mirror of
https://github.com/open-telemetry/opentelemetry-go.git
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fdfc821bac
Comment should be complete sentences outside of lists with sentence fragments. This adds the godot linter to check these complete sentences end with punctuation. If they do not, running fix will append a period.
90 lines
3.3 KiB
Go
90 lines
3.3 KiB
Go
// Copyright The 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"
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"go.opentelemetry.io/otel/example/passthrough/handler"
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"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
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"go.opentelemetry.io/otel/propagation"
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sdktrace "go.opentelemetry.io/otel/sdk/trace"
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"go.opentelemetry.io/otel/trace"
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)
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func main() {
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ctx := context.Background()
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initPassthroughGlobals()
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tp := nonGlobalTracer()
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defer func() { _ = tp.Shutdown(ctx) }()
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// make an initial http request
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r, err := http.NewRequest("", "", nil)
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if err != nil {
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panic(err)
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}
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// This is roughly what an instrumented http client does.
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log.Println("The \"make outer request\" span should be recorded, because it is recorded with a Tracer from the SDK TracerProvider")
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var span trace.Span
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ctx, span = tp.Tracer("example/passthrough/outer").Start(ctx, "make outer request")
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defer span.End()
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r = r.WithContext(ctx)
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otel.GetTextMapPropagator().Inject(ctx, propagation.HeaderCarrier(r.Header))
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backendFunc := func(r *http.Request) {
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// This is roughly what an instrumented http server does.
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ctx := otel.GetTextMapPropagator().Extract(r.Context(), propagation.HeaderCarrier(r.Header))
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log.Println("The \"handle inner request\" span should be recorded, because it is recorded with a Tracer from the SDK TracerProvider")
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_, span := tp.Tracer("example/passthrough/inner").Start(ctx, "handle inner request")
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defer span.End()
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// Do "backend work"
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time.Sleep(time.Second)
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}
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// This handler will be a passthrough, since we didn't set a global TracerProvider
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passthroughHandler := handler.New(backendFunc)
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passthroughHandler.HandleHTTPReq(r)
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}
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func initPassthroughGlobals() {
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// We explicitly DO NOT set the global TracerProvider using otel.SetTracerProvider().
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// The unset TracerProvider returns a "non-recording" span, but still passes through context.
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log.Println("Register a global TextMapPropagator, but do not register a global TracerProvider to be in \"passthrough\" mode.")
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log.Println("The \"passthrough\" mode propagates the TraceContext and Baggage, but does not record spans.")
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otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
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}
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// nonGlobalTracer creates a trace provider instance for testing, but doesn't
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// set it as the global tracer provider.
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func nonGlobalTracer() *sdktrace.TracerProvider {
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var err error
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exp, err := stdouttrace.New(stdouttrace.WithPrettyPrint())
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if err != nil {
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log.Panicf("failed to initialize stdouttrace exporter %v\n", err)
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}
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bsp := sdktrace.NewBatchSpanProcessor(exp)
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tp := sdktrace.NewTracerProvider(
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sdktrace.WithSampler(sdktrace.AlwaysSample()),
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sdktrace.WithSpanProcessor(bsp),
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)
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return tp
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}
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