dovecot-2.2: lib-http: client: Added support for attempting a si...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/650629de6a73
changeset: 17774:650629de6a73
user:      Stephan Bosch <stephan at rename-it.nl>
date:      Wed Sep 10 13:39:37 2014 +0300
description:
lib-http: client: Added support for attempting a single IP several times.
Also limits the number of attempts when there are many IPs.

diffstat:

 src/lib-http/http-client-private.h |   2 ++
 src/lib-http/http-client-queue.c   |  23 ++++++++++++++++++++---
 src/lib-http/http-client.c         |   1 +
 src/lib-http/http-client.h         |  11 +++++++++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diffs (104 lines):

diff -r bf371c4fed6e -r 650629de6a73 src/lib-http/http-client-private.h
--- a/src/lib-http/http-client-private.h	Wed Sep 10 13:39:37 2014 +0300
+++ b/src/lib-http/http-client-private.h	Wed Sep 10 13:39:37 2014 +0300
@@ -182,6 +182,8 @@
 	   connected IP */
 	unsigned int ips_connect_start_idx;
 
+	unsigned int connect_attempts;
+
 	/* peers we are trying to connect to;
 	   this can be more than one when soft connect timeouts are enabled */
 	ARRAY_TYPE(http_client_peer) pending_peers;
diff -r bf371c4fed6e -r 650629de6a73 src/lib-http/http-client-queue.c
--- a/src/lib-http/http-client-queue.c	Wed Sep 10 13:39:37 2014 +0300
+++ b/src/lib-http/http-client-queue.c	Wed Sep 10 13:39:37 2014 +0300
@@ -158,13 +158,20 @@
 static bool
 http_client_queue_is_last_connect_ip(struct http_client_queue *queue)
 {
+	const struct http_client_settings *set =
+		&queue->client->set;
 	struct http_client_host *host = queue->host;
 
 	i_assert(queue->ips_connect_idx < host->ips_count);
 	i_assert(queue->ips_connect_start_idx < host->ips_count);
 
-	/* we'll always go through all the IPs. we don't necessarily start
-	   connecting from the first IP, so we'll need to treat the IPs as
+	/* if a maximum connect attempts > 1 is set, enforce it directly */
+	if (set->max_connect_attempts > 1) {
+		return queue->connect_attempts >= set->max_connect_attempts;
+	}
+		
+	/* otherwise, we'll always go through all the IPs. we don't necessarily
+	   start connecting from the first IP, so we'll need to treat the IPs as
 	   a ring buffer where we automatically wrap back to the first IP
 	   when necessary. */
 	return (queue->ips_connect_idx + 1) % host->ips_count ==
@@ -244,8 +251,14 @@
 				}
 			}
 		}
-		if (new_peer)
+		if (new_peer) {
+			http_client_queue_debug(queue, "Started new connection to %s%s",
+				http_client_peer_addr2str(addr), (addr->https_name == NULL ? "" :
+			t_strdup_printf(" (SSL=%s)", addr->https_name)));
+
 			array_append(&queue->pending_peers, &peer, 1);
+			queue->connect_attempts++;
+		}
 
 		/* start soft connect time-out (but only if we have another IP left) */
 		msecs = host->client->set.soft_connect_timeout_msecs;
@@ -265,6 +278,9 @@
 	queue->ips_connect_start_idx =
 		http_client_host_get_ip_idx(queue->host, &addr->ip);
 
+	/* reset attempt counter */
+	queue->connect_attempts = 0;
+
 	/* stop soft connect time-out */
 	if (queue->to_connect != NULL)
 		timeout_remove(&queue->to_connect);
@@ -343,6 +359,7 @@
 		   next request. */
 		queue->ips_connect_idx = queue->ips_connect_start_idx =
 			(queue->ips_connect_idx + 1) % host->ips_count;
+		queue->connect_attempts = 0;
 		http_client_queue_fail(queue,
 			HTTP_CLIENT_REQUEST_ERROR_CONNECT_FAILED, reason);
 		return FALSE;
diff -r bf371c4fed6e -r 650629de6a73 src/lib-http/http-client.c
--- a/src/lib-http/http-client.c	Wed Sep 10 13:39:37 2014 +0300
+++ b/src/lib-http/http-client.c	Wed Sep 10 13:39:37 2014 +0300
@@ -120,6 +120,7 @@
 	client->set.max_pipelined_requests =
 		(set->max_pipelined_requests > 0 ? set->max_pipelined_requests : 1);
 	client->set.max_attempts = set->max_attempts;
+	client->set.max_connect_attempts = set->max_connect_attempts;
 	client->set.no_auto_redirect = set->no_auto_redirect;
 	client->set.no_ssl_tunnel = set->no_ssl_tunnel;
 	client->set.max_redirects = set->max_redirects;
diff -r bf371c4fed6e -r 650629de6a73 src/lib-http/http-client.h
--- a/src/lib-http/http-client.h	Wed Sep 10 13:39:37 2014 +0300
+++ b/src/lib-http/http-client.h	Wed Sep 10 13:39:37 2014 +0300
@@ -81,6 +81,17 @@
 	/* maximum number of attempts for a request */
 	unsigned int max_attempts;
 
+	/* maximum number of connection attempts to a host before all associated
+	   requests fail.
+
+     if > 1, the maximum will be enforced across all IPs for that host,
+	   meaning that IPs may be tried more than once eventually if the number
+	   of IPs is smaller than the specified maximum attempts. If the number of IPs
+	   is higher than the maximum attempts, not all IPs are tried. If <= 1, all
+	   IPs are tried at most once.
+	 */
+	unsigned int max_connect_attempts;
+
 	/* response header limits */
 	struct http_header_limits response_hdr_limits;