2019-11-26 21:47:15 +02:00
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// Copyright 2019, OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"context"
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"log"
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"net/http"
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"time"
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"go.opentelemetry.io/otel/api/global"
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"go.opentelemetry.io/otel/api/key"
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"go.opentelemetry.io/otel/api/metric"
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"go.opentelemetry.io/otel/exporter/metric/prometheus"
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sdkmetric "go.opentelemetry.io/otel/sdk/metric"
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"go.opentelemetry.io/otel/sdk/metric/batcher/defaultkeys"
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"go.opentelemetry.io/otel/sdk/metric/controller/push"
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"go.opentelemetry.io/otel/sdk/metric/selector/simple"
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)
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var (
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fooKey = key.New("ex.com/foo")
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barKey = key.New("ex.com/bar")
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lemonsKey = key.New("ex.com/lemons")
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)
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func initMeter() *push.Controller {
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selector := simple.NewWithExactMeasure()
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2019-12-23 19:47:51 +02:00
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exporter, err := prometheus.NewExporter(prometheus.Options{})
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2019-11-26 21:47:15 +02:00
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if err != nil {
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log.Panicf("failed to initialize metric stdout exporter %v", err)
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}
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2019-12-23 19:47:51 +02:00
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// Prometheus needs to use a stateful batcher since counters (and histogram since they are a collection of Counters)
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// are cumulative (i.e., monotonically increasing values) and should not be resetted after each export.
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//
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// Prometheus uses this approach to be resilient to scrape failures.
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// If a Prometheus server tries to scrape metrics from a host and fails for some reason,
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// it could try again on the next scrape and no data would be lost, only resolution.
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//
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// Gauges (or LastValues) and Summaries are an exception to this and have different behaviors.
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batcher := defaultkeys.New(selector, sdkmetric.NewDefaultLabelEncoder(), true)
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2019-11-26 21:47:15 +02:00
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pusher := push.New(batcher, exporter, time.Second)
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pusher.Start()
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go func() {
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_ = http.ListenAndServe(":2222", exporter)
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}()
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global.SetMeterProvider(pusher)
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return pusher
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}
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func main() {
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defer initMeter().Stop()
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meter := global.MeterProvider().Meter("ex.com/basic")
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oneMetric := meter.NewFloat64Gauge("ex.com.one",
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metric.WithKeys(fooKey, barKey, lemonsKey),
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metric.WithDescription("A gauge set to 1.0"),
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)
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measureTwo := meter.NewFloat64Measure("ex.com.two", metric.WithKeys(key.New("A")))
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measureThree := meter.NewFloat64Counter("ex.com.three")
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commonLabels := meter.Labels(lemonsKey.Int(10), key.String("A", "1"), key.String("B", "2"), key.String("C", "3"))
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notSoCommonLabels := meter.Labels(lemonsKey.Int(13))
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ctx := context.Background()
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meter.RecordBatch(
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ctx,
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commonLabels,
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oneMetric.Measurement(1.0),
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measureTwo.Measurement(2.0),
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measureThree.Measurement(12.0),
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)
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meter.RecordBatch(
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ctx,
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notSoCommonLabels,
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oneMetric.Measurement(1.0),
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measureTwo.Measurement(2.0),
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measureThree.Measurement(22.0),
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)
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time.Sleep(5 * time.Second)
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meter.RecordBatch(
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ctx,
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commonLabels,
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oneMetric.Measurement(13.0),
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measureTwo.Measurement(12.0),
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measureThree.Measurement(13.0),
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)
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time.Sleep(100 * time.Second)
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}
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