From: Willy Tarreau <w@1wt.eu>
Date: Wed, 5 Aug 2015 14:02:46 +0000 (+0200)
Subject: MEDIUM: backend: implement "http-reuse safe"
X-Git-Tag: v1.6-dev4~108
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=161d45ffc72b2f6574094c26c220367fd83fc851;p=thirdparty%2Fhaproxy.git

MEDIUM: backend: implement "http-reuse safe"

The "safe" mode consists in picking existing connections only when
processing a request that's not the first one from a connection. This
ensures that in case where the server finally times out and closes, the
client can decide to replay idempotent requests.
---

diff --git a/src/backend.c b/src/backend.c
index 93eecbf0c7..18f688d1eb 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1046,8 +1046,9 @@ int connect_server(struct stream *s)
 			 */
 		}
 
-		if ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_ALWS &&
-		    !LIST_ISEMPTY(&srv->idle_conns)) {
+		if (((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_ALWS ||
+		     ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_SAFE && s->txn && (s->txn->flags & TX_NOT_FIRST)))
+		    && !LIST_ISEMPTY(&srv->idle_conns)) {
 			/* We're going to have to pick the first connection
 			 * from this pool and use it for our purposes. We may
 			 * have to get rid of the current idle connection, so
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 9a2316fc0c..9f7a6b53b3 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -5035,6 +5035,13 @@ stats_error_parsing:
 			if (alertif_too_many_args_idx(0, 1, file, linenum, args, &err_code))
 				goto out;
 		}
+		else if (strcmp(args[1], "safe") == 0) {
+			/* enable a graceful server shutdown on an HTTP 404 response */
+			curproxy->options &= ~PR_O_REUSE_MASK;
+			curproxy->options |= PR_O_REUSE_SAFE;
+			if (alertif_too_many_args_idx(0, 1, file, linenum, args, &err_code))
+				goto out;
+		}
 		else if (strcmp(args[1], "always") == 0) {
 			/* enable a graceful server shutdown on an HTTP 404 response */
 			curproxy->options &= ~PR_O_REUSE_MASK;
@@ -5043,7 +5050,7 @@ stats_error_parsing:
 				goto out;
 		}
 		else {
-			Alert("parsing [%s:%d] : '%s' only supports 'never', 'always'.\n", file, linenum, args[0]);
+			Alert("parsing [%s:%d] : '%s' only supports 'never', 'safe', 'always'.\n", file, linenum, args[0]);
 			err_code |= ERR_ALERT | ERR_FATAL;
 			goto out;
 		}