Move zap adapter to a separate module, add slog adapter

.github/workflows/go.yml

@@ -41,10 +41,18 @@ jobs:
         go vet ./...
         go build -o /dev/null ./...
 
+    - name: Test zap logger module
+      if: matrix.go-version == 'stable'
+      working-directory: logger/zaplogger
+      run: |
+        go vet ./...
+        go test -v -race -coverprofile=../../coverage-zaplogger.txt -covermode=atomic ./...
+
     - uses: codecov/codecov-action@v4
       if: matrix.go-version == 'stable'
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
+        files: ./coverage.txt,./coverage-zaplogger.txt
 
   # end-to-end tests with the real external systems in Docker, see e2e/README.md
   e2e:

Readme.md

@@ -18,6 +18,9 @@ tinyconf fills config structs with values from drivers. When initializing `tinyc
 as well as drivers. Drivers are applied in the order of addition, the next driver overrides values of the previous one,
 so the last driver has the highest priority. You can also add your own driver.
 
+Loggers: `logger.NewFmtLogger`, `logger.NewSlogLogger` (Go 1.21+), and the adapter of zap in the separate module
+`github.com/insei/tinyconf/logger/zaplogger`, so zap is not a dependency of the core.
+
 `tinyconf.Manager` has methods:
 
 | Method | Description |

docs/features/logging.md

@@ -69,10 +69,26 @@ import "github.com/insei/tinyconf/logger"
 // prints to stdout, levels: FATAL, ERROR, WARN, INFO, DEBUG, TRACE
 tinyconf.WithLogger(logger.NewFmtLogger(logger.INFO))
 
+// wraps *slog.Logger, Go 1.21 or newer
+tinyconf.WithLogger(logger.NewSlogLogger(slog.Default()))
+```
+
+The adapter of [zap](https://github.com/uber-go/zap) is a separate module, so zap is not a dependency of tinyconf for the applications with other loggers:
+
+```bash
+go get github.com/insei/tinyconf/logger/zaplogger
+```
+
+```go
+import "github.com/insei/tinyconf/logger/zaplogger"
+
 // wraps *zap.Logger
-tinyconf.WithLogger(logger.NewZapLogger(zapLogger))
+tinyconf.WithLogger(zaplogger.New(zapLogger))
 ```
 
+!!! note "Migration"
+    `logger.NewZapLogger(l)` of the previous versions is `zaplogger.New(l)` from the `github.com/insei/tinyconf/logger/zaplogger` module.
+
 ## Custom logger
 
 Implement the `tinyconf.Logger` interface:

e2e/go.sum

@@ -180,10 +180,12 @@ go.opentelemetry.io/otel/sdk/metric v1.44.0 h1:3LlKgI+VjbVsjNRFZJZAJ30WjXC5VkNRk
 go.opentelemetry.io/otel/sdk/metric v1.44.0/go.mod h1:5B5pMARnXxKhltooO4xUuCBorl65a4EpnTalObqOigA=
 go.opentelemetry.io/otel/trace v1.44.0 h1:jxF5CsGYCe74MCRx2X4g7WsY/VBKRqqpNvXlX/6gtIk=
 go.opentelemetry.io/otel/trace v1.44.0/go.mod h1:oLl1jrMQAVo6v3GAggN+1VH9VIz9iUSvW53sW1Q8PIE=
-go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
-go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
-go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
+go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
+go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
+go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
+go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
+go.uber.org/zap v1.17.0 h1:MTjgFu6ZLKvY6Pvaqk97GlxNBuMpV4Hy/3P6tRGlI2U=
+go.uber.org/zap v1.17.0/go.mod h1:MXVU+bhUf/A7Xi2HNOnopQOrmycQ5Ih87HtOu4q5SSo=
 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/crypto v0.54.0 h1:YLIA59K4fiNzHzjnZt2tUJQjQtUWfWbeHBqKtk3eScw=

example/go.mod

@@ -9,8 +9,6 @@ require (
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/insei/cast v1.1.1 // indirect
 	github.com/insei/fmap/v3 v3.3.0 // indirect
-	go.uber.org/multierr v1.10.0 // indirect
-	go.uber.org/zap v1.27.0 // indirect
 	golang.org/x/sys v0.13.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

example/go.sum

@@ -12,12 +12,6 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 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.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
-go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
-go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
-go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
-go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
 golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

go.mod

@@ -8,14 +8,12 @@ require (
 	github.com/insei/cast v1.1.1
 	github.com/insei/fmap/v3 v3.3.0
 	github.com/stretchr/testify v1.9.0
-	go.uber.org/zap v1.27.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	go.uber.org/multierr v1.10.0 // indirect
 	golang.org/x/sys v0.13.0 // indirect
 )

go.sum

@@ -14,11 +14,6 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 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.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
-go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
-go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
-go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
 golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

logger/fields_test.go

@@ -4,10 +4,6 @@ import (
 	"strings"
 	"testing"
 
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
-	"go.uber.org/zap/zaptest/observer"
-
 	"github.com/insei/tinyconf"
 )
 
@@ -22,18 +18,3 @@ func TestFmtLogger_Fields(t *testing.T) {
 		}
 	}
 }
-
-func TestZapLogger_With(t *testing.T) {
-	core, logs := observer.New(zapcore.DebugLevel)
-	logger := NewZapLogger(zap.New(core)).With(tinyconf.Field{Key: "driver", Value: "env"})
-	logger.Info("message", tinyconf.Field{Key: "field", Value: "Name"})
-
-	entries := logs.All()
-	if len(entries) != 1 {
-		t.Fatalf("Expected 1 log entry, but got %d", len(entries))
-	}
-	fields := entries[0].ContextMap()
-	if entries[0].Message != "message" || fields["driver"] != "env" || fields["field"] != "Name" {
-		t.Errorf("Unexpected log entry: %s %v", entries[0].Message, fields)
-	}
-}

logger/slog.go

@@ -0,0 +1,56 @@
+//go:build go1.21
+
+package logger
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/insei/tinyconf"
+)
+
+type slogLogger struct {
+	l *slog.Logger
+}
+
+func attrs(fields []tinyconf.Field) []any {
+	args := make([]any, 0, len(fields))
+	for _, field := range fields {
+		args = append(args, slog.Any(field.Key, field.Value))
+	}
+	return args
+}
+
+func (s *slogLogger) log(level slog.Level, msg string, fields []tinyconf.Field) {
+	s.l.Log(context.Background(), level, msg, attrs(fields)...)
+}
+
+// Debug logs a message at the DEBUG level.
+func (s *slogLogger) Debug(msg string, fields ...tinyconf.Field) {
+	s.log(slog.LevelDebug, msg, fields)
+}
+
+// Error logs a message at the ERROR level.
+func (s *slogLogger) Error(msg string, fields ...tinyconf.Field) {
+	s.log(slog.LevelError, msg, fields)
+}
+
+// Warn logs a message at the WARN level.
+func (s *slogLogger) Warn(msg string, fields ...tinyconf.Field) {
+	s.log(slog.LevelWarn, msg, fields)
+}
+
+// Info logs a message at the INFO level.
+func (s *slogLogger) Info(msg string, fields ...tinyconf.Field) {
+	s.log(slog.LevelInfo, msg, fields)
+}
+
+// With returns the logger with the fields.
+func (s *slogLogger) With(fields ...tinyconf.Field) tinyconf.Logger {
+	return &slogLogger{l: s.l.With(attrs(fields)...)}
+}
+
+// NewSlogLogger returns the logger of tinyconf that writes to the slog logger, it needs Go 1.21 or newer.
+func NewSlogLogger(l *slog.Logger) tinyconf.Logger {
+	return &slogLogger{l: l}
+}

logger/slog_test.go

@@ -0,0 +1,37 @@
+//go:build go1.21
+
+package logger
+
+import (
+	"bytes"
+	"log/slog"
+	"testing"
+
+	"github.com/insei/tinyconf"
+)
+
+func TestSlogLogger(t *testing.T) {
+	var out bytes.Buffer
+	handler := slog.NewTextHandler(&out, &slog.HandlerOptions{
+		Level: slog.LevelDebug,
+		// the time is removed for the stable output
+		ReplaceAttr: func(_ []string, a slog.Attr) slog.Attr {
+			if a.Key == slog.TimeKey {
+				return slog.Attr{}
+			}
+			return a
+		},
+	})
+	logger := NewSlogLogger(slog.New(handler)).With(tinyconf.Field{Key: "driver", Value: "env"})
+	logger.Debug("debug", tinyconf.Field{Key: "field", Value: "Name"})
+	logger.Info("info")
+	logger.Warn("warn")
+	logger.Error("error", tinyconf.Field{Key: "details", Value: "failed"})
+	want := "level=DEBUG msg=debug driver=env field=Name\n" +
+		"level=INFO msg=info driver=env\n" +
+		"level=WARN msg=warn driver=env\n" +
+		"level=ERROR msg=error driver=env details=failed\n"
+	if out.String() != want {
+		t.Errorf("unexpected output:\n%s\nwant:\n%s", out.String(), want)
+	}
+}