Hear from Slack, the ACLU, TED, & more at our customer summit in San Francisco Register
LOG IN SIGN UP
Documentation

Mixing and matching Fastly VCL with custom VCL

  Last updated March 29, 2017

Fastly Varnish syntax is specifically compatible with Varnish 2.1.5. We run a custom version with added functionality and our VCL parser has its own pre-processor. To mix and match Fastly VCL with your custom VCL successfully, remember the following:

Inserting custom VCL in Fastly's VCL boilerplate

Custom VCL placement example

sub vcl_miss {
  # my custom code
  if (req.http.User-Agent ~ "Googlebot") {
    set req.backend = F_special_google_backend;
  }
#FASTLY miss
  return(fetch);
}

Fastly's VCL boilerplate

sub vcl_recv {
#FASTLY recv

  if (req.request != "HEAD" && req.request != "GET" && req.request != "FASTLYPURGE") {
    return(pass);
  }

  return(lookup);
}

sub vcl_fetch {
#FASTLY fetch

  if ((beresp.status == 500 || beresp.status == 503) && req.restarts < 1 && (req.request == "GET" || req.request == "HEAD")) {
    restart;
  }

  if (req.restarts > 0) {
    set beresp.http.Fastly-Restarts = req.restarts;
  }

  if (beresp.http.Set-Cookie) {
    set req.http.Fastly-Cachetype = "SETCOOKIE";
    return(pass);
  }

  if (beresp.http.Cache-Control ~ "private") {
    set req.http.Fastly-Cachetype = "PRIVATE";
    return(pass);
  }

  if (beresp.status == 500 || beresp.status == 503) {
    set req.http.Fastly-Cachetype = "ERROR";
    set beresp.ttl = 1s;
    set beresp.grace = 5s;
    return(deliver);
  }

  if (beresp.http.Expires || beresp.http.Surrogate-Control ~ "max-age" || beresp.http.Cache-Control ~ "(s-maxage|max-age)") {
    # keep the ttl here
  } else {
    # apply the default ttl
    set beresp.ttl = 3600s;
  }

  return(deliver);
}

sub vcl_hit {
#FASTLY hit

  if (!obj.cacheable) {
    return(pass);
  }
  return(deliver);
}

sub vcl_miss {
#FASTLY miss
  return(fetch);
}

sub vcl_deliver {
#FASTLY deliver
  return(deliver);
}

sub vcl_error {
#FASTLY error
}

sub vcl_pass {
#FASTLY pass
}

sub vcl_log {
#FASTLY log
}

Back to Top