.url = std.querysort(req.url);

    # Remove the proxy header (see https://httpoxy.org/#mitigate-varnish)
    unset req.http.proxy;
    unset req.http.forwarded;

    # Only deal with "normal" types
    if (req.method != "GET" &&
        req.method != "HEAD" &&
        req.method != "PUT" &&
        req.method != "POST" &&
        req.method != "TRACE" &&
        req.method != "OPTIONS" &&
        req.method != "PATCH" &&
        req.method != "DELETE") {
        # Non-RFC2616 or CONNECT which is weird.
        return (pipe);
    }
}


sub vcl_hit {
    if (obj.ttl >= 0s) {
        # Normal hit
        return (deliver);
    } elsif (std.healthy(req.backend_hint)) {
        # The backend is healthy
        # Fetch the object from the backend
        return (miss);
    } else {
    # No fresh object and the backend is not healthy
        if (obj.ttl + obj.grace > 0s) {
            # Deliver graced object
            # Automatically triggers a background fetch
            return (deliver);
        } else {
            # No valid object to deliver
            # No healthy backend to handle request
            # Return error
            return (synth(503, "API is down"));
        }
    }
}

sub vcl_backend_response {
    # Happens after we have read the response headers from the backend.
    #
    # Here you clean the response headers, removing silly Set-Cookie headers
    # and other mistakes your backend does.
    if (beresp.status == 500 || beresp.status == 502 || beresp.status == 503 || beresp.status == 504) {
        return (abandon);
    }

    set beresp.http.url = bereq.url;
    set beresp.grace = 1h;
}

sub vcl_deliver {
    # Happens when we have all the pieces we need, and are about to send the
    # response to the client.
    #
    # You can do accounting or modifying the final object here.
    if (obj.hits > 0) { # Add debug header to see if it's a HIT/MISS and the number of hits, disable when not needed
        set resp.http.X-Cache = "HIT";
    } else {
        set resp.http.X-Cache = "MISS";
    }

    # Please note that obj.hits behaviour changed in 4.0, now it counts per objecthead, not per object
    # and obj.hits may not be reset in some cases where bans are in use. See bug 1492 for details.
    # So take hits with a grain of salt
    set resp.http.X-Cache-Hits = obj.hits;

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

    # Remove some headers: Apache version & OS
    unset resp.http.Server;
    unset resp.http.X-Drupal-Cache;
    unset resp.http.X-Varnish;
    unset resp.http.Via;
    unset resp.http.Link;
    unset resp.http.X-Generator;
    unset resp.http.X-Debug-Token;
    unset resp.http.X-Debug-Token-Link;

    set resp.http.X-Powered-By = "MIA<[email protected]>";
}