examples/varnish-4.vcl: comments and tweaks

Document and simplify things a bit.  The major functional change
is we no longer waste space caching objects from dumb HTTP
clones.

diff --git a/examples/varnish-4.vcl b/examples/varnish-4.vcl
index 999f954215a8f0383e2da36426309efb8d748199..24296032741fe18df2d90122d5b314a25acf6f5d 100644 (file)
--- a/examples/varnish-4.vcl
+++ b/examples/varnish-4.vcl
@@ -10,24 +10,15 @@
 
 vcl 4.0;
 backend default {
+       # this is where public-inbox-http listens
        .host = "127.0.0.1";
        .port = "280";
 }
 
 sub vcl_recv {
-       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);
-       }
+       /* pipe POST and any other weird methods directly to backend */
        if (req.method != "GET" && req.method != "HEAD") {
-               /* We only deal with GET and HEAD by default */
-               return (pass);
+               return (pipe);
        }
        if (req.http.Authorization || req.http.Cookie) {
                /* Not cacheable by default */
@@ -36,6 +27,13 @@ sub vcl_recv {
        return (hash);
 }
 
+sub vcl_pipe {
+       # By default Connection: close is set on all piped requests by varnish,
+       # but public-inbox-httpd supports persistent connections well :)
+       unset bereq.http.connection;
+       return (pipe);
+}
+
 sub vcl_hash {
        hash_data(req.url);
        if (req.http.host) {
@@ -43,6 +41,7 @@ sub vcl_hash {
        } else {
                hash_data(server.ip);
        }
+       /* we generate fully-qualified URLs for Atom feeds and redirects */
        if (req.http.X-Forwarded-Proto) {
                hash_data(req.http.X-Forwarded-Proto);
        }
@@ -53,6 +52,8 @@ sub vcl_backend_response {
        set beresp.grace = 60s;
        set beresp.do_stream = true;
        if (beresp.ttl <= 0s ||
+               /* no point in caching stuff git already stores on disk */
+               beresp.http.Content-Type ~ "application/x-git" ||
                beresp.http.Set-Cookie ||
                beresp.http.Vary == "*") {
                /* Mark as "Hit-For-Pass" for the next 2 minutes */
@@ -60,6 +61,7 @@ sub vcl_backend_response {
                set beresp.uncacheable = true;
                return (deliver);
        } else {
+               /* short TTL for up-to-dateness, our PSGI is not that slow */
                set beresp.ttl = 10s;
        }
        return (deliver);