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d3b1280863
* Add passthrough example * Update example/passthrough/handler/handler.go Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com> * Update example/passthrough/README.md Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com> * Apply suggestions from code review Co-authored-by: Robert Pająk <pellared@hotmail.com> Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com> Co-authored-by: Robert Pająk <pellared@hotmail.com>
76 lines
2.5 KiB
Go
76 lines
2.5 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 handler
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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/propagation"
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"go.opentelemetry.io/otel/trace"
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)
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// Handler is a minimal implementation of the handler and client from
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// go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp for demonstration purposes.
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// It handles an incoming http request, and makes an outgoing http request.
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type Handler struct {
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propagators propagation.TextMapPropagator
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tracer trace.Tracer
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next func(r *http.Request)
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}
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func New(next func(r *http.Request)) *Handler {
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// Like most instrumentation packages, this handler defaults to using the
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// global progatators and tracer providers.
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return &Handler{
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propagators: otel.GetTextMapPropagator(),
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tracer: otel.Tracer("examples/passthrough/handler"),
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next: next,
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}
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}
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// HandleHTTPReq mimics what an instrumented http server does
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func (h *Handler) HandleHTTPReq(r *http.Request) {
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ctx := h.propagators.Extract(r.Context(), propagation.HeaderCarrier(r.Header))
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var span trace.Span
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log.Println("The \"handle passthrough request\" span should NOT be recorded, because it is recorded by a TracerProvider not backed by the SDK.")
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ctx, span = h.tracer.Start(ctx, "handle passthrough request")
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defer span.End()
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// Pretend to do work
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time.Sleep(time.Second)
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h.makeOutgoingRequest(ctx)
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}
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// makeOutgoingRequest mimics what an instrumented http client does
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func (h *Handler) makeOutgoingRequest(ctx context.Context) {
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// make a new 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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log.Println("The \"make outgoing request from passthrough\" span should NOT be recorded, because it is recorded by a TracerProvider not backed by the SDK.")
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ctx, span := h.tracer.Start(ctx, "make outgoing request from passthrough")
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defer span.End()
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r = r.WithContext(ctx)
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h.propagators.Inject(ctx, propagation.HeaderCarrier(r.Header))
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h.next(r)
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}
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