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opentelemetry-go/example/passthrough/main.go
Anthony Mirabella c30cd1d0fd
Split stdout exporter into stdouttrace and stdoutmetric (#2005)
* Split stdout exporter into stdouttrace and stdoutmetric

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Remove unused options from stdouttrace and stdoutmetric exporters

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Update stdout exporter references in website docs

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Update docs to include correct import paths, properly describe exporter scope

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Remove pointless options to disable signals from what are now single-signal exporters

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>
2021-06-16 11:32:42 -04:00

90 lines
3.3 KiB
Go

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