Add skeleton for zerolog bridge (#5782)

This PR introduces the `otelzerolog` package, which provides a
`SeverityHook` to bridge the logging capabilities of Zerolog with
OpenTelemetry. The following key features are included:

## Changes

- Added `config` struct to handle configuration options.
- Implemented `Option` interface and related functions (`WithVersion`,
`WithSchemaURL`, `WithLoggerProvider`).
- Created `NewSeverityHook` function to initialize a `SeverityHook`.
- Defined `SeverityHook` struct to perform the logging bridge
functionality.

Part of
#5405

---------

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

bridges/otelzerolog/example_test.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package otelzerolog_test
+
+import (
+	"os"
+
+	"github.com/rs/zerolog"
+
+	"go.opentelemetry.io/contrib/bridges/otelzerolog"
+	"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 a logger that emits logs to both STDOUT and the OTel Go SDK.
+	hook := otelzerolog.NewHook("my/pkg/name", otelzerolog.WithLoggerProvider(provider))
+	logger := zerolog.New(os.Stdout).With().Logger()
+	logger = logger.Hook(hook)
+}

bridges/otelzerolog/go.mod

@@ -0,0 +1,23 @@
+module go.opentelemetry.io/contrib/bridges/otelzerolog
+
+go 1.21
+
+require (
+	github.com/rs/zerolog v1.33.0
+	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/otel/log v0.3.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.4.1 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/otel v1.27.0 // indirect
+	go.opentelemetry.io/otel/metric v1.27.0 // indirect
+	go.opentelemetry.io/otel/trace v1.27.0 // indirect
+	golang.org/x/sys v0.12.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

bridges/otelzerolog/go.sum

@@ -0,0 +1,40 @@
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+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 v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
+github.com/go-logr/logr v1.4.1/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/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+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/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+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/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+github.com/rs/zerolog v1.33.0 h1:1cU2KZkvPxNyfgEmhHAz/1A9Bz+llsdYzklWFzgp0r8=
+github.com/rs/zerolog v1.33.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
+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 v1.27.0 h1:9BZoF3yMK/O1AafMiQTVu0YDj5Ea4hPhxCs7sGva+cg=
+go.opentelemetry.io/otel v1.27.0/go.mod h1:DMpAK8fzYRzs+bi3rS5REupisuqTheUlSZJ1WnZaPAQ=
+go.opentelemetry.io/otel/log v0.3.0 h1:kJRFkpUFYtny37NQzL386WbznUByZx186DpEMKhEGZs=
+go.opentelemetry.io/otel/log v0.3.0/go.mod h1:ziCwqZr9soYDwGNbIL+6kAvQC+ANvjgG367HVcyR/ys=
+go.opentelemetry.io/otel/metric v1.27.0 h1:hvj3vdEKyeCi4YaYfNjv2NUje8FqKqUY8IlF0FxV/ik=
+go.opentelemetry.io/otel/metric v1.27.0/go.mod h1:mVFgmRlhljgBiuk/MP/oKylr4hs85GZAylncepAX/ak=
+go.opentelemetry.io/otel/trace v1.27.0 h1:IqYb813p7cmbHk0a5y6pD5JPakbVfftRXABGt5/Rscw=
+go.opentelemetry.io/otel/trace v1.27.0/go.mod h1:6RiD1hkAprV4/q+yd2ln1HG9GoPx39SuvvstaLBl+l4=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+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/otelzerolog/hook.go

@@ -0,0 +1,104 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package otelzerolog provides a [Hook], a [zerolog.Hook] implementation that
+// can be used to bridge between the [zerolog] API and [OpenTelemetry].
+// [OpenTelemetry]: https://opentelemetry.io/docs/concepts/signals/logs/
+package otelzerolog // import "go.opentelemetry.io/contrib/bridges/otelzerolog"
+
+import (
+	"github.com/rs/zerolog"
+
+	"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 Hook.
+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 [Hook].
+//
+// By default if this Option is not provided, the Hook will use the global
+// LoggerProvider.
+func WithLoggerProvider(provider log.LoggerProvider) Option {
+	return optFunc(func(c config) config {
+		c.provider = provider
+		return c
+	})
+}
+
+// Hook is a [zerolog.Hook] that sends all logging records it receives to
+// OpenTelemetry. See package documentation for how conversions are made.
+type Hook struct {
+	logger log.Logger
+}
+
+// NewHook returns a new [Hook] to be used as a [Zerolog.Hook].
+// If [WithLoggerProvider] is not provided, the returned Hook will use the
+// global LoggerProvider.
+func NewHook(name string, options ...Option) *Hook {
+	cfg := newConfig(options)
+	return &Hook{
+		logger: cfg.logger(name),
+	}
+}
+
+// Run handles the passed record, and sends it to OpenTelemetry.
+func (h Hook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+	// TODO
+}

bridges/otelzerolog/hook_test.go

@@ -0,0 +1,105 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+package otelzerolog
+
+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 version",
+			options: []Option{
+				WithVersion("1.0"),
+			},
+			wantConfig: config{
+				version:  "1.0",
+				provider: global.GetLoggerProvider(),
+			},
+		},
+		{
+			name: "with a custom schema URL",
+			options: []Option{
+				WithSchemaURL("https://example.com"),
+			},
+			wantConfig: config{
+				schemaURL: "https://example.com",
+				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 TestNewHook(t *testing.T) {
+	const name = "test_hook"
+	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 := NewHook(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/otelzerolog
   - go.opentelemetry.io/contrib/bridges/otelzap
   - go.opentelemetry.io/contrib/instrgen
   - go.opentelemetry.io/contrib/instrgen/driver