Merge pull request #107 from prometheus/mr/fix-and-test-readme

Fix and test examples in the README

README.md

@@ -83,8 +83,8 @@ starting at 1. Multiple matching definitions are separated by one or more empty
 lines. The first mapping rule that matches a StatsD metric wins.
 
 Metrics that don't match any mapping in the configuration file are translated
-into Prometheus metrics without any labels and with certain characters escaped
-(`_` -> `__`; `-` -> `__`; `.` -> `_`).
+into Prometheus metrics without any labels and with any non-alphanumeric
+characters, including periods, translated into underscores.
 
 In general, the different metric types are translated as follows:
 
@@ -107,7 +107,7 @@ mappings:
     action: "$2"
     outcome: "$3"
     job: "test_dispatcher"
-- match: *.signup.*.*
+- match: "*.signup.*.*"
   labels:
     name: "signup_events_total"
     provider: "$2"
@@ -125,7 +125,7 @@ follows:
      => signup_events_total{provider="facebook", outcome="failure", job="foo_product_server"}
 
     test.web-server.foo.bar
-     => test_web__server_foo_bar{}
+     => test_web_server_foo_bar{}
 
 
 If the default metric help text is insufficient for your needs you may use the YAML

exporter_test.go

@@ -153,3 +153,21 @@ func (ml *mockStatsDTCPListener) handlePacket(packet []byte, e chan<- Events) {
 	}
 	ml.handleConn(sc, e)
 }
+
+func TestEscapeMetricName(t *testing.T) {
+	scenarios := map[string]string{
+		"clean":                   "clean",
+		"0starts_with_digit":      "_0starts_with_digit",
+		"with_underscore":         "with_underscore",
+		"with.dot":                "with_dot",
+		"with😱emoji":              "with_emoji",
+		"with.*.multiple":         "with___multiple",
+		"test.web-server.foo.bar": "test_web_server_foo_bar",
+	}
+
+	for in, want := range scenarios {
+		if got := escapeMetricName(in); want != got {
+			t.Errorf("expected `%s` to be escaped to `%s`, got `%s`", in, want, got)
+		}
+	}
+}

mapper_test.go

@@ -189,6 +189,45 @@ mappings:
 			config:   ``,
 			mappings: map[string]map[string]string{},
 		},
+		// Config without a trailing newline.
+		{
+			config: `mappings:
+- match: test.*
+  labels:
+    name: "name"
+    label: "${1}_foo"`,
+			mappings: map[string]map[string]string{
+				"test.a": map[string]string{
+					"name":  "name",
+					"label": "a_foo",
+				},
+			},
+		},
+		// Config with an improperly escaped *.
+		{
+			config: `
+mappings:
+- match: *.test.*
+  labels:
+    name: "name"
+    label: "${1}_foo"`,
+			configBad: true,
+		},
+		// Config with a properly escaped *.
+		{
+			config: `
+mappings:
+- match: "*.test.*"
+  labels:
+    name: "name"
+    label: "${2}_foo"`,
+			mappings: map[string]map[string]string{
+				"foo.test.a": map[string]string{
+					"name":  "name",
+					"label": "a_foo",
+				},
+			},
+		},
 		// Config with good timer type.
 		{
 			config: `---
@@ -219,13 +258,48 @@ mappings:
 		{
 			config: `---
 mappings:
-- match: *\.foo
+- match: "*\.foo"
   match_type: regex
   labels:
     name: "foo"
     `,
 			configBad: true,
 		},
+		// Example from the README.
+		{
+			config: `
+mappings:
+- match: test.dispatcher.*.*.*
+  labels:
+    name: "dispatcher_events_total"
+    processor: "$1"
+    action: "$2"
+    outcome: "$3"
+    job: "test_dispatcher"
+- match: "*.signup.*.*"
+  labels:
+    name: "signup_events_total"
+    provider: "$2"
+    outcome: "$3"
+    job: "${1}_server"
+`,
+			mappings: map[string]map[string]string{
+				"test.dispatcher.FooProcessor.send.success": map[string]string{
+					"name":      "dispatcher_events_total",
+					"processor": "FooProcessor",
+					"action":    "send",
+					"outcome":   "success",
+					"job":       "test_dispatcher",
+				},
+				"foo_product.signup.facebook.failure": map[string]string{
+					"name":     "signup_events_total",
+					"provider": "facebook",
+					"outcome":  "failure",
+					"job":      "foo_product_server",
+				},
+				"test.web-server.foo.bar": map[string]string{},
+			},
+		},
 	}
 
 	mapper := metricMapper{}