[PATCH 2/2] examples/varnish-4.vcl: comments and tweaks

[Eric Wong <e@80x24.org>]

Document and simplify things a bit.  The major functional change
is we no longer waste space caching objects from dumb HTTP
clones.
---
 examples/varnish-4.vcl | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/examples/varnish-4.vcl b/examples/varnish-4.vcl
index 999f954..2429603 100644
--- 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);
-- 
EW