Update logger implementation

- Added WithLogConfig bootstrap option to create the logger after the metrics and be able to register the metrics log-level counter.
- Added logutil utility function to return the log level name.
- Moved logutil hook logic to a separate file.

Author: nicolaasuni

examples/service/cmd/main.go

@@ -23,6 +23,7 @@ var (
 var exitFn = os.Exit //nolint:gochecknoglobals
 
 func main() {
+	// set default logger
 	logattr := []logutil.Attr{
 		slog.String("program", cli.AppName),
 		slog.String("version", programVersion),

examples/service/internal/cli/cli.go

@@ -13,7 +13,6 @@ import (
 	"github.com/tecnickcom/gogen/pkg/bootstrap"
 	"github.com/tecnickcom/gogen/pkg/config"
 	"github.com/tecnickcom/gogen/pkg/httputil/jsendx"
-	"github.com/tecnickcom/gogen/pkg/logsrv"
 	"github.com/tecnickcom/gogen/pkg/logutil"
 )
 
@@ -34,6 +33,7 @@ func New(version, release string, bootstrapFn bootstrapFunc) (*cobra.Command, er
 		}
 	)
 
+	// command-line arguments
 	rootCmd.Flags().StringVarP(&argConfigDir, "configDir", "c", "", "Configuration directory to be added on top of the search list")
 	rootCmd.Flags().StringVarP(&argLogFormat, "logFormat", "f", "", "Logging format: CONSOLE, JSON")
 	rootCmd.Flags().StringVarP(&argLogLevel, "logLevel", "o", "", "Log level: EMERGENCY, ALERT, CRITICAL, ERROR, WARNING, NOTICE, INFO, DEBUG")
@@ -47,6 +47,8 @@ func New(version, release string, bootstrapFn bootstrapFunc) (*cobra.Command, er
 			return fmt.Errorf("failed loading config: %w", err)
 		}
 
+		// Configure logger
+
 		if argLogFormat != "" {
 			cfg.Log.Format = argLogFormat
 		}
@@ -65,7 +67,6 @@ func New(version, release string, bootstrapFn bootstrapFunc) (*cobra.Command, er
 			return fmt.Errorf("log config error: %w", err)
 		}
 
-		// Configure logger
 		logattr := []logutil.Attr{
 			slog.String("program", AppName),
 			slog.String("version", version),
@@ -78,19 +79,15 @@ func New(version, release string, bootstrapFn bootstrapFunc) (*cobra.Command, er
 			logutil.WithLevel(logLevel),
 			logutil.WithCommonAttr(logattr...),
 		)
-		// if err != nil {
-		// 	return fmt.Errorf("failed configuring logger: %w", err)
-		// }
-
-		l := logsrv.NewLogger(logcfg)
 
 		appInfo := &jsendx.AppInfo{
 			ProgramName:    AppName,
 			ProgramVersion: version,
 			ProgramRelease: release,
 		}
 
-		// Confifure metrics
+		// Initialize metrics
+
 		mtr := metrics.New()
 
 		// Wait group used for graceful shutdown of all dependants (e.g.: servers).
@@ -102,7 +99,7 @@ func New(version, release string, bootstrapFn bootstrapFunc) (*cobra.Command, er
 		// Boostrap application
 		return bootstrapFn(
 			bind(cfg, appInfo, mtr, wg, sc),
-			bootstrap.WithLogger(l),
+			bootstrap.WithLogConfig(logcfg),
 			bootstrap.WithCreateMetricsClientFunc(mtr.CreateMetricsClientFunc),
 			bootstrap.WithShutdownTimeout(time.Duration(cfg.ShutdownTimeout)*time.Second),
 			bootstrap.WithShutdownWaitGroup(wg),

pkg/bootstrap/bootstrap.go

@@ -18,6 +18,8 @@ import (
 	"sync"
 	"syscall"
 	"time"
+
+	"github.com/tecnickcom/gogen/pkg/logutil"
 )
 
 // Bootstrap is the function in charge of configuring the core components
@@ -43,6 +45,13 @@ func Bootstrap(bindFn BindFunc, opts ...Option) error {
 		return fmt.Errorf("error creating application metric: %w", err)
 	}
 
+	if cfg.logConfig != nil {
+		// metric hook to count logs by level
+		cfg.logConfig.HookFn = func(level logutil.LogLevel, _ string) {
+			m.IncLogLevelCounter(logutil.LevelName(level))
+		}
+	}
+
 	l := cfg.createLoggerFunc()
 
 	l.Debug("binding application components")

pkg/bootstrap/bootstrap_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/tecnickcom/gogen/pkg/logutil"
 	"github.com/tecnickcom/gogen/pkg/metrics"
 	"github.com/tecnickcom/gogen/pkg/metrics/prometheus"
 )
@@ -69,6 +70,7 @@ func TestBootstrap(t *testing.T) {
 		{
 			name: "should succeed and exit with SIGTERM",
 			opts: []Option{
+				WithLogConfig(logutil.DefaultConfig()),
 				WithShutdownTimeout(1 * time.Millisecond),
 				WithShutdownWaitGroup(shutdownWG),
 				WithShutdownSignalChan(shutdownSG),
@@ -106,13 +108,6 @@ func TestBootstrap(t *testing.T) {
 			}
 			opts = append(opts, tt.opts...)
 
-			if tt.createLoggerFunc != nil {
-				opts = append(opts, WithCreateLoggerFunc(tt.createLoggerFunc))
-			} else {
-				fn := slog.Default
-				opts = append(opts, WithCreateLoggerFunc(fn))
-			}
-
 			if tt.createMetricsClientFunc != nil {
 				opts = append(opts, WithCreateMetricsClientFunc(tt.createMetricsClientFunc))
 			} else {

pkg/bootstrap/config.go

@@ -7,6 +7,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/tecnickcom/gogen/pkg/logsrv"
+	"github.com/tecnickcom/gogen/pkg/logutil"
 	"github.com/tecnickcom/gogen/pkg/metrics"
 )
 
@@ -24,6 +26,9 @@ type config struct {
 	// context is the application context.
 	context context.Context //nolint:containedctx
 
+	// logConfig stores the logger configuration
+	logConfig *logutil.Config
+
 	// createLoggerFunc is the function used to create a new logger.
 	createLoggerFunc CreateLoggerFunc
 
@@ -44,6 +49,7 @@ type config struct {
 func defaultConfig() *config {
 	return &config{
 		context:                 context.Background(),
+		logConfig:               nil,
 		createLoggerFunc:        defaultCreateLogger,
 		createMetricsClientFunc: defaultCreateMetricsClientFunc,
 		shutdownTimeout:         30 * time.Second,
@@ -62,6 +68,11 @@ func defaultCreateMetricsClientFunc() (metrics.Client, error) {
 	return &metrics.Default{}, nil
 }
 
+// newLogger returs a nes slog logger with the logConfig settings.
+func (c *config) newLogger() *slog.Logger {
+	return logsrv.NewLogger(c.logConfig)
+}
+
 // validate the configuration.
 func (c *config) validate() error {
 	if c.context == nil {

pkg/bootstrap/config_test.go

@@ -12,6 +12,7 @@ func Test_defaultConfig(t *testing.T) {
 	cfg := defaultConfig()
 	require.NotNil(t, cfg)
 	require.NotNil(t, cfg.context)
+	require.Nil(t, cfg.logConfig)
 	require.NotNil(t, cfg.createLoggerFunc)
 	require.NotNil(t, cfg.createMetricsClientFunc)
 }

pkg/bootstrap/options.go

@@ -5,6 +5,8 @@ import (
 	"log/slog"
 	"sync"
 	"time"
+
+	"github.com/tecnickcom/gogen/pkg/logutil"
 )
 
 // Option is a type alias for a function that configures the application logger.
@@ -17,7 +19,17 @@ func WithContext(ctx context.Context) Option {
 	}
 }
 
+// WithLogConfig sets the log configuration options.
+// This should be used in alternative to WithLogger and WithCreateLoggerFunc.
+func WithLogConfig(c *logutil.Config) Option {
+	return func(cfg *config) {
+		cfg.logConfig = c
+		cfg.createLoggerFunc = cfg.newLogger
+	}
+}
+
 // WithLogger overrides the default application logger.
+// This should be used in alternative to WithLogConfig and WithCreateLoggerFunc.
 func WithLogger(l *slog.Logger) Option {
 	return func(cfg *config) {
 		cfg.createLoggerFunc = func() *slog.Logger {
@@ -27,6 +39,7 @@ func WithLogger(l *slog.Logger) Option {
 }
 
 // WithCreateLoggerFunc overrides the root logger creation function.
+// This should be used in alternative to WithLogConfig and WithLogger.
 func WithCreateLoggerFunc(fn CreateLoggerFunc) Option {
 	return func(cfg *config) {
 		cfg.createLoggerFunc = fn

pkg/bootstrap/options_test.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/require"
+	"github.com/tecnickcom/gogen/pkg/logutil"
 	"github.com/tecnickcom/gogen/pkg/metrics"
 )
 
@@ -24,6 +25,18 @@ func TestWithContext(t *testing.T) {
 	require.Equal(t, v, cfg.context)
 }
 
+func TestWithLogConfig(t *testing.T) {
+	t.Parallel()
+
+	cfg := &config{}
+
+	lc := logutil.DefaultConfig()
+
+	WithLogConfig(lc)(cfg)
+	require.Equal(t, lc, cfg.logConfig)
+	require.NotNil(t, cfg.createLoggerFunc)
+}
+
 func TestWithLogger(t *testing.T) {
 	t.Parallel()
 

pkg/logutil/config.go

@@ -1,7 +1,6 @@
 package logutil
 
 import (
-	"context"
 	"io"
 	"log/slog"
 	"os"
@@ -10,12 +9,6 @@ import (
 // Attr is a type alias for slog.Attr.
 type Attr = slog.Attr
 
-// HookFunc is an adaptor to allow the use of an ordinary function as a Hook.
-// The argument is the log level.
-
-// HookFunc is used to intercept the log message before passing it to the underlying handler.
-type HookFunc func(level LogLevel, message string)
-
 // Config holds common logger parameters.
 type Config struct {
 	Out        io.Writer
@@ -83,26 +76,11 @@ func (c *Config) SlogHandler() slog.Handler {
 		h = slog.NewJSONHandler(os.Stderr, nil)
 	}
 
+	h = h.WithAttrs(c.CommonAttr)
+
 	if c.HookFn != nil {
-		h = &SlogHookHandler{
-			Handler: h,
-			hookFn:  c.HookFn,
-		}
+		h = NewSlogHookHandler(h, c.HookFn)
 	}
 
-	return h.WithAttrs(c.CommonAttr)
-}
-
-// SlogHookHandler is a slog.Handler that wraps another handler to add custom logic.
-type SlogHookHandler struct {
-	slog.Handler
-
-	hookFn HookFunc
-}
-
-// Handle intercepts the log record, modifies the message, and then passes
-// it to the underlying handler.
-func (h SlogHookHandler) Handle(ctx context.Context, record slog.Record) error {
-	h.hookFn(record.Level, record.Message)
-	return h.Handler.Handle(ctx, record) //nolint:wrapcheck
+	return h
 }

pkg/logutil/hook.go

@@ -0,0 +1,31 @@
+package logutil
+
+import (
+	"context"
+	"log/slog"
+)
+
+// HookFunc is used to intercept the log message before passing it to the underlying handler.
+type HookFunc func(level LogLevel, message string)
+
+// SlogHookHandler is a slog.Handler that wraps another handler to add custom logic.
+type SlogHookHandler struct {
+	slog.Handler
+
+	hookFn HookFunc
+}
+
+// NewSlogHookHandler adds a hook function to the slog Handler.
+func NewSlogHookHandler(h slog.Handler, f HookFunc) *SlogHookHandler {
+	return &SlogHookHandler{
+		Handler: h,
+		hookFn:  f,
+	}
+}
+
+// Handle intercepts the log record, modifies the message, and then passes
+// it to the underlying handler.
+func (h SlogHookHandler) Handle(ctx context.Context, record slog.Record) error {
+	h.hookFn(record.Level, record.Message)
+	return h.Handler.Handle(ctx, record) //nolint:wrapcheck
+}