exporter/prometheusexporter: migrate code in here

exporter/prometheusexporter/example_test.go

@@ -0,0 +1,108 @@
+// Copyright 2019, OpenCensus Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheusexporter_test
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/census-instrumentation/opencensus-service/exporter/prometheusexporter"
+
+	metricspb "github.com/census-instrumentation/opencensus-proto/gen-go/metrics/v1"
+	"github.com/golang/protobuf/ptypes/timestamp"
+)
+
+func Example() {
+	pe, err := prometheusexporter.New(prometheusexporter.Options{})
+	if err != nil {
+		log.Fatalf("Failed to create new exporter: %v", err)
+	}
+
+	mux := http.NewServeMux()
+	// Expose the Prometheus Metrics exporter for scraping on route /metrics.
+	mux.Handle("/metrics", pe)
+
+	// Now run the server.
+	go func() {
+		http.ListenAndServe(":8888", mux)
+	}()
+
+	// And finally in your client application, use the
+	// OpenCensus-Go Metrics Prometheus exporter to record metrics.
+	for {
+		pe.ExportMetric(context.Background(), nil, nil, metric1)
+		// Introducing a fake pause/period.
+		<-time.After(350 * time.Millisecond)
+	}
+}
+
+var (
+	startTimestamp = &timestamp.Timestamp{
+		Seconds: 1543160298,
+		Nanos:   100000090,
+	}
+	endTimestamp = &timestamp.Timestamp{
+		Seconds: 1543160298,
+		Nanos:   100000997,
+	}
+)
+
+var metric1 = &metricspb.Metric{
+	Descriptor_: &metricspb.Metric_MetricDescriptor{
+		MetricDescriptor: &metricspb.MetricDescriptor{
+			Name:        "this/one/there(where)",
+			Description: "Extra ones",
+			Unit:        "1",
+			LabelKeys: []*metricspb.LabelKey{
+				{Key: "os", Description: "Operating system"},
+				{Key: "arch", Description: "Architecture"},
+			},
+		},
+	},
+	Timeseries: []*metricspb.TimeSeries{
+		{
+			StartTimestamp: startTimestamp,
+			LabelValues: []*metricspb.LabelValue{
+				{Value: "windows"},
+				{Value: "x86"},
+			},
+			Points: []*metricspb.Point{
+				{
+					Timestamp: endTimestamp,
+					Value: &metricspb.Point_Int64Value{
+						Int64Value: 99,
+					},
+				},
+			},
+		},
+		{
+			StartTimestamp: startTimestamp,
+			LabelValues: []*metricspb.LabelValue{
+				{Value: "darwin"},
+				{Value: "386"},
+			},
+			Points: []*metricspb.Point{
+				{
+					Timestamp: endTimestamp,
+					Value: &metricspb.Point_DoubleValue{
+						DoubleValue: 49.5,
+					},
+				},
+			},
+		},
+	},
+}