Add SlogLoggerAdapter

go.mod

@@ -1,6 +1,6 @@
 module github.com/ThreeDotsLabs/watermill
 
-go 1.20
+go 1.21.0
 
 require (
 	github.com/cenkalti/backoff/v3 v3.2.2

go.sum

@@ -19,6 +19,7 @@ github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw
 github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
@@ -54,12 +55,13 @@ github.com/prometheus/procfs v0.9.0 h1:wzCHvIvM5SxWqYvwgVL7yJY8Lz3PKn49KQtpgMYJf
 github.com/prometheus/procfs v0.9.0/go.mod h1:+pB4zwohETzFnmlpe6yd2lSc+0/46IYZRB/chUwxUZY=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
-github.com/sony/gobreaker v0.5.0 h1:dRCvqm0P490vZPmy7ppEk2qCnCieBooFJ+YoXGYB+yg=
-github.com/sony/gobreaker v0.5.0/go.mod h1:ZKptC7FHNvhBz7dN2LGjPVBz2sZJmc0/PkyDJOjmxWY=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@@ -96,5 +98,7 @@ google.golang.org/protobuf v1.28.1 h1:d0NfwRgPtno5B1Wa6L2DAG+KivqkdutMf1UhdNx175
 google.golang.org/protobuf v1.28.1/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

slog.go

@@ -0,0 +1,70 @@
+package watermill
+
+import (
+	"log/slog"
+)
+
+// LevelTrace must be added, because [slog] package does not have one by default. Generate it by subtracting 4 levels from [slog.Debug] following the example of [slog.LevelWarn] and [slog.LevelError] which are set to 4 and 8.
+const LevelTrace = slog.LevelDebug - 4
+
+func slogAttrsFromFields(fields LogFields) []any {
+	result := make([]any, 0, len(fields)*2)
+
+	for key, value := range fields {
+		// result = append(result, slog.Any(key, value))
+		result = append(result, key, value)
+	}
+
+	return result
+}
+
+// SlogLoggerAdapter wraps [slog.Logger].
+type SlogLoggerAdapter struct {
+	slog *slog.Logger
+}
+
+// Error logs a message to [slog.LevelError].
+func (s *SlogLoggerAdapter) Error(msg string, err error, fields LogFields) {
+	s.slog.Error(msg, append(slogAttrsFromFields(fields), "error", err)...)
+}
+
+// Info logs a message to [slog.LevelInfo].
+func (s *SlogLoggerAdapter) Info(msg string, fields LogFields) {
+	s.slog.Info(msg, slogAttrsFromFields(fields)...)
+}
+
+// Debug logs a message to [slog.LevelDebug].
+func (s *SlogLoggerAdapter) Debug(msg string, fields LogFields) {
+	s.slog.Debug(msg, slogAttrsFromFields(fields)...)
+}
+
+// Trace logs a message to [LevelTrace].
+func (s *SlogLoggerAdapter) Trace(msg string, fields LogFields) {
+	s.slog.Log(
+		// Void context, following the slog example
+		// as it treats context slighly differently from
+		// normal usage, minding contextual
+		// values, but ignoring contextual deadline.
+		// See the [slog] package documentation
+		// for more details.
+		nil,
+		LevelTrace,
+		msg,
+		slogAttrsFromFields(fields)...,
+	)
+}
+
+// With return a [SlogLoggerAdapter] with a set of fields injected into all consequent logging messages.
+func (s *SlogLoggerAdapter) With(fields LogFields) LoggerAdapter {
+	return &SlogLoggerAdapter{slog: s.slog.With(slogAttrsFromFields(fields)...)}
+}
+
+// NewSlogLogger creates an adapter to the standard library's structured logging package. A `nil` logger is substituted for the result of [slog.Default].
+func NewSlogLogger(logger *slog.Logger) LoggerAdapter {
+	if logger == nil {
+		logger = slog.Default()
+	}
+	return &SlogLoggerAdapter{
+		slog: logger,
+	}
+}

slog_test.go

@@ -0,0 +1,53 @@
+package watermill
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+	"testing"
+
+	"log/slog"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSlogLoggerAdapter(t *testing.T) {
+	b := &bytes.Buffer{}
+
+	logger := NewSlogLogger(slog.New(slog.NewTextHandler(
+		b, // output
+		&slog.HandlerOptions{
+			Level: LevelTrace,
+			ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+				if a.Key == "time" && len(groups) == 0 {
+					// omit time stamp to make the test idempotent
+					a.Value = slog.StringValue("[omit]")
+				}
+				return a
+			},
+		},
+	)))
+
+	logger = logger.With(LogFields{
+		"common1": "commonvalue",
+	})
+	logger.Trace("test trace", LogFields{
+		"field1": "value1",
+	})
+	logger.Error("test error", errors.New("error message"), LogFields{
+		"field2": "value2",
+	})
+	logger.Info("test info", LogFields{
+		"field3": "value3",
+	})
+
+	assert.Equal(t,
+		strings.TrimSpace(b.String()),
+		strings.TrimSpace(`
+time=[omit] level=DEBUG-4 msg="test trace" common1=commonvalue field1=value1
+time=[omit] level=ERROR msg="test error" common1=commonvalue field2=value2 error="error message"
+time=[omit] level=INFO msg="test info" common1=commonvalue field3=value3
+      `),
+		"Logging output does not match saved template.",
+	)
+}