Add a new backend attribute in VCL: "connect_timeout".

This is how long time we wait for a TCP connection to the backend to
become established.

Typical usage:

		backend b1 {
			.host = "hex";
			.port = "80";
			.connect_timeout = 500 ms;
		}

It can also be used in backends in director declarations.

Also add a parameter called "connect_timeout" which sets the default
to 400 msec (a number pulled out of my old black magicians hat).




git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@2642 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_backend.c

@@ -150,7 +150,7 @@ VBE_TryConnect(const struct sess *sp, const struct addrinfo *ai)
 	struct sockaddr_storage ss;
 	int fam, sockt, proto;
 	socklen_t alen;
-	int s;
+	int s, i, tmo;
 	char abuf1[TCP_ADDRBUFSIZE], abuf2[TCP_ADDRBUFSIZE];
 	char pbuf1[TCP_PORTBUFSIZE], pbuf2[TCP_PORTBUFSIZE];
 
@@ -177,7 +177,16 @@ VBE_TryConnect(const struct sess *sp, const struct addrinfo *ai)
 		return (s);
 	}
 
-	if (connect(s, (void *)&ss, alen) != 0) {
+	tmo = params->connect_timeout;
+	if (sp->backend->vrt->connect_timeout > 10e-3)
+		tmo = sp->backend->vrt->connect_timeout * 1000;
+
+	if (tmo > 0)
+		i = TCP_connect(s, (void *)&ss, alen, tmo);
+	else
+		i = connect(s, (void *)&ss, alen);
+
+	if (i != 0) {
 		AZ(close(s));
 		LOCK(&sp->backend->mtx);
 		return (-1);

bin/varnishd/heritage.h

@@ -140,6 +140,9 @@ struct params {
 	/* Cache vbe_conns */
 	unsigned		cache_vbe_conns;
 
+	/* Default connection_timeout */
+	unsigned		connect_timeout;
+
 	/* CLI buffer size */
 	unsigned		cli_buffer;
 

bin/varnishd/mgt_param.c

@@ -639,6 +639,14 @@ static const struct parspec parspec[] = {
 		"Cache vbe_conn's or rely on malloc, that's the question.",
 		EXPERIMENTAL,
 		"off", "bool" },
+	{ "connect_timeout", tweak_uint,
+		&master.connect_timeout,0, UINT_MAX,
+		"Default connection timeout for backend connections.  "
+		"We only try to connect to the backend for this many "
+		"milliseconds before giving up.  "
+		"VCL can override this default value for each backend.",
+		0,
+		"400", "ms" },
 	{ "cli_buffer", tweak_uint, &master.cli_buffer, 4096, UINT_MAX,
 		"Size of buffer for CLI input."
 		"\nYou may need to increase this if you have big VCL files "

include/vrt.h

@@ -49,6 +49,7 @@ struct vrt_backend {
 	const char	*hostname;
 	const char	*vcl_name;
 	const char	*ident;
+	double		connect_timeout;
 };
 
 /*

lib/libvcl/vcc_backend.c

@@ -223,7 +223,7 @@ vcc_ParseBackendHost(struct tokenlist *tl, int *nbh, const struct token *qual, i
 	struct host *h;
 	struct fld_spec *fs;
 
-	fs = vcc_FldSpec(tl, "!host", "?port", NULL);
+	fs = vcc_FldSpec(tl, "!host", "?port", "?connect_timeout", NULL);
 	t_first = tl->t;
 
 	if (tl->t->tok == ID) {
@@ -273,10 +273,16 @@ vcc_ParseBackendHost(struct tokenlist *tl, int *nbh, const struct token *qual, i
 			t_host = tl->t;
 			vcc_NextToken(tl);
 		} else if (vcc_IdIs(t_field, "port")) {
-			ExpectErr(tl, CSTR);
 			assert(tl->t->dec != NULL);
 			t_port = tl->t;
 			vcc_NextToken(tl);
+		} else if (vcc_IdIs(t_field, "connect_timeout")) {
+			Fh(tl, 0, "\t.connect_timeout = ");
+			tl->fb = tl->fh;
+			vcc_TimeVal(tl);
+			tl->fb = NULL;
+			ERRCHK(tl);
+			Fh(tl, 0, ",\n");
 		} else {
 			ErrInternal(tl);
 			return;

lib/libvcl/vcc_fixed_token.c

@@ -403,6 +403,7 @@ vcl_output_lang_h(struct vsb *sb)
 	vsb_cat(sb, "	const char	*hostname;\n");
 	vsb_cat(sb, "	const char	*vcl_name;\n");
 	vsb_cat(sb, "	const char	*ident;\n");
+	vsb_cat(sb, "	double		connect_timeout;\n");
 	vsb_cat(sb, "};\n");
 	vsb_cat(sb, "\n");
 	vsb_cat(sb, "/*\n");