ha.varnish

ha.varnish

vcl 4.0;
import directors;

backend primary {
  .host = "127.0.0.1";
  .port = "8080";
}

backend replica {
  .host = "x.x.x.x";
  .port = "8080";
}

sub vcl_init {
  new pkgread = directors.round_robin();
  pkgread.add_backend(primary);
  pkgread.add_backend(replica);
}

sub vcl_backend_response {
  unset beresp.http.Etag;
  if (bereq.url ~ "@" || beresp.status >= 300 || bereq.method != "GET") {
    # DON'T CACHE SCOPED MODULES.
    set beresp.ttl = 0s;
  } else if (bereq.url ~ "\.tgz$") {
    # CACHE TARBALLS FOR A LONG TIME.
    set beresp.ttl = 21600s;
  } else if (bereq.url ~ "^/[^/]+$") {
    # DON'T CACHE JSON FOR LONG.
    set beresp.ttl = 300s;
  } else {
    # DON'T CACHE SPECIAL ROUTES
    set beresp.ttl = 0s;
  }
}

sub vcl_hash {
  hash_data(req.url);
  return (lookup);
}

sub vcl_recv {
  set req.http.X-Authorization = req.http.Authorization;
  unset req.http.Authorization;
  unset req.http.If-Modified-Since;
  if (req.method == "GET") {
   set req.backend_hint = pkgread.backend();
  } else {
   set req.backend_hint = primary;   
  }
}

sub vcl_backend_response {
    if (beresp.status >= 300 && bereq.retries == 0 && bereq.method == "GET") {
        return(retry);
    }
}

sub vcl_backend_fetch {
  set bereq.http.Authorization = bereq.http.X-Authorization;
  if (bereq.retries > 0) {
      set bereq.backend = primary;
  }
}