Fix an off-by-one error in the random director, which made it unable to

use the single remaining healthy backend.

Add regression test.

Fixes: ticket #306



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@3174 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_dir_random.c

@@ -96,14 +96,14 @@ vdi_random_getfd(struct sess *sp)
 		r *= s1;
 
 		s2 = 0;
-		j = 0;
 		for (i = 0; i < vs->nhosts; i++)  {
 			if (!vs->hosts[i].backend->healthy)
 				continue;
 			s2 += vs->hosts[i].weight;
-			if (r > s2)
-				j = i + 1;
+			if (r < s2)
+				break;
 		}
+
 		if (s2 != s1) {
 			/*
 			 * Health bit changed in an unusable way while we
@@ -112,7 +112,7 @@ vdi_random_getfd(struct sess *sp)
 			 */
 			continue;
 		}
-		vbe = VBE_GetVbe(sp, vs->hosts[j].backend);
+		vbe = VBE_GetVbe(sp, vs->hosts[i].backend);
 		if (vbe != NULL)
 			return (vbe);
 		k++;

bin/varnishtest/tests/r00306.vtc

+# $Id: v00007.vtc 3060 2008-08-01 12:44:53Z phk $
+
+test "Regression test for ticket #306, random director ignoring good backend"
+
+server s1 {
+
+	rxreq
+	expect req.url == /foo
+	txresp -body "foo1"
+
+	rxreq
+	expect req.url == /bar
+	txresp -body "bar1"
+
+} -start
+
+server s2 -listen 127.0.0.1:9180 {
+	rxreq
+	txresp -status 404
+} -start
+
+varnish v1 -vcl {
+	backend s1 {
+		.host = "127.0.0.1"; .port = "9080";
+	}
+	backend s2 {
+		.host = "127.0.0.1"; .port = "9180";
+		.probe = {
+			.url = "/";
+		}
+	}
+	director foo random {
+		{ .backend = s2; .weight = 1; }
+		{ .backend = s1; .weight = 1; }
+	}
+
+	sub vcl_recv {
+		set req.backend = foo;
+	}
+} -start
+
+client c1 {
+	timeout 10
+
+	txreq -url "/foo"
+	rxresp
+	expect resp.status == 200
+
+	txreq -url "/bar"
+	rxresp
+	expect resp.status == 200
+
+} -run