From: Willy Tarreau <w@1wt.eu>
Date: Sat, 30 Dec 2017 17:08:13 +0000 (+0100)
Subject: MEDIUM: h2: prepare a graceful shutdown when the frontend is stopped
X-Git-Tag: v1.9-dev1~532
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8ec140604acfa15b976285f54755b2cf38552273;p=thirdparty%2Fhaproxy.git

MEDIUM: h2: prepare a graceful shutdown when the frontend is stopped

During a reload operation, instead of keeping the H2 connections opened
forever causing confusion during configuration changes, let's send a
graceful shutdown so that the client knows that it would better open a
new connection for future requests. We can't really catch the signal
from H2, but we can advertise this graceful shutdown upon the next I/O
event (eg: a WINDOW_UPDATE from the client or a new request). One of
the visible effect is that the old process quits much faster.

This patch should be backported to 1.8 since it is affected by this
problem.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 71660f8e8a..c6e15eca85 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -2250,6 +2250,7 @@ static void h2_send(struct connection *conn)
 static int h2_wake(struct connection *conn)
 {
 	struct h2c *h2c = conn->mux_ctx;
+	struct session *sess = conn->owner;
 
 	if (h2c->dbuf->i && !(h2c->flags & H2_CF_DEM_BLOCK_ANY)) {
 		h2_process_demux(h2c);
@@ -2261,6 +2262,18 @@ static int h2_wake(struct connection *conn)
 			h2c->flags &= ~H2_CF_DEM_DFULL;
 	}
 
+	if (sess && unlikely(sess->fe->state == PR_STSTOPPED)) {
+		/* frontend is stopping, reload likely in progress, let's try
+		 * to announce a graceful shutdown if not yet done. We don't
+		 * care if it fails, it will be tried again later.
+		 */
+		if (!(h2c->flags & (H2_CF_GOAWAY_SENT|H2_CF_GOAWAY_FAILED))) {
+			if (h2c->last_sid < 0)
+				h2c->last_sid = (1U << 31) - 1;
+			h2c_send_goaway_error(h2c, NULL);
+		}
+	}
+
 	/*
 	 * If we received early data, try to wake any stream, just in case
 	 * at least one of them was waiting for the handshake