split printer package to 3 packages

Split printer package to 3 packages: printer, console and logadapter

`printer` package is not very obvious to newcomers. If someone is searching for console or log adapters he will not realize that printer package does that.

README.md

@@ -10,7 +10,7 @@ Tiny **structured logging** abstraction or facade for various logging libraries,
 
 ## Supported logging libraries (via adapters)
 
-[logrus](adapter/logrusadapter), [zap](adapter/zapadapter), [zerolog](adapter/zerologadapter), [glog](adapter/glogadapter), [log15](adapter/log15adapter) and [standard fmt and log packages](adapter/printer)
+[logrus](adapter/logrusadapter), [zap](adapter/zapadapter), [zerolog](adapter/zerologadapter), [glog](adapter/glogadapter), [log15](adapter/log15adapter), [standard log](adapter/logadapter) and [console](adapter/console)
 
 ## When to use?
 
@@ -71,13 +71,13 @@ package main
 import (
 	"context"
 
-	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/adapter/console"
 	"lib"
 )
 
 // End user decides what library to plug in.
 func main() {
-	adapter := printer.StdoutAdapter() // will use fmt.Println
+	adapter := console.StdoutAdapter() // will print messages to console
 	lib.SetLogAdapter(adapter)
 
 	ctx := context.Background()
@@ -114,14 +114,15 @@ func (l YourLib) Method(ctx context.Context) {
 
 
 // end user code
-adapter := printer.StdoutAdapter()
+adapter := console.StdoutAdapter()
 lib := NewLibrary(adapter)
 ```
 
 ### How to use existing adapters
 
 * [Logrus](adapter/logrusadapter/_example/main.go)
-* [fmt.Println and standard log package](adapter/printer/_example/main.go)
+* [standard log package](adapter/logadapter/_example/main.go)
+* [print logs to console using simplified adapter](adapter/console/_example/main.go)
 * [Zap](adapter/zapadapter/_example/main.go)
 * [Zerolog](adapter/zerologadapter/_example/main.go)
 * [glog](adapter/glogadapter/_example/main.go)

adapter/console/_example/main.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"context"
+	"errors"
+
+	"github.com/elgopher/yala/adapter/console"
+	"github.com/elgopher/yala/logger"
+)
+
+var ErrSome = errors.New("ErrSome")
+
+// This example shows how to use yala with minimal console adapter
+func main() {
+	ctx := context.Background()
+
+	// log to console, stdout
+	log := logger.Local{Adapter: console.StdoutAdapter()}
+
+	log.Debug(ctx, "Hello fmt")
+	log.With(ctx, "field_name", "field_value").Info("Some info")
+	log.With(ctx, "parameter", "some value").Warn("Deprecated configuration parameter. It will be removed.")
+	log.WithError(ctx, ErrSome).Error("Some error")
+}

adapter/console/console.go

@@ -0,0 +1,35 @@
+// (c) 2022 Jacek Olszak
+// This code is licensed under MIT license (see LICENSE for details)
+
+package console
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/logger"
+)
+
+// StdoutAdapter returns a logger.Adapter implementation which prints log messages to stdout.
+func StdoutAdapter() logger.Adapter { // nolint
+	return printer.Adapter{Printer: WriterPrinter{os.Stdout}}
+}
+
+// StderrAdapter returns a logger.Adapter implementation which prints log messages to stderr.
+func StderrAdapter() logger.Adapter { // nolint
+	return printer.Adapter{Printer: WriterPrinter{os.Stderr}}
+}
+
+type WriterPrinter struct {
+	Writer io.Writer
+}
+
+func (p WriterPrinter) Println(args ...interface{}) {
+	if p.Writer == nil {
+		return
+	}
+
+	_, _ = fmt.Fprintln(p.Writer, args...)
+}

adapter/console/console_bench_test.go

@@ -0,0 +1,21 @@
+// (c) 2022 Jacek Olszak
+// This code is licensed under MIT license (see LICENSE for details)
+
+package console_test
+
+import (
+	"testing"
+
+	"github.com/elgopher/yala/adapter/console"
+	"github.com/elgopher/yala/adapter/internal/benchmark"
+	"github.com/elgopher/yala/adapter/printer"
+)
+
+func BenchmarkPrinter(b *testing.B) {
+	adapter := printer.Adapter{
+		Printer: console.WriterPrinter{
+			Writer: benchmark.DiscardWriter{},
+		},
+	}
+	benchmark.Adapter(b, adapter)
+}

adapter/console/console_test.go

@@ -0,0 +1,20 @@
+// (c) 2022 Jacek Olszak
+// This code is licensed under MIT license (see LICENSE for details)
+
+package console_test
+
+import (
+	"testing"
+
+	"github.com/elgopher/yala/adapter/console"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWriterPrinter_Println(t *testing.T) {
+	t.Run("should not panic when Writer is nil", func(t *testing.T) {
+		p := console.WriterPrinter{Writer: nil}
+		assert.NotPanics(t, func() {
+			p.Println("")
+		})
+	})
+}

adapter/logadapter/_example/main.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"os"
+
+	"github.com/elgopher/yala/adapter/logadapter"
+	"github.com/elgopher/yala/logger"
+)
+
+var ErrSome = errors.New("ErrSome")
+
+// This example shows how to use yala with standard `log` package
+func main() {
+	ctx := context.Background()
+
+	// log using standard log package
+	standardLog := log.New(os.Stdout, "", log.LstdFlags)
+	adapter := logadapter.Adapter(standardLog)
+	yalaLogger := logger.Local{Adapter: adapter}
+
+	yalaLogger.Debug(ctx, "Hello standard log")
+	yalaLogger.With(ctx, "f1", "v1").With("f2", "f2").Info("Some info")
+	yalaLogger.With(ctx, "parameter", "some").Warn("Deprecated configuration parameter. It will be removed.")
+	yalaLogger.WithError(ctx, ErrSome).Error("Some error")
+}

adapter/logadapter/logadapter.go

@@ -0,0 +1,12 @@
+package logadapter
+
+import (
+	"log"
+
+	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/logger"
+)
+
+func Adapter(l *log.Logger) logger.Adapter { // nolint
+	return printer.Adapter{Printer: l}
+}

adapter/printer/printer_bench_test.go → adapter/logadapter/logadapter_bench_test.go

@@ -1,16 +1,18 @@
 // (c) 2022 Jacek Olszak
 // This code is licensed under MIT license (see LICENSE for details)
 
-package printer_test
+package logadapter_test
 
 import (
+	"log"
 	"testing"
 
 	"github.com/elgopher/yala/adapter/internal/benchmark"
 	"github.com/elgopher/yala/adapter/printer"
 )
 
 func BenchmarkPrinter(b *testing.B) {
-	adapter := printer.Adapter{Printer: printer.WriterPrinter{Writer: benchmark.DiscardWriter{}}}
+	standardLog := log.New(benchmark.DiscardWriter{}, "", log.LstdFlags)
+	adapter := printer.Adapter{Printer: standardLog}
 	benchmark.Adapter(b, adapter)
 }

adapter/printer/printer.go

@@ -5,9 +5,6 @@ package printer
 
 import (
 	"context"
-	"fmt"
-	"io"
-	"os"
 	"strings"
 
 	"github.com/elgopher/yala/adapter/logfmt"
@@ -28,28 +25,6 @@ type Printer interface {
 	Println(...interface{})
 }
 
-// StderrAdapter returns a logger.Adapter implementation which prints log messages to stderr using `fmt` package.
-func StderrAdapter() Adapter {
-	return Adapter{Printer: WriterPrinter{os.Stderr}}
-}
-
-// StdoutAdapter returns a logger.Adapter implementation which prints log messages to stdout using `fmt` package.
-func StdoutAdapter() Adapter {
-	return Adapter{Printer: WriterPrinter{os.Stdout}}
-}
-
-type WriterPrinter struct {
-	Writer io.Writer
-}
-
-func (p WriterPrinter) Println(args ...interface{}) {
-	if p.Writer == nil {
-		return
-	}
-
-	_, _ = fmt.Fprintln(p.Writer, args...)
-}
-
 func (f Adapter) Log(ctx context.Context, entry logger.Entry) {
 	if f.Printer == nil {
 		return

adapter/printer/printer_test.go

@@ -5,6 +5,8 @@ package printer_test
 
 import (
 	"context"
+	"fmt"
+	"io"
 	"strings"
 	"testing"
 
@@ -65,14 +67,12 @@ func TestAdapter_Log(t *testing.T) {
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			var builder strings.Builder
-			adapter := printer.Adapter{
-				Printer: printer.WriterPrinter{Writer: &builder},
-			}
+			var actual strings.Builder
+			adapter := printer.Adapter{Printer: stringPrinter{&actual}}
 			// when
 			adapter.Log(ctx, test.entry)
 			// then
-			assert.Equal(t, test.expectedMessage, builder.String())
+			assert.Equal(t, test.expectedMessage, actual.String())
 		})
 	}
 
@@ -87,17 +87,17 @@ func TestAdapter_Log(t *testing.T) {
 	})
 }
 
-func TestWriterPrinter_Println(t *testing.T) {
-	t.Run("should not panic when Writer is nil", func(t *testing.T) {
-		p := printer.WriterPrinter{Writer: nil}
-		assert.NotPanics(t, func() {
-			p.Println("")
-		})
-	})
-}
-
 type stringError string
 
 func (e stringError) Error() string {
 	return string(e)
 }
+
+type stringPrinter struct {
+	io.StringWriter
+}
+
+func (p stringPrinter) Println(i ...interface{}) {
+	s := fmt.Sprintln(i...)
+	_, _ = p.WriteString(s)
+}

logger/_examples/filter/main.go

@@ -4,13 +4,13 @@ import (
 	"context"
 	"strings"
 
-	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/adapter/console"
 	"github.com/elgopher/yala/logger"
 )
 
 // This advanced example shows how to filter out messages starting with given prefix
 func main() {
-	adapter := printer.StdoutAdapter()
+	adapter := console.StdoutAdapter()
 
 	// creates an adapter which filters out messages
 	filterAdapter := FilterOutMessages{

logger/_examples/reuse/main.go

@@ -3,15 +3,15 @@ package main
 import (
 	"context"
 
-	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/adapter/console"
 	"github.com/elgopher/yala/logger"
 )
 
 // This example shows how to reuse loggers
 func main() {
 	ctx := context.Background()
 
-	log := logger.Local{Adapter: printer.StdoutAdapter()}
+	log := logger.Local{Adapter: console.StdoutAdapter()}
 
 	// requestLogger will log all messages with at least two fields: request_id and user
 	requestLogger := log.With(ctx, "request_id", "123").With("user", "elgopher")

logger/_examples/tags/main.go

@@ -3,15 +3,15 @@ package main
 import (
 	"context"
 
-	"github.com/elgopher/yala/adapter/printer"
+	"github.com/elgopher/yala/adapter/console"
 	"github.com/elgopher/yala/logger"
 )
 
 const tag = "tag"
 
 // This advanced example shows how to log messages with additional field taken from context.Context
 func main() {
-	adapter := printer.StdoutAdapter()
+	adapter := console.StdoutAdapter()
 
 	// creates an adapter which adds field from context to each logged message.
 	addFieldAdapter := AddFieldFromContextAdapter{NextAdapter: adapter}