Make it possible to configure the number of retries the random director

will make at getting a backend connection.  By default it tries as many
times as it has members.



git-svn-id: http://www.varnish-cache.org/svn/trunk@3138 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_dir_random.c

@@ -57,6 +57,8 @@ struct vdi_random {
 	unsigned		magic;
 #define VDI_RANDOM_MAGIC	0x3771ae23
 	struct director		dir;
+
+	unsigned		retries;
 	struct vdi_random_host	*hosts;
 	unsigned		nhosts;
 };
@@ -74,7 +76,7 @@ vdi_random_getfd(struct sess *sp)
 	CAST_OBJ_NOTNULL(vs, sp->director->priv, VDI_RANDOM_MAGIC);
 
 	k = 0;
-	for (k = 0; k < 4; ) {	/* XXX: 4 is arbitrary */
+	for (k = 0; k < vs->retries; ) {
 
 		r = random() / 2147483648.0;	/* 2^31 */
 		assert(r >= 0.0 && r < 1.0);
@@ -143,7 +145,6 @@ VRT_init_dir_random(struct cli *cli, struct director **bp, const struct vrt_dir_
 	struct vdi_random *vs;
 	const struct vrt_dir_random_entry *te;
 	struct vdi_random_host *vh;
-	double s;
 	int i;
 	
 	(void)cli;
@@ -159,7 +160,9 @@ VRT_init_dir_random(struct cli *cli, struct director **bp, const struct vrt_dir_
 	vs->dir.getfd = vdi_random_getfd;
 	vs->dir.fini = vdi_random_fini;
 
-	s = 0;
+	vs->retries = t->retries;
+	if (vs->retries == 0)
+		vs->retries = t->nmember;
 	vh = vs->hosts;
 	te = t->members;
 	for (i = 0; i < t->nmember; i++, vh++, te++) {

include/vrt.h

@@ -93,6 +93,7 @@ struct vrt_dir_random_entry {
 
 struct vrt_dir_random {
 	const char 				*name;
+	unsigned				retries;
 	unsigned 				nmember;
 	const struct vrt_dir_random_entry	*members;
 };

lib/libvcl/vcc_dir_random.c

@@ -54,11 +54,29 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 {
 	struct token *t_field, *t_be;
 	int nbh, nelem;
-	struct fld_spec *fs;
-	unsigned u;
+	struct fld_spec *fs, *mfs;
+	unsigned u, retries;
 	const char *first;
 
-	fs = vcc_FldSpec(tl, "!backend", "!weight", NULL);
+	fs = vcc_FldSpec(tl, "?retries", NULL);
+
+	retries = 0;
+	while (tl->t->tok != '{') {
+		vcc_IsField(tl, &t_field, fs);
+		ERRCHK(tl);
+		if (vcc_IdIs(t_field, "retries")) {
+			ExpectErr(tl, CNUM);
+			retries = vcc_UintVal(tl);
+			ERRCHK(tl);
+			vcc_NextToken(tl);
+			ExpectErr(tl, ';');
+			vcc_NextToken(tl);
+		} else {
+			ErrInternal(tl);
+		}
+	}
+
+	mfs = vcc_FldSpec(tl, "!backend", "!weight", NULL);
 
 	Fc(tl, 0,
 	    "\nstatic const struct vrt_dir_random_entry vdre_%.*s[] = {\n",
@@ -67,7 +85,7 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 	for (nelem = 0; tl->t->tok != '}'; nelem++) {	/* List of members */
 		first = "";
 		t_be = tl->t;
-		vcc_ResetFldSpec(fs);
+		vcc_ResetFldSpec(mfs);
 		nbh = -1;
 
 		ExpectErr(tl, '{');
@@ -75,7 +93,7 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 		Fc(tl, 0, "\t{");
 	
 		while (tl->t->tok != '}') {	/* Member fields */
-			vcc_IsField(tl, &t_field, fs);
+			vcc_IsField(tl, &t_field, mfs);
 			ERRCHK(tl);
 			if (vcc_IdIs(t_field, "backend")) {
 				vcc_ParseBackendHost(tl, &nbh,
@@ -85,6 +103,7 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 			} else if (vcc_IdIs(t_field, "weight")) {
 				ExpectErr(tl, CNUM);
 				u = vcc_UintVal(tl);
+				ERRCHK(tl);
 				if (u == 0) {
 					vsb_printf(tl->sb,
 					    "The .weight must be higher "
@@ -103,7 +122,7 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 			}
 			first = ", ";
 		}
-		vcc_FieldsOk(tl, fs);
+		vcc_FieldsOk(tl, mfs);
 		if (tl->err) {
 			vsb_printf(tl->sb,
 			    "\nIn member host specfication starting at:\n");
@@ -118,6 +137,7 @@ vcc_ParseRandomDirector(struct tokenlist *tl, const struct token *t_policy, cons
 	    "\nstatic const struct vrt_dir_random vdr_%.*s = {\n",
 	    PF(t_dir));
 	Fc(tl, 0, "\t.name = \"%.*s\",\n", PF(t_dir));
+	Fc(tl, 0, "\t.retries = %u,\n", retries);
 	Fc(tl, 0, "\t.nmember = %d,\n", nelem);
 	Fc(tl, 0, "\t.members = vdre_%.*s,\n", PF(t_dir));
 	Fc(tl, 0, "};\n");

lib/libvcl/vcc_fixed_token.c

@@ -373,6 +373,7 @@ vcl_output_lang_h(struct vsb *sb)
 	vsb_cat(sb, "\n");
 	vsb_cat(sb, "struct vrt_dir_random {\n");
 	vsb_cat(sb, "	const char 				*name;\n");
+	vsb_cat(sb, "	unsigned				retries;\n");
 	vsb_cat(sb, "	unsigned 				nmember;\n");
 	vsb_cat(sb, "	const struct vrt_dir_random_entry	*members;\n");
 	vsb_cat(sb, "};\n");