go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.19.0: New, WithWriter, WithPrettyPrint

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:375ce40d6c3edf2da2694eab0285969a313d30cf103beae50ed2ec3a19fd682b","contract":["stdoutlog.New creates a stdout log exporter with custom writer and configuration options","LoggerProvider with stdoutlog exporter formats and emits log records to the configured writer","exporter.Shutdown cleanly shuts down the stdoutlog exporter"],"goal":"verify pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0"],"schemaVersion":1,"symbols":["stdoutlog.New","stdoutlog.WithWriter","stdoutlog.WithPrettyPrint","stdoutlog.WithoutTimestamps"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0","symbols":["stdoutlog.New","stdoutlog.WithWriter","stdoutlog.WithPrettyPrint","stdoutlog.WithoutTimestamps"],"verifierAdapter":"golang@1"}

package sample

import (
	"context"
	"fmt"
	"io"

	"go.opentelemetry.io/otel/exporters/stdout/stdoutlog"
	"go.opentelemetry.io/otel/log"
	sdklog "go.opentelemetry.io/otel/sdk/log"
)

// InitStdoutLogger configures and initializes a stdoutlog exporter and a LoggerProvider.
func InitStdoutLogger(ctx context.Context, w io.Writer, pretty bool, withoutTimestamps bool) (*sdklog.LoggerProvider, *stdoutlog.Exporter, error) {
	opts := []stdoutlog.Option{
		stdoutlog.WithWriter(w),
	}
	if pretty {
		opts = append(opts, stdoutlog.WithPrettyPrint())
	}
	if withoutTimestamps {
		opts = append(opts, stdoutlog.WithoutTimestamps())
	}

	exporter, err := stdoutlog.New(opts...)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to create stdoutlog exporter: %w", err)
	}

	processor := sdklog.NewSimpleProcessor(exporter)
	provider := sdklog.NewLoggerProvider(
		sdklog.WithProcessor(processor),
	)

	return provider, exporter, nil
}

// EmitLogRecord emits a log record with the specified logger name, message body, and severity.
func EmitLogRecord(ctx context.Context, provider *sdklog.LoggerProvider, loggerName string, msg string, severity log.Severity) {
	logger := provider.Logger(loggerName)
	var record log.Record
	record.SetBody(log.StringValue(msg))
	record.SetSeverity(severity)
	logger.Emit(ctx, record)
}

module sample

go 1.26.6

require (
	go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.19.0
	go.opentelemetry.io/otel/log v0.19.0
	go.opentelemetry.io/otel/sdk/log v0.19.0
)

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/go-logr/logr v1.4.4 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	github.com/google/uuid v1.6.0 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.46.0 // indirect
	go.opentelemetry.io/otel/metric v1.46.0 // indirect
	go.opentelemetry.io/otel/sdk v1.46.0 // indirect
	go.opentelemetry.io/otel/trace v1.46.0 // indirect
	golang.org/x/sys v0.47.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.4 h1:tG4xh9yMsRCAiodLVTxyrkzSZ9+o0L1Kg/+cPVcbP/8=
github.com/go-logr/logr v1.4.4/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
github.com/stretchr/testify v1.12.1 h1:EuwCh5fleGS7H32xRwO3wRGT7DxrDhLAT6FF8MpWDWE=
github.com/stretchr/testify v1.12.1/go.mod h1:MDEgiDPPsNp5cuIrHPPCyornHKgEVbtFUmoNlxoYthg=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.46.0 h1:FHt5/CDyVxi/8IM1CH7VE/rRgq3kLHa2mSTVMO8AWyc=
go.opentelemetry.io/otel v1.46.0/go.mod h1:Gj3SEScelsNC45tp4nSxRYlS+f5iez7W8XPMCt905kE=
go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.19.0 h1:GJkybS+crDMdExT/BUNCEgfrmfboztcS6PhvSo88HKM=
go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.19.0/go.mod h1:NuAyxRYIG2lKX3YQkB+83StTxM7s52PUUkRRiC0wnYI=
go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.22.0 h1:kvMAiLEudKmk+CSG+iYbU8vTUGNNDaf/V09OO5lrTwI=
go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.22.0/go.mod h1:L9Dlksri+MdT1cb2gIiA1cJJYW3Y92ipvDjNxYEyaDI=
go.opentelemetry.io/otel/log v0.19.0 h1:KUZs/GOsw79TBBMfDWsXS+KZ4g2Ckzksd1ymzsIEbo4=
go.opentelemetry.io/otel/log v0.19.0/go.mod h1:5DQYeGmxVIr4n0/BcJvF4upsraHjg6vudJJpnkL6Ipk=
go.opentelemetry.io/otel/log v0.22.0 h1:5DBNnfvaJ6CVdkJ+Jle8Tzs50aSSv49TXGj9XRsEYw0=
go.opentelemetry.io/otel/log v0.22.0/go.mod h1:gzOt/R67vF2GniAqWu8Qv0SXy89f71muHcrkz76PCdc=
go.opentelemetry.io/otel/metric v1.46.0 h1:yBnkXvgV7AXFILZc5K6IZe/CBFF3OS7BJ8ov6/lj0K8=
go.opentelemetry.io/otel/metric v1.46.0/go.mod h1:iPmdWqifKUdzziPkvvzIJXITl56fQx2mGM/DHLB3/2o=
go.opentelemetry.io/otel/sdk v1.46.0 h1:h5CNQQjEbuQXY/JfZtgt3i7HVFV3aHPO2OAwO2eTYPI=
go.opentelemetry.io/otel/sdk v1.46.0/go.mod h1:GAERFXFt5SYCEB+YiKUbMBeza6UaDH7GmGOZEfh2gSM=
go.opentelemetry.io/otel/sdk/log v0.19.0 h1:scYVLqT22D2gqXItnWiocLUKGH9yvkkeql5dBDiXyko=
go.opentelemetry.io/otel/sdk/log v0.19.0/go.mod h1:vFBowwXGLlW9AvpuF7bMgnNI95LiW10szrOdvzBHlAg=
go.opentelemetry.io/otel/sdk/log v0.22.0 h1:PRL+s6P63XT4E/bheEflopPUpVxuvANqZwtt89yhoGk=
go.opentelemetry.io/otel/sdk/log v0.22.0/go.mod h1:JNp0sBELrjCTcu5W3GzABVypeU6vDJjBS+X0JISuz+g=
go.opentelemetry.io/otel/sdk/log/logtest v0.19.0 h1:BEbF7ZBB6qQloV/Ub1+3NQoOUnVtcGkU3XX4Ws3GQfk=
go.opentelemetry.io/otel/sdk/log/logtest v0.22.0 h1:infPnfNrhCNgOUZRs3gWUg8vhoBUHihq02gwK05gzlg=
go.opentelemetry.io/otel/sdk/log/logtest v0.22.0/go.mod h1:gkQZA3z15Bv3KU9vigBTi8dFechSozRP7v94X4VZv+s=
go.opentelemetry.io/otel/sdk/metric v1.46.0 h1:0piZ26EG4RBfebb2jhDH6ERCYHoVWduc3kLgPCwSnSE=
go.opentelemetry.io/otel/sdk/metric v1.46.0/go.mod h1:I1PbKrdVc8Qu8HYVDNtqVIwLwjNrhsV/uFuxfwg8mO4=
go.opentelemetry.io/otel/trace v1.46.0 h1:OULy7ccdJnZtJ0UDYFOIGaCmiWzJ8Vi2G/Rsu60qs1c=
go.opentelemetry.io/otel/trace v1.46.0/go.mod h1:J7GAXweO77XSFkB/rmAqk9D6ihszhFjLU+d9WuUxDLI=
go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/exporters/stdout/stdoutlog@v0.19.0"
  ]
}

package main

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"strings"
	"time"

	"sample"

	"go.opentelemetry.io/otel/log"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	var buf bytes.Buffer

	// 1. Verify exporter initialization with stdoutlog.New, WithWriter, WithPrettyPrint, and WithoutTimestamps
	provider, exporter, err := sample.InitStdoutLogger(ctx, &buf, true, true)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to create exporter: %v\n", err)
		os.Exit(1)
	}
	if exporter == nil {
		fmt.Fprintf(os.Stderr, "Contract failure: exporter is nil\n")
		os.Exit(1)
	}
	if provider == nil {
		fmt.Fprintf(os.Stderr, "Contract failure: provider is nil\n")
		os.Exit(1)
	}

	// 2. Verify log emission through LoggerProvider to stdoutlog exporter
	testMsg := "test log message for verification"
	sample.EmitLogRecord(ctx, provider, "test-logger", testMsg, log.SeverityInfo)

	// Flush and shutdown the provider
	if err := provider.Shutdown(ctx); err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to shutdown logger provider: %v\n", err)
		os.Exit(1)
	}

	output := buf.String()
	if !strings.Contains(output, testMsg) {
		fmt.Fprintf(os.Stderr, "Contract failure: expected output to contain %q, got %q\n", testMsg, output)
		os.Exit(1)
	}

	// 3. Verify clean shutdown on exporter
	if err := exporter.Shutdown(ctx); err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to shutdown exporter: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed successfully.")
}