From 89cde43d322e08c41c8ecb3118345fddeda97ffb Mon Sep 17 00:00:00 2001
From: Conor Broderick <conor.broderick@robustperception.io>
Date: Wed, 12 Jul 2017 14:31:37 +0100
Subject: [PATCH] Added metric for http/tcp regex match (#191)

---
 http.go       | 11 +++++++++++
 http_test.go  | 16 ++++++++++++++++
 tcp.go        |  7 +++++++
 tcp_test.go   | 17 +++++++++++++++++
 utils_test.go |  6 +++++-
 5 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/http.go b/http.go
index 8c75d2e..bd1f37a 100644
--- a/http.go
+++ b/http.go
@@ -91,6 +91,11 @@ func probeHTTP(ctx context.Context, target string, module Module, registry *prom
 			Name: "probe_http_version",
 			Help: "Returns the version of HTTP of the probe response",
 		})
+
+		probeFailedDueToRegex = prometheus.NewGauge(prometheus.GaugeOpts{
+			Name: "probe_failed_due_to_regex",
+			Help: "Indicates if probe failed due to regex",
+		})
 	)
 
 	registry.MustRegister(contentLengthGauge)
@@ -98,6 +103,7 @@ func probeHTTP(ctx context.Context, target string, module Module, registry *prom
 	registry.MustRegister(isSSLGauge)
 	registry.MustRegister(statusCodeGauge)
 	registry.MustRegister(probeHTTPVersionGauge)
+	registry.MustRegister(probeFailedDueToRegex)
 
 	httpConfig := module.HTTP
 
@@ -186,6 +192,11 @@ func probeHTTP(ctx context.Context, target string, module Module, registry *prom
 
 		if success && (len(httpConfig.FailIfMatchesRegexp) > 0 || len(httpConfig.FailIfNotMatchesRegexp) > 0) {
 			success = matchRegularExpressions(resp.Body, httpConfig)
+			if success {
+				probeFailedDueToRegex.Set(0)
+			} else {
+				probeFailedDueToRegex.Set(1)
+			}
 		}
 
 		var httpVersionNumber float64
diff --git a/http_test.go b/http_test.go
index f897dfd..eec5c1b 100644
--- a/http_test.go
+++ b/http_test.go
@@ -241,6 +241,14 @@ func TestFailIfMatchesRegexp(t *testing.T) {
 	if result {
 		t.Fatalf("Regexp test succeeded unexpectedly, got %s", body)
 	}
+	mfs, err := registry.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedResults := map[string]float64{
+		"probe_failed_due_to_regex": 1,
+	}
+	checkRegistryResults(expectedResults, mfs, t)
 
 	ts = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintf(w, "Download the latest version here")
@@ -255,6 +263,14 @@ func TestFailIfMatchesRegexp(t *testing.T) {
 	if !result {
 		t.Fatalf("Regexp test failed unexpectedly, got %s", body)
 	}
+	mfs, err = registry.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedResults = map[string]float64{
+		"probe_failed_due_to_regex": 0,
+	}
+	checkRegistryResults(expectedResults, mfs, t)
 
 	// With multiple regexps configured, verify that any matching regexp causes
 	// the probe to fail, but probes succeed when no regexp matches.
diff --git a/tcp.go b/tcp.go
index 4a31387..61dc9fe 100644
--- a/tcp.go
+++ b/tcp.go
@@ -68,6 +68,11 @@ func probeTCP(ctx context.Context, target string, module Module, registry *prome
 		Name: "probe_ssl_earliest_cert_expiry",
 		Help: "Returns earliest SSL cert expiry date",
 	})
+	probeFailedDueToRegex := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "probe_failed_due_to_regex",
+		Help: "Indicates if probe failed due to regex",
+	})
+	registry.MustRegister(probeFailedDueToRegex)
 	deadline := time.Now().Add(module.Timeout)
 	conn, err := dialTCP(ctx, target, module, registry)
 	if err != nil {
@@ -112,8 +117,10 @@ func probeTCP(ctx context.Context, target string, module Module, registry *prome
 				return false
 			}
 			if match == nil {
+				probeFailedDueToRegex.Set(1)
 				return false
 			}
+			probeFailedDueToRegex.Set(0)
 			send = string(re.Expand(nil, []byte(send), scanner.Bytes(), match))
 		}
 		if send != "" {
diff --git a/tcp_test.go b/tcp_test.go
index 222ab06..7c2367c 100644
--- a/tcp_test.go
+++ b/tcp_test.go
@@ -117,6 +117,14 @@ func TestTCPConnectionQueryResponseIRC(t *testing.T) {
 	if probeTCP(testCTX, ln.Addr().String(), module, registry) {
 		t.Fatalf("TCP module succeeded, expected failure.")
 	}
+	mfs, err := registry.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedResults := map[string]float64{
+		"probe_failed_due_to_regex": 1,
+	}
+	checkRegistryResults(expectedResults, mfs, t)
 	<-ch
 }
 
@@ -162,6 +170,15 @@ func TestTCPConnectionQueryResponseMatching(t *testing.T) {
 	if got, want := <-ch, "OpenSSH_6.9p1"; got != want {
 		t.Fatalf("Read unexpected version: got %q, want %q", got, want)
 	}
+	mfs, err := registry.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedResults := map[string]float64{
+		"probe_failed_due_to_regex": 0,
+	}
+	checkRegistryResults(expectedResults, mfs, t)
+
 }
 
 func TestTCPConnectionProtocol(t *testing.T) {
diff --git a/utils_test.go b/utils_test.go
index 1cbc4f0..c121c58 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -13,7 +13,11 @@ func checkRegistryResults(expRes map[string]float64, mfs []*dto.MetricFamily, t
 		res[mfs[i].GetName()] = mfs[i].Metric[0].GetGauge().GetValue()
 	}
 	for k, v := range expRes {
-		if val, ok := res[k]; !ok || val != v {
+		val, ok := res[k]
+		if !ok {
+			t.Fatalf("Expected metric %v not found in returned metrics", k)
+		}
+		if val != v {
 			t.Fatalf("Expected: %v: %v, got: %v: %v", k, v, k, val)
 		}
 	}
-- 
2.25.1