Built-in VCL

Introduction#

The built-in VCL contains procedures that are included and run last by Varnish.

They can complement user defined VCL by providing logic that is appropriate for the majority of the sites. For example, skips cache for POST requests, and/or in presence of cookie or authorization headers.

If some of the built-in logic is not needed, a user can add return() call from a procedure where built-in VCL logic is not desirable.

Varnish 3.0

/*-
 *
 * The default VCL code.
 *
 * NB! You do NOT need to copy & paste all of these functions into your
 * own vcl code, if you do not provide a definition of one of these
 * functions, the compiler will automatically fall back to the default
 * code from this file.
 *
 */

sub vcl_recv {
    if (req.restarts == 0) {
        if (req.http.x-forwarded-for) {
            set req.http.X-Forwarded-For =
                req.http.X-Forwarded-For + ", " + client.ip;
        } else {
            set req.http.X-Forwarded-For = client.ip;
        }
    }
    if (req.request != "GET" &&
      req.request != "HEAD" &&
      req.request != "PUT" &&
      req.request != "POST" &&
      req.request != "TRACE" &&
      req.request != "OPTIONS" &&
      req.request != "DELETE") {
        /* Non-RFC2616 or CONNECT which is weird. */
        return (pipe);
    }
    if (req.request != "GET" && req.request != "HEAD") {
        /* We only deal with GET and HEAD by default */
        return (pass);
    }
    if (req.http.Authorization || req.http.Cookie) {
        /* Not cacheable by default */
        return (pass);
    }
    return (lookup);
}

sub vcl_pipe {
    # Note that only the first request to the backend will have
    # X-Forwarded-For set.  If you use X-Forwarded-For and want to
    # have it set for all requests, make sure to have:
    # set bereq.http.connection = "close";
    # here.  It is not set by default as it might break some broken web
    # applications, like IIS with NTLM authentication.
    return (pipe);
}

sub vcl_pass {
    return (pass);
}

sub vcl_hash {
    hash_data(req.url);
    if (req.http.host) {
        hash_data(req.http.host);
    } else {
        hash_data(server.ip);
    }
    return (hash);
}

sub vcl_hit {
    return (deliver);
}

sub vcl_miss {
    return (fetch);
}

sub vcl_fetch {
    if (beresp.ttl <= 0s ||
        beresp.http.Set-Cookie ||
        beresp.http.Vary == "*") {
                /*
                 * Mark as "Hit-For-Pass" for the next 2 minutes
                 */
                set beresp.ttl = 120 s;
                return (hit_for_pass);
    }
    return (deliver);
}

sub vcl_deliver {
    return (deliver);
}

sub vcl_error {
    set obj.http.Content-Type = "text/html; charset=utf-8";
    set obj.http.Retry-After = "5";
    synthetic {"
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
 "https://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
  <head>
    <title>"} + obj.status + " " + obj.response + {"</title>
  </head>
  <body>
    <h1>Error "} + obj.status + " " + obj.response + {"</h1>
    <p>"} + obj.response + {"</p>
    <h3>Guru Meditation:</h3>
    <p>XID: "} + req.xid + {"</p>
    <hr>
    <p>Varnish cache server</p>
  </body>
</html>
"};
    return (deliver);
}

sub vcl_init {
        return (ok);
}

sub vcl_fini {
        return (ok);
}

Varnish 4.0

/*
 * The built-in (previously called default) VCL code.
 *
 * NB! You do NOT need to copy & paste all of these functions into your
 * own vcl code, if you do not provide a definition of one of these
 * functions, the compiler will automatically fall back to the default
 * code from this file.
 *
 * This code will be prefixed with a backend declaration built from the
 * -b argument.
 */

vcl 4.0;

#######################################################################
# Client side

sub vcl_recv {
    if (req.method == "PRI") {
    /* We do not support SPDY or HTTP/2.0 */
    return (synth(405));
    }
    if (req.method != "GET" &&
      req.method != "HEAD" &&
      req.method != "PUT" &&
      req.method != "POST" &&
      req.method != "TRACE" &&
      req.method != "OPTIONS" &&
      req.method != "DELETE") {
        /* Non-RFC2616 or CONNECT which is weird. */
        return (pipe);
    }

    if (req.method != "GET" && req.method != "HEAD") {
        /* We only deal with GET and HEAD by default */
        return (pass);
    }
    if (req.http.Authorization || req.http.Cookie) {
        /* Not cacheable by default */
        return (pass);
    }
    return (hash);
}

sub vcl_pipe {
    # By default Connection: close is set on all piped requests, to stop
    # connection reuse from sending future requests directly to the
    # (potentially) wrong backend. If you do want this to happen, you can undo
    # it here.
    # unset bereq.http.connection;
    return (pipe);
}

sub vcl_pass {
    return (fetch);
}

sub vcl_hash {
    hash_data(req.url);
    if (req.http.host) {
        hash_data(req.http.host);
    } else {
        hash_data(server.ip);
    }
    return (lookup);
}

sub vcl_purge {
    return (synth(200, "Purged"));
}

sub vcl_hit {
    if (obj.ttl >= 0s) {
        // A pure unadultered hit, deliver it
        return (deliver);
    }
    if (obj.ttl + obj.grace > 0s) {
        // Object is in grace, deliver it
        // Automatically triggers a background fetch
        return (deliver);
    }
    // fetch & deliver once we get the result
    return (fetch);
}

sub vcl_miss {
    return (fetch);
}

sub vcl_deliver {
    return (deliver);
}

/*
 * We can come here "invisibly" with the following errors: 413, 417 & 503
 */
sub vcl_synth {
    set resp.http.Content-Type = "text/html; charset=utf-8";
    set resp.http.Retry-After = "5";
    synthetic( {"<!DOCTYPE html>
<html>
  <head>
    <title>"} + resp.status + " " + resp.reason + {"</title>
  </head>
  <body>
    <h1>Error "} + resp.status + " " + resp.reason + {"</h1>
    <p>"} + resp.reason + {"</p>
    <h3>Guru Meditation:</h3>
    <p>XID: "} + req.xid + {"</p>
    <hr>
    <p>Varnish cache server</p>
  </body>
</html>
"} );
    return (deliver);
}

#######################################################################
# Backend Fetch

sub vcl_backend_fetch {
    return (fetch);
}

sub vcl_backend_response {
    if (beresp.ttl <= 0s ||
      beresp.http.Set-Cookie ||
      beresp.http.Surrogate-control ~ "no-store" ||
      (!beresp.http.Surrogate-Control &&
        beresp.http.Cache-Control ~ "no-cache|no-store|private") ||
      beresp.http.Vary == "*") {
        /*
        * Mark as "Hit-For-Pass" for the next 2 minutes
        */
        set beresp.ttl = 120s;
        set beresp.uncacheable = true;
    }
    return (deliver);
}

sub vcl_backend_error {
    set beresp.http.Content-Type = "text/html; charset=utf-8";
    set beresp.http.Retry-After = "5";
    synthetic( {"<!DOCTYPE html>
<html>
  <head>
    <title>"} + beresp.status + " " + beresp.reason + {"</title>
  </head>
  <body>
    <h1>Error "} + beresp.status + " " + beresp.reason + {"</h1>
    <p>"} + beresp.reason + {"</p>
    <h3>Guru Meditation:</h3>
    <p>XID: "} + bereq.xid + {"</p>
    <hr>
    <p>Varnish cache server</p>
  </body>
</html>
"} );
    return (deliver);
}

#######################################################################
# Housekeeping

sub vcl_init {
    return (ok);
}

sub vcl_fini {
    return (ok);
}