go-aah/aah#66 added logger hooks capability

Author: jeevatkm

console_receiver_test.go

@@ -123,9 +123,9 @@ func testConsoleLogger(t *testing.T, cfgStr string) {
 	logger.Errorf("Yes, yes, yes - %v", "finally an error")
 
 	exit = func(code int) {}
-	logger.Fatal("Yes, yes, yes - finally an error")
-	logger.Fatalf("Yes, yes, yes - %v", "finally an error")
-	logger.Fatalln("Yes, yes, yes - %v", "finally an error")
+	logger.Fatal("Yes, yes, yes - at last fatal")
+	logger.Fatalf("Yes, yes, yes - %v", "at last fatal")
+	logger.Fatalln("Yes, yes, yes - %v", "at last fatal")
 	exit = os.Exit
 
 	assert.NotNil(t, logger.ToGoLogger())

hook.go

@@ -0,0 +1,54 @@
+// Copyright (c) Jeevanandam M (https://github.com/jeevatkm)
+// go-aah/log source code and usage is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package log
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+)
+
+var (
+	// ErrHookFuncIsNil is returned when hook function is nil.
+	ErrHookFuncIsNil = errors.New("log: hook func is nil")
+
+	hooks = make(map[string]HookFunc)
+	mu    = &sync.RWMutex{}
+)
+
+// HookFunc type is aah framework logger custom hook.
+type HookFunc func(e Entry)
+
+//‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
+// Global methods
+//___________________________________
+
+// AddHook method is to add logger hook function.
+func AddHook(name string, hook HookFunc) error {
+	if hook == nil {
+		return ErrHookFuncIsNil
+	}
+
+	mu.Lock()
+	defer mu.Unlock()
+	if _, found := hooks[name]; found {
+		return fmt.Errorf("log: hook name '%v' is already added, skip it", name)
+	}
+
+	hooks[name] = hook
+	return nil
+}
+
+//‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
+// Unexported methods
+//___________________________________
+
+func executeHooks(e Entry) {
+	mu.RLock()
+	defer mu.RUnlock()
+	for _, fn := range hooks {
+		go fn(e)
+	}
+}

hook_test.go

@@ -0,0 +1,73 @@
+// Copyright (c) Jeevanandam M (https://github.com/jeevatkm)
+// go-aah/log source code and usage is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package log
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	config "aahframework.org/config.v0"
+	"aahframework.org/test.v0/assert"
+)
+
+func TestLogAddHook(t *testing.T) {
+	err := AddHook("hook1", func(e Entry) {
+		assert.NotNil(t, e)
+	})
+	assert.Nil(t, err)
+
+	err = AddHook("hook2", func(e Entry) {
+		assert.NotNil(t, e)
+	})
+	assert.Nil(t, err)
+
+	// Already added
+	err = AddHook("hook1", func(e Entry) {
+		assert.NotNil(t, e)
+	})
+	assert.Equal(t, "log: hook name 'hook1' is already added, skip it", err.Error())
+
+	// Nil hook
+	err = AddHook("nilhook", nil)
+	assert.Equal(t, ErrHookFuncIsNil, err)
+}
+
+func TestLogHook(t *testing.T) {
+	// Add hook
+	_ = AddHook("hook1", func(e Entry) {
+		assert.NotNil(t, e)
+		fmt.Println(e)
+	})
+
+	configStr := `
+  log {
+    receiver = "console"
+    level = "debug"
+    pattern = "%utctime:2006-01-02 15:04:05.000 %level:-5 %line %custom:- %message"
+  }
+  `
+	testHooks(t, configStr)
+	time.Sleep(1 * time.Millisecond)
+}
+
+func testHooks(t *testing.T, cfgStr string) {
+	cfg, _ := config.ParseString(cfgStr)
+	logger, err := New(cfg)
+	assert.FailNowOnError(t, err, "unexpected error")
+
+	logger.Trace("I shoudn't see this msg, because standard logger level is DEBUG")
+	logger.Debug("I would like to see this message, debug is useful for dev")
+	logger.Info("Yes, I would love to see")
+	logger.Warn("Yes, yes it's an warning")
+	logger.Error("Yes, yes, yes - finally an error")
+
+	exit = func(code int) {}
+	logger.Fatal("Yes, yes, yes - at last fatal")
+	exit = os.Exit
+
+	assert.NotNil(t, logger.ToGoLogger())
+}

log.go

@@ -333,4 +333,7 @@ func (l *Logger) output(level level, calldepth int, format *string, v ...interfa
 	}
 
 	l.receiver.Log(entry)
+
+	// Execute logger hooks
+	go executeHooks(*entry)
 }