Add config and doc for stdoutlog exporter (#5158)

.github/dependabot.yml

@@ -190,6 +190,15 @@ updates:
     schedule:
       interval: weekly
       day: sunday
+  - package-ecosystem: gomod
+    directory: /exporters/stdout/stdoutlog
+    labels:
+      - dependencies
+      - go
+      - Skip Changelog
+    schedule:
+      interval: weekly
+      day: sunday
   - package-ecosystem: gomod
     directory: /exporters/stdout/stdoutmetric
     labels:

exporters/stdout/stdoutlog/README.md

@@ -0,0 +1,3 @@
+# STDOUT Log Exporter
+
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel/exporters/stdout/stdoutlog)](https://pkg.go.dev/go.opentelemetry.io/otel/exporters/stdout/stdoutlog)

exporters/stdout/stdoutlog/config.go

@@ -0,0 +1,85 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package stdoutlog // import "go.opentelemetry.io/otel/exporters/stdout/stdoutlog"
+
+import (
+	"io"
+	"os"
+)
+
+var (
+	defaultWriter      = os.Stdout
+	defaultPrettyPrint = false
+	defaultTimestamps  = true
+)
+
+// config contains options for the STDOUT exporter.
+type config struct {
+	// Writer is the destination.  If not set, os.Stdout is used.
+	Writer io.Writer
+
+	// PrettyPrint will encode the output into readable JSON. Default is
+	// false.
+	PrettyPrint bool
+
+	// Timestamps specifies if timestamps should be printed. Default is
+	// true.
+	Timestamps bool
+}
+
+// newConfig creates a validated Config configured with options.
+func newConfig(options []Option) config {
+	cfg := config{
+		Writer:      defaultWriter,
+		PrettyPrint: defaultPrettyPrint,
+		Timestamps:  defaultTimestamps,
+	}
+	for _, opt := range options {
+		cfg = opt.apply(cfg)
+	}
+	return cfg
+}
+
+// Option sets the configuration value for an Exporter.
+type Option interface {
+	apply(config) config
+}
+
+// WithWriter sets the export stream destination.
+func WithWriter(w io.Writer) Option {
+	return writerOption{w}
+}
+
+type writerOption struct {
+	W io.Writer
+}
+
+func (o writerOption) apply(cfg config) config {
+	cfg.Writer = o.W
+	return cfg
+}
+
+// WithPrettyPrint prettifies the emitted output.
+func WithPrettyPrint() Option {
+	return prettyPrintOption(true)
+}
+
+type prettyPrintOption bool
+
+func (o prettyPrintOption) apply(cfg config) config {
+	cfg.PrettyPrint = bool(o)
+	return cfg
+}
+
+// WithoutTimestamps sets the export stream to not include timestamps.
+func WithoutTimestamps() Option {
+	return timestampsOption(false)
+}
+
+type timestampsOption bool
+
+func (o timestampsOption) apply(cfg config) config {
+	cfg.Timestamps = bool(o)
+	return cfg
+}

exporters/stdout/stdoutlog/config_test.go

@@ -0,0 +1,62 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package stdoutlog // import "go.opentelemetry.io/otel/exporters/stdout/stdoutlog"
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewConfig(t *testing.T) {
+	testCases := []struct {
+		name     string
+		options  []Option
+		expected config
+	}{
+		{
+			name: "default",
+			expected: config{
+				Writer:      os.Stdout,
+				PrettyPrint: false,
+				Timestamps:  true,
+			},
+		},
+		{
+			name:    "WithWriter",
+			options: []Option{WithWriter(os.Stderr)},
+			expected: config{
+				Writer:      os.Stderr,
+				PrettyPrint: false,
+				Timestamps:  true,
+			},
+		},
+		{
+			name:    "WithPrettyPrint",
+			options: []Option{WithPrettyPrint()},
+			expected: config{
+				Writer:      os.Stdout,
+				PrettyPrint: true,
+				Timestamps:  true,
+			},
+		},
+		{
+			name:    "WithoutTimestamps",
+			options: []Option{WithoutTimestamps()},
+			expected: config{
+				Writer:      os.Stdout,
+				PrettyPrint: false,
+				Timestamps:  false,
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := newConfig(tc.options)
+			assert.Equal(t, tc.expected, cfg)
+		})
+	}
+}

exporters/stdout/stdoutlog/doc.go

@@ -0,0 +1,12 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package stdoutlog provides an exporter for OpenTelemetry log
+// telemetry.
+//
+// The exporter is intended to be used for testing and debugging, it is not
+// meant for production use. Additionally, it does not provide an interchange
+// format for OpenTelemetry that is supported with any stability or
+// compatibility guarantees. If these are needed features, please use the OTLP
+// exporter instead.
+package stdoutlog // import "go.opentelemetry.io/otel/exporters/stdout/stdoutlog"

exporters/stdout/stdoutlog/go.mod

@@ -0,0 +1,11 @@
+module go.opentelemetry.io/otel/exporters/stdout/stdoutlog
+
+go 1.21
+
+require github.com/stretchr/testify v1.9.0
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

exporters/stdout/stdoutlog/go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

versions.yaml

@@ -45,3 +45,4 @@ excluded-modules:
   - go.opentelemetry.io/otel/internal/tools
   - go.opentelemetry.io/otel/sdk/log
   - go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp
+  - go.opentelemetry.io/otel/exporters/stdout/stdoutlog