Fix Collector Metrics Prefix

docs/service-extensions.md

@@ -1,6 +1,6 @@
 # OpenTelemetry Collector: Extensions
 
-Besides the pipeline elements (receivers, processors, and exporters) the OTelSvc
+Besides the pipeline elements (receivers, processors, and exporters) the Collector
 uses various service extensions (e.g.: healthcheck, z-pages, etc). 
 This document describes the “extensions” design and how they are implemented.
 
@@ -46,7 +46,7 @@ these sections would look like in the configuration file:
 
 ```yaml
 
-# Example of the extensions provided in OTelSvc core. The list below
+# Example of the extensions available with the core Collector. The list below
 # includes all configurable options and their respective default value.
 extensions:
   health_check:

exporter/README.md

@@ -86,7 +86,7 @@ Exports traces and/or metrics to the console via zap.Logger
 * `loglevel`: the log level of the logging export (debug|info|warn|error). Default is `info`.
 
 ## <a name="opencensus"></a>OpenCensus
-Exports traces and/or metrics to another OTel-Svc endpoint via gRPC.
+Exports traces and/or metrics to another Collector via gRPC using OpenCensus format.
 
 ### <a name="opencensus-configuration"></a>Configuration
 

observability/observability.go

@@ -131,7 +131,7 @@ var AllViews = []*view.View{
 	ViewExporterDroppedTimeSeries,
 }
 
-// ContextWithReceiverName adds the tag "otelsvc_receiver" and the name of the receiver as the value,
+// ContextWithReceiverName adds the tag "receiver" and the name of the receiver as the value,
 // and returns the newly created context. For receivers that can receive multiple signals it is
 // recommended to encode the signal as suffix (e.g. "oc_trace" and "oc_metrics").
 func ContextWithReceiverName(ctx context.Context, receiverName string) context.Context {
@@ -151,7 +151,7 @@ func RecordMetricsForMetricsReceiver(ctxWithTraceReceiverName context.Context, r
 	stats.Record(ctxWithTraceReceiverName, mReceiverReceivedTimeSeries.M(int64(receivedTimeSeries)), mReceiverDroppedTimeSeries.M(int64(droppedTimeSeries)))
 }
 
-// ContextWithExporterName adds the tag "otelsvc_exporter" and the name of the exporter as the value,
+// ContextWithExporterName adds the tag "exporter" and the name of the exporter as the value,
 // and returns the newly created context. For exporters that can export multiple signals it is
 // recommended to encode the signal as suffix (e.g. "oc_trace" and "oc_metrics").
 func ContextWithExporterName(ctx context.Context, exporterName string) context.Context {

service/service_test.go

@@ -16,8 +16,12 @@
 package service
 
 import (
+	"bufio"
+	"fmt"
+	"io"
 	"net/http"
 	"strconv"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -38,27 +42,25 @@ func TestApplication_Start(t *testing.T) {
 	app, err := New(factories, ApplicationStartInfo{})
 	require.NoError(t, err)
 
+	const testPrefix = "a_test"
 	metricsPort := testutils.GetAvailablePort(t)
 	app.rootCmd.SetArgs([]string{
 		"--config=testdata/otelcol-config.yaml",
 		"--metrics-port=" + strconv.FormatUint(uint64(metricsPort), 10),
+		"--metrics-prefix=" + testPrefix,
 	})
 
 	appDone := make(chan struct{})
 	go func() {
 		defer close(appDone)
-		if err := app.Start(); err != nil {
-			t.Errorf("app.Start() got %v, want nil", err)
-			return
-		}
+		assert.NoError(t, app.Start())
 	}()
 
 	<-app.readyChan
 
-	// TODO: Add a way to change configuration files so we can get the ports dynamically
-	if !isAppAvailable(t, "http://localhost:13133") {
-		t.Fatalf("app didn't reach ready state")
-	}
+	require.True(t, isAppAvailable(t, "http://localhost:13133"))
+
+	assertMetricsPrefix(t, testPrefix, metricsPort)
 
 	close(app.stopTestChan)
 	<-appDone
@@ -69,13 +71,42 @@ func TestApplication_Start(t *testing.T) {
 func isAppAvailable(t *testing.T, healthCheckEndPoint string) bool {
 	client := &http.Client{}
 	resp, err := client.Get(healthCheckEndPoint)
-	if err != nil {
-		t.Fatalf("failed to get a response from health probe: %v", err)
-	}
+	require.NoError(t, err)
+
 	defer resp.Body.Close()
 	return resp.StatusCode == http.StatusOK
 }
 
+func assertMetricsPrefix(t *testing.T, prefix string, metricsPort uint16) {
+	client := &http.Client{}
+	resp, err := client.Get(fmt.Sprintf("http://localhost:%d/metrics", metricsPort))
+	require.NoError(t, err)
+
+	defer resp.Body.Close()
+	reader := bufio.NewReader(resp.Body)
+
+	for {
+		s, err := reader.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+
+		require.NoError(t, err)
+		if len(s) == 0 || s[0] == '#' {
+			// Skip this line since it is not a metric.
+			continue
+		}
+
+		// require is used here so test fails with a single message.
+		require.True(
+			t,
+			strings.HasPrefix(s, prefix),
+			"expected prefix %q but string starts with %q",
+			prefix,
+			s[:len(prefix)+1]+"...")
+	}
+}
+
 func TestApplication_setupExtensions(t *testing.T) {
 	exampleExtensionFactory := &config.ExampleExtensionFactory{}
 	exampleExtensionConfig := &config.ExampleExtension{

service/telemetry.go

@@ -33,27 +33,42 @@ import (
 )
 
 const (
-	metricsPortCfg  = "metrics-port"
-	metricsLevelCfg = "metrics-level"
+	metricsPortCfg   = "metrics-port"
+	metricsLevelCfg  = "metrics-level"
+	metricsPrefixCfg = "metrics-prefix"
 )
 
 var (
 	// AppTelemetry is application's own telemetry.
 	AppTelemetry = &appTelemetry{}
 
 	// Command-line flags that control publication of telemetry data.
-	metricsLevelPtr *string
-	metricsPortPtr  *uint
+	metricsLevelPtr  *string
+	metricsPortPtr   *uint
+	metricsPrefixPtr *string
 )
 
 type appTelemetry struct {
 	views []*view.View
 }
 
 func telemetryFlags(flags *flag.FlagSet) {
-	metricsLevelPtr = flags.String(metricsLevelCfg, "BASIC", "Output level of telemetry metrics (NONE, BASIC, NORMAL, DETAILED)")
-	// At least until we can use a generic, i.e.: OpenCensus, metrics exporter we default to Prometheus at port 8888, if not otherwise specified.
-	metricsPortPtr = flags.Uint(metricsPortCfg, 8888, "Port exposing collector telemetry.")
+	metricsLevelPtr = flags.String(
+		metricsLevelCfg,
+		"BASIC",
+		"Output level of telemetry metrics (NONE, BASIC, NORMAL, DETAILED)")
+
+	// At least until we can use a generic, i.e.: OpenCensus, metrics exporter
+	// we default to Prometheus at port 8888, if not otherwise specified.
+	metricsPortPtr = flags.Uint(
+		metricsPortCfg,
+		8888,
+		"Port exposing collector telemetry.")
+
+	metricsPrefixPtr = flags.String(
+		metricsPrefixCfg,
+		"otelcol",
+		"Prefix to the metrics generated by the collector.")
 }
 
 func (tel *appTelemetry) init(asyncErrorChannel chan<- error, ballastSizeBytes uint64, logger *zap.Logger) error {
@@ -84,7 +99,7 @@ func (tel *appTelemetry) init(asyncErrorChannel chan<- error, ballastSizeBytes u
 
 	// Until we can use a generic metrics exporter, default to Prometheus.
 	opts := prometheus.Options{
-		Namespace: "oc_collector",
+		Namespace: *metricsPrefixPtr,
 	}
 	pe, err := prometheus.NewExporter(opts)
 	if err != nil {