From: Stephan Bosch <stephan@dovecot.fi>
Date: Sat, 16 Apr 2016 01:54:00 +0000 (+0200)
Subject: lib-http: server: Implemented means to gracefully shut down the server.
X-Git-Tag: 2.3.0.rc1~3885
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e1a4ea6ad3e799ef8df7395e765c0ae9218e6c5d;p=thirdparty%2Fdovecot%2Fcore.git

lib-http: server: Implemented means to gracefully shut down the server.

While shutting down, it will not accept new requests and connections are closed once they become idle.
---

diff --git a/src/lib-http/http-server-connection.c b/src/lib-http/http-server-connection.c
index 94713e6805..6e166817e3 100644
--- a/src/lib-http/http-server-connection.c
+++ b/src/lib-http/http-server-connection.c
@@ -151,6 +151,16 @@ http_server_connection_timeout_reset(struct http_server_connection *conn)
 		timeout_reset(conn->to_idle);
 }
 
+bool http_server_connection_shut_down(struct http_server_connection *conn)
+{
+	if (conn->request_queue_head == NULL ||
+		conn->request_queue_head->state == HTTP_SERVER_REQUEST_STATE_NEW) {
+		http_server_connection_close(&conn, "Server shutting down");
+		return TRUE;
+	}
+	return FALSE;
+}
+
 static void http_server_connection_ready(struct http_server_connection *conn)
 {
 	struct stat st;
@@ -403,17 +413,24 @@ static bool
 http_server_connection_pipeline_is_full(struct http_server_connection *conn)
 {
 	return (conn->request_queue_count >=
-			conn->server->set.max_pipelined_requests);
+			conn->server->set.max_pipelined_requests ||
+			conn->server->shutting_down);
 }
 
 static void
 http_server_connection_pipeline_handle_full(
 	struct http_server_connection *conn)
 {
-	http_server_connection_debug(conn,
-		"Pipeline full (%u requests pending; %u maximum)",
-		conn->request_queue_count,
-		conn->server->set.max_pipelined_requests);
+	if (conn->server->shutting_down) {
+		http_server_connection_debug(conn,
+			"Pipeline full (%u requests pending; server shutting down)",
+			conn->request_queue_count);
+	} else {
+		http_server_connection_debug(conn,
+			"Pipeline full (%u requests pending; %u maximum)",
+			conn->request_queue_count,
+			conn->server->set.max_pipelined_requests);
+	}
 	http_server_connection_input_halt(conn);
 }
 
@@ -517,6 +534,12 @@ static void http_server_connection_input(struct connection *_conn)
 	bool cont;
 	int ret;
 
+	if (conn->server->shutting_down) {
+		if (!http_server_connection_shut_down(conn))
+			http_server_connection_pipeline_handle_full(conn);
+		return;
+	}
+
 	i_assert(!conn->in_req_callback);
 	i_assert(!conn->input_broken && conn->incoming_payload == NULL);
 	i_assert(!conn->close_indicated);
@@ -881,7 +904,8 @@ static int http_server_connection_send_responses(
 
 	/* accept more requests if possible */
 	if (conn->incoming_payload == NULL &&
-		conn->request_queue_count < conn->server->set.max_pipelined_requests) {
+		conn->request_queue_count < conn->server->set.max_pipelined_requests &&
+		!conn->server->shutting_down) {
 		http_server_connection_input_resume(conn);
 		return 1;
 	}
@@ -947,6 +971,10 @@ int http_server_connection_output(struct http_server_connection *conn)
 		}
 	}
 
+	if (conn->server->shutting_down &&
+		http_server_connection_shut_down(conn))
+		return 1;
+
 	if (!http_server_connection_pipeline_is_full(conn)) {
 		http_server_connection_input_resume(conn);
 		if (pipeline_was_full && conn->conn.io != NULL)
@@ -997,6 +1025,8 @@ http_server_connection_create(struct http_server *server,
 	in_port_t port;
 	const char *name;
 
+	i_assert(!server->shutting_down);
+
 	conn = i_new(struct http_server_connection, 1);
 	conn->refcount = 1;
 	conn->id = id++;
diff --git a/src/lib-http/http-server-private.h b/src/lib-http/http-server-private.h
index 73788bef68..b0a512898b 100644
--- a/src/lib-http/http-server-private.h
+++ b/src/lib-http/http-server-private.h
@@ -139,6 +139,8 @@ struct http_server {
 	struct ssl_iostream_context *ssl_ctx;
 
 	struct connection_list *conn_list;
+
+	unsigned int shutting_down:1;    /* shutting down server */
 };
 
 static inline const char *
@@ -211,6 +213,8 @@ http_server_request_version_equals(struct http_server_request *req,
 
 struct connection_list *http_server_connection_list_init(void);
 
+bool http_server_connection_shut_down(struct http_server_connection *conn);
+
 void http_server_connection_switch_ioloop(struct http_server_connection *conn);
 
 void http_server_connection_write_failed(struct http_server_connection *conn,
diff --git a/src/lib-http/http-server.c b/src/lib-http/http-server.c
index 7f9f28df4f..f036d3326f 100644
--- a/src/lib-http/http-server.c
+++ b/src/lib-http/http-server.c
@@ -69,3 +69,19 @@ void http_server_switch_ioloop(struct http_server *server)
 		http_server_connection_switch_ioloop(conn);
 	}
 }
+
+void http_server_shut_down(struct http_server *server)
+{
+	struct connection *_conn, *_next;
+
+	server->shutting_down = TRUE;
+
+	for (_conn = server->conn_list->connections;
+		_conn != NULL; _conn = _next) {
+		struct http_server_connection *conn =
+			(struct http_server_connection *)_conn;
+
+		_next = _conn->next;
+		(void)http_server_connection_shut_down(conn);
+	}
+}
diff --git a/src/lib-http/http-server.h b/src/lib-http/http-server.h
index b90a396731..53ec3ac521 100644
--- a/src/lib-http/http-server.h
+++ b/src/lib-http/http-server.h
@@ -68,6 +68,9 @@ typedef void (*http_server_tunnel_callback_t)(void *context,
 
 struct http_server *http_server_init(const struct http_server_settings *set);
 void http_server_deinit(struct http_server **_server);
+/* shut down the server; accept no new requests and drop connections once
+   they become idle */
+void http_server_shut_down(struct http_server *server);
 
 struct http_server_connection *
 http_server_connection_create(struct http_server *server,