Add skeleton for otellogr bridge (#6097)

This PR is the skeleton for otellogr package, which provides a LogSink
to bridge the logging capabilities for Logr with OpenTelemetry

Part of #5192

---------

Co-authored-by: Robert Pająk <[email protected]>

CODEOWNERS

@@ -29,6 +29,7 @@ bridges/otelslog                                                        @open-te
 bridges/otellogrus/                                                     @open-telemetry/go-approvers @dmathieu @pellared
 bridges/prometheus/                                                     @open-telemetry/go-approvers @dashpole
 bridges/otelzap/                                                        @open-telemetry/go-approvers @pellared @khushijain21
+bridges/otellogr/                                                       @open-telemetry/go-approvers @scorpionknifes @pellared
 
 config/                                                                 @open-telemetry/go-approvers @MadVikingGod @pellared @codeboten
 

bridges/otellogr/example_test.go

@@ -0,0 +1,22 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package otellogr_test
+
+import (
+	"github.com/go-logr/logr"
+
+	"go.opentelemetry.io/contrib/bridges/otellogr"
+	"go.opentelemetry.io/otel/log/noop"
+)
+
+func Example() {
+	// Use a working LoggerProvider implementation instead e.g. using go.opentelemetry.io/otel/sdk/log.
+	provider := noop.NewLoggerProvider()
+
+	// Create an logr.Logger with *otellogr.LogSink and use it in your application.
+	logr.New(otellogr.NewLogSink(
+		"my/pkg/name",
+		otellogr.WithLoggerProvider(provider)),
+	)
+}

bridges/otellogr/go.mod

@@ -0,0 +1,19 @@
+module go.opentelemetry.io/contrib/bridges/otellogr
+
+go 1.22
+
+require (
+	github.com/go-logr/logr v1.4.2
+	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/otel/log v0.5.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/otel v1.29.0 // indirect
+	go.opentelemetry.io/otel/metric v1.29.0 // indirect
+	go.opentelemetry.io/otel/trace v1.29.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

bridges/otellogr/go.sum

@@ -0,0 +1,25 @@
+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/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
+github.com/go-logr/logr v1.4.2/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 v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+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=
+go.opentelemetry.io/otel v1.29.0 h1:PdomN/Al4q/lN6iBJEN3AwPvUiHPMlt93c8bqTG5Llw=
+go.opentelemetry.io/otel v1.29.0/go.mod h1:N/WtXPs1CNCUEx+Agz5uouwCba+i+bJGFicT8SR4NP8=
+go.opentelemetry.io/otel/log v0.5.0 h1:x1Pr6Y3gnXgl1iFBwtGy1W/mnzENoK0w0ZoaeOI3i30=
+go.opentelemetry.io/otel/log v0.5.0/go.mod h1:NU/ozXeGuOR5/mjCRXYbTC00NFJ3NYuraV/7O78F0rE=
+go.opentelemetry.io/otel/metric v1.29.0 h1:vPf/HFWTNkPu1aYeIsc98l4ktOQaL6LeSoeV2g+8YLc=
+go.opentelemetry.io/otel/metric v1.29.0/go.mod h1:auu/QWieFVWx+DmQOUMgj0F8LHWdgalxXqvp7BII/W8=
+go.opentelemetry.io/otel/trace v1.29.0 h1:J/8ZNK4XgR7a21DZUAsbF8pZ5Jcw1VhACmnYt39JTi4=
+go.opentelemetry.io/otel/trace v1.29.0/go.mod h1:eHl3w0sp3paPkYstJOmAimxhiFXPg+MMTlEh3nsQgWQ=
+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=

bridges/otellogr/logsink.go

@@ -0,0 +1,146 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package otellogr provides a [LogSink], a [logr.LogSink] implementation that
+// can be used to bridge between the [logr] API and [OpenTelemetry].
+//
+// [OpenTelemetry]: https://opentelemetry.io/docs/concepts/signals/logs/
+package otellogr // import "go.opentelemetry.io/contrib/bridges/otellogr"
+
+import (
+	"github.com/go-logr/logr"
+
+	"go.opentelemetry.io/otel/log"
+	"go.opentelemetry.io/otel/log/global"
+)
+
+type config struct {
+	provider  log.LoggerProvider
+	version   string
+	schemaURL string
+}
+
+func newConfig(options []Option) config {
+	var c config
+	for _, opt := range options {
+		c = opt.apply(c)
+	}
+
+	if c.provider == nil {
+		c.provider = global.GetLoggerProvider()
+	}
+
+	return c
+}
+
+func (c config) logger(name string) log.Logger {
+	var opts []log.LoggerOption
+	if c.version != "" {
+		opts = append(opts, log.WithInstrumentationVersion(c.version))
+	}
+	if c.schemaURL != "" {
+		opts = append(opts, log.WithSchemaURL(c.schemaURL))
+	}
+	return c.provider.Logger(name, opts...)
+}
+
+// Option configures a [LogSink].
+type Option interface {
+	apply(config) config
+}
+
+type optFunc func(config) config
+
+func (f optFunc) apply(c config) config { return f(c) }
+
+// WithVersion returns an [Option] that configures the version of the
+// [log.Logger] used by a [Hook]. The version should be the version of the
+// package that is being logged.
+func WithVersion(version string) Option {
+	return optFunc(func(c config) config {
+		c.version = version
+		return c
+	})
+}
+
+// WithSchemaURL returns an [Option] that configures the semantic convention
+// schema URL of the [log.Logger] used by a [Hook]. The schemaURL should be
+// the schema URL for the semantic conventions used in log records.
+func WithSchemaURL(schemaURL string) Option {
+	return optFunc(func(c config) config {
+		c.schemaURL = schemaURL
+		return c
+	})
+}
+
+// WithLoggerProvider returns an [Option] that configures [log.LoggerProvider]
+// used by a [LogSink] to create its [log.Logger].
+//
+// By default if this Option is not provided, the LogSink will use the global
+// LoggerProvider.
+func WithLoggerProvider(provider log.LoggerProvider) Option {
+	return optFunc(func(c config) config {
+		c.provider = provider
+		return c
+	})
+}
+
+// NewLogSink returns a new [LogSink] to be used as a [logr.LogSink].
+//
+// If [WithLoggerProvider] is not provided, the returned LogSink will use the
+// global LoggerProvider.
+func NewLogSink(name string, options ...Option) *LogSink {
+	c := newConfig(options)
+	return &LogSink{
+		name:   name,
+		logger: c.logger(name),
+	}
+}
+
+// LogSink is a [logr.LogSink] that sends all logging records it receives to
+// OpenTelemetry. See package documentation for how conversions are made.
+type LogSink struct {
+	// Ensure forward compatibility by explicitly making this not comparable.
+	noCmp [0]func() //nolint: unused  // This is indeed used.
+
+	name   string
+	logger log.Logger
+}
+
+// Compile-time check *Handler implements logr.LogSink.
+var _ logr.LogSink = (*LogSink)(nil)
+
+// Enabled tests whether this LogSink is enabled at the specified V-level.
+// For example, commandline flags might be used to set the logging
+// verbosity and disable some info logs.
+func (l *LogSink) Enabled(level int) bool {
+	// TODO
+	return true
+}
+
+// Error logs an error, with the given message and key/value pairs.
+func (l *LogSink) Error(err error, msg string, keysAndValues ...any) {
+	// TODO
+}
+
+// Info logs a non-error message with the given key/value pairs.
+func (l *LogSink) Info(level int, msg string, keysAndValues ...any) {
+	// TODO
+}
+
+// Init initializes the LogSink.
+func (l *LogSink) Init(info logr.RuntimeInfo) {
+	// TODO
+}
+
+// WithName returns a new LogSink with the specified name appended.
+func (l LogSink) WithName(name string) logr.LogSink {
+	// TODO
+	return &l
+}
+
+// WithValues returns a new LogSink with additional key/value pairs.
+func (l LogSink) WithValues(keysAndValues ...any) logr.LogSink {
+	// TODO
+	return &l
+}

bridges/otellogr/logsink_test.go

@@ -0,0 +1,98 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+package otellogr
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/otel/log"
+	"go.opentelemetry.io/otel/log/embedded"
+	"go.opentelemetry.io/otel/log/global"
+)
+
+type mockLoggerProvider struct {
+	embedded.LoggerProvider
+}
+
+func (mockLoggerProvider) Logger(name string, options ...log.LoggerOption) log.Logger {
+	return nil
+}
+
+func TestNewConfig(t *testing.T) {
+	customLoggerProvider := mockLoggerProvider{}
+
+	for _, tt := range []struct {
+		name    string
+		options []Option
+
+		wantConfig config
+	}{
+		{
+			name: "with no options",
+
+			wantConfig: config{
+				provider: global.GetLoggerProvider(),
+			},
+		},
+		{
+			name: "with a custom instrumentation scope",
+			options: []Option{
+				WithVersion("42.0"),
+			},
+
+			wantConfig: config{
+				version:  "42.0",
+				provider: global.GetLoggerProvider(),
+			},
+		},
+		{
+			name: "with a custom logger provider",
+			options: []Option{
+				WithLoggerProvider(customLoggerProvider),
+			},
+
+			wantConfig: config{
+				provider: customLoggerProvider,
+			},
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.wantConfig, newConfig(tt.options))
+		})
+	}
+}
+
+func TestNewLogSink(t *testing.T) {
+	const name = "test_logsink"
+	provider := global.GetLoggerProvider()
+
+	for _, tt := range []struct {
+		name       string
+		options    []Option
+		wantLogger log.Logger
+	}{
+		{
+			name:       "with default options",
+			wantLogger: provider.Logger(name),
+		},
+		{
+			name: "with version and schema URL",
+			options: []Option{
+				WithVersion("1.0"),
+				WithSchemaURL("https://example.com"),
+			},
+			wantLogger: provider.Logger(name,
+				log.WithInstrumentationVersion("1.0"),
+				log.WithSchemaURL("https://example.com"),
+			),
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			hook := NewLogSink(name, tt.options...)
+			assert.NotNil(t, hook)
+			assert.Equal(t, tt.wantLogger, hook.logger)
+		})
+	}
+}

versions.yaml

@@ -88,6 +88,7 @@ module-sets:
     modules:
       - go.opentelemetry.io/contrib/detectors/azure/azurevm
 excluded-modules:
+  - go.opentelemetry.io/contrib/bridges/otellogr
   - go.opentelemetry.io/contrib/instrgen
   - go.opentelemetry.io/contrib/instrgen/driver
   - go.opentelemetry.io/contrib/instrgen/testdata/interface