Implement parsing of .window and .threshold in backend polling specifications.

.window is how many of the latest polls we examine.
.threshold is how many must have succeeded for the backend to be healthy.

	.window = 40;
	.threshold = 30;
		// Thirty of the last fourty polls must have succeed.

	.threshold = 4;
		// The last four polls must have succeeded.

Default values:
	.window = 8;
	.threshold = 3;



git-svn-id: http://www.varnish-cache.org/svn/trunk@3098 d4fa192b-c00b-0410-8231-f00ffab90ce4

include/vrt.h

@@ -51,6 +51,8 @@ struct vrt_backend_probe {
 	char		*request;
 	double		timeout;
 	double		interval;
+	unsigned	window;
+	unsigned	threshold;
 };
 
 /*

lib/libvcl/vcc_backend.c

@@ -336,18 +336,23 @@ vcc_ParseProbe(struct tokenlist *tl)
 {
 	struct fld_spec *fs;
 	struct token *t_field;
-	struct token *t_did = NULL;
+	struct token *t_did = NULL, *t_window = NULL, *t_threshold = NULL;
+	unsigned window, threshold;
 
 	fs = vcc_FldSpec(tl,
 	    "?url",
 	    "?request",
 	    "?timeout",
 	    "?interval",
+	    "?window",
+	    "?threshold",
 	    NULL);
 
 	ExpectErr(tl, '{');
 	vcc_NextToken(tl);
 
+	window = 8;
+	threshold = 3;
 	Fb(tl, 0, "\t.probe = {\n");
 	while (tl->t->tok != '}') {
 
@@ -388,6 +393,16 @@ vcc_ParseProbe(struct tokenlist *tl)
 			vcc_TimeVal(tl);
 			ERRCHK(tl);
 			Fb(tl, 0, ",\n");
+		} else if (vcc_IdIs(t_field, "window")) {
+			t_window = tl->t;
+			window = vcc_UintVal(tl);
+			vcc_NextToken(tl);
+			ERRCHK(tl);
+		} else if (vcc_IdIs(t_field, "threshold")) {
+			t_threshold = tl->t;
+			threshold = vcc_UintVal(tl);
+			vcc_NextToken(tl);
+			ERRCHK(tl);
 		} else {
 			vcc_ErrToken(tl, t_field);
 			vcc_ErrWhere(tl, t_field);
@@ -398,6 +413,33 @@ vcc_ParseProbe(struct tokenlist *tl)
 		ExpectErr(tl, ';');
 		vcc_NextToken(tl);
 	}
+
+	if (t_threshold == NULL && t_window != NULL) {
+		vsb_printf(tl->sb, "Must specify .threshold with .window\n");
+		vcc_ErrWhere(tl, t_window);
+		return;
+	} else if (t_threshold != NULL && t_window == NULL) {
+		if (threshold > 64) {
+			vsb_printf(tl->sb, "Threshold must be 64 or less.\n");
+			vcc_ErrWhere(tl, t_threshold);
+			return;
+		}
+		window = threshold + 1;
+	} else if (window > 64) {
+		AN(t_window);
+		vsb_printf(tl->sb, "Window must be 64 or less.\n");
+		vcc_ErrWhere(tl, t_window);
+		return;
+	}
+	if (threshold > window ) {
+		vsb_printf(tl->sb,
+		    "Threshold can not be greater than window.\n");
+		vcc_ErrWhere(tl, t_threshold);
+		AN(t_window);
+		vcc_ErrWhere(tl, t_window);
+	}
+	Fb(tl, 0, "\t\t.window = %u,\n", window);
+	Fb(tl, 0, "\t\t.threshold = %u\n", threshold);
 	Fb(tl, 0, "\t},\n");
 	ExpectErr(tl, '}');
 	vcc_NextToken(tl);

lib/libvcl/vcc_fixed_token.c

@@ -331,6 +331,8 @@ vcl_output_lang_h(struct vsb *sb)
 	vsb_cat(sb, "	char		*request;\n");
 	vsb_cat(sb, "	double		timeout;\n");
 	vsb_cat(sb, "	double		interval;\n");
+	vsb_cat(sb, "	unsigned	window;\n");
+	vsb_cat(sb, "	unsigned	threshold;\n");
 	vsb_cat(sb, "};\n");
 	vsb_cat(sb, "\n");
 	vsb_cat(sb, "/*\n");

lib/libvcl/vcc_gen_fixed_token.tcl

@@ -214,6 +214,7 @@ warns $foh
 puts $fo "#include \"config.h\""
 puts $fo "#include <stdio.h>"
 puts $fo "#include <ctype.h>"
+puts $fo "#include \"config.h\""
 puts $fo "#include \"vcc_priv.h\""
 puts $fo "#include \"vsb.h\""