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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-12 10:04:29 +02:00
opentelemetry-go/example/passthrough/main.go
Tyler Yahn 1f5b159161
Use already enabled revive linter and add depguard (#2883)
* Refactor golangci-lint conf

Order settings alphabetically.

* Add revive settings to golangci conf

* Check blank imports

* Check bool-literal-in-expr

* Check constant-logical-expr

* Check context-as-argument

* Check context-key-type

* Check deep-exit

* Check defer

* Check dot-imports

* Check duplicated-imports

* Check early-return

* Check empty-block

* Check empty-lines

* Check error-naming

* Check error-return

* Check error-strings

* Check errorf

* Stop ignoring context first arg in tests

* Check exported comments

* Check flag-parameter

* Check identical branches

* Check if-return

* Check increment-decrement

* Check indent-error-flow

* Check deny list of go imports

* Check import shadowing

* Check package comments

* Check range

* Check range val in closure

* Check range val address

* Check redefines builtin id

* Check string-format

* Check struct tag

* Check superfluous else

* Check time equal

* Check var naming

* Check var declaration

* Check unconditional recursion

* Check unexported return

* Check unhandled errors

* Check unnecessary stmt

* Check unnecessary break

* Check waitgroup by value

* Exclude deep-exit check in example*_test.go files
2022-05-19 15:15:07 -05:00

93 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"
"fmt"
"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, err := nonGlobalTracer()
if err != nil {
log.Fatal(err)
}
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, error) {
exp, err := stdouttrace.New(stdouttrace.WithPrettyPrint())
if err != nil {
return nil, fmt.Errorf("failed to initialize stdouttrace exporter: %w", err)
}
bsp := sdktrace.NewBatchSpanProcessor(exp)
tp := sdktrace.NewTracerProvider(
sdktrace.WithSampler(sdktrace.AlwaysSample()),
sdktrace.WithSpanProcessor(bsp),
)
return tp, nil
}