Move logger into dedicated utility module

go.mod

@@ -1,6 +1,6 @@
 module github.com/StackAdapt/systags
 
-go 1.19
+go 1.21
 
 require (
 	github.com/aws/aws-sdk-go-v2 v1.19.0

main.go

@@ -1,45 +1,27 @@
 package main
 
 import (
-	"context"
-	"log"
+	"log/slog"
 	"os"
 
-	"github.com/fatih/color"
-	"golang.org/x/exp/slog"
-
 	"github.com/StackAdapt/systags/command"
 	"github.com/StackAdapt/systags/manager"
+	"github.com/StackAdapt/systags/utility"
 )
 
-type LogHandler struct {
-	slog.Handler
-	out *log.Logger
-	err *log.Logger
-}
-
-func (log *LogHandler) Handle(_ context.Context, r slog.Record) error {
-
-	switch r.Level {
-	case slog.LevelDebug:
-		log.out.Println(color.HiBlackString(r.Message))
-
-	case slog.LevelInfo:
-		log.out.Println(r.Message)
+func main() {
 
-	case slog.LevelWarn:
-		log.err.Println(color.YellowString(r.Message))
+	m := manager.NewManager()
 
-	case slog.LevelError:
-		log.err.Println(color.RedString(r.Message))
+	var level slog.Level
+	if os.Getenv("SYSTAGS_DEBUG") == "" {
+		level = slog.LevelInfo
+	} else {
+		level = slog.LevelDebug
 	}
 
-	return nil
-}
-
-func main() {
-
-	m := manager.NewManager()
+	logger := utility.NewLogger(level)
+	m.SetLogger(logger)
 
 	configDir := os.Getenv("SYSTAGS_CONFIG_DIR")
 	systemDir := os.Getenv("SYSTAGS_SYSTEM_DIR")
@@ -52,25 +34,6 @@ func main() {
 		m.SystemDir = systemDir
 	}
 
-	var level slog.Level
-	if os.Getenv("SYSTAGS_DEBUG") == "" {
-		level = slog.LevelInfo
-	} else {
-		level = slog.LevelDebug
-	}
-
-	loggerOpts := &slog.HandlerOptions{
-		Level: level,
-	}
-
-	logger := slog.New(&LogHandler{
-		Handler: slog.NewTextHandler(os.Stdout, loggerOpts),
-		out:     log.New(os.Stdout, "", 0),
-		err:     log.New(os.Stderr, "", 0),
-	})
-
-	m.SetLogger(logger)
-
 	// Perform CLI parsing, errors are logged using logger
 	if err := command.ParseArgs(m, os.Args); err != nil {
 		os.Exit(1)

manager/aws.go

@@ -4,11 +4,10 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"strings"
 	"time"
 
-	"golang.org/x/exp/slog"
-
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/feature/ec2/imds"

manager/manager.go

@@ -3,13 +3,12 @@ package manager
 import (
 	"encoding/json"
 	"fmt"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
 	"time"
-
-	"golang.org/x/exp/slog"
 )
 
 // Tags describe a map of key/value pairs
@@ -45,9 +44,9 @@ func NewManager() *Manager {
 	m := Manager{
 		ConfigDir: "/etc/systags.d",
 		SystemDir: "/var/lib/systags",
-		logger:    slog.Default(),
 	}
 
+	m.SetLogger(nil)
 	m.Reset()
 
 	return &m
@@ -84,6 +83,8 @@ func (m *Manager) Reset() {
 // Manager's internal config, remote, and system tags.
 func (m *Manager) LoadFiles() error {
 
+	logger := m.GetLogger()
+
 	configData := make(Tags)
 	remoteData := make(Tags)
 	systemData := make(Tags)
@@ -93,7 +94,7 @@ func (m *Manager) LoadFiles() error {
 
 	if err == nil {
 
-		m.logger.Debug("reading config directory: " + m.ConfigDir)
+		logger.Debug("reading config directory: " + m.ConfigDir)
 
 		// Iterate through all config files
 		for _, file := range configFiles {
@@ -112,7 +113,7 @@ func (m *Manager) LoadFiles() error {
 			// Construct the full path to the current config file
 			configFile := filepath.Join(m.ConfigDir, file.Name())
 
-			m.logger.Debug(configFile)
+			logger.Debug(configFile)
 
 			// Attempt to read the contents of the file
 			configBytes, err := os.ReadFile(configFile)
@@ -141,7 +142,7 @@ func (m *Manager) LoadFiles() error {
 	// Check if remote file exists and then read it
 	if _, err := os.Stat(remoteFile); err == nil {
 
-		m.logger.Debug("reading remote file: " + remoteFile)
+		logger.Debug("reading remote file: " + remoteFile)
 
 		// Attempt to read the contents of the file
 		remoteBytes, err := os.ReadFile(remoteFile)
@@ -159,7 +160,7 @@ func (m *Manager) LoadFiles() error {
 	// Check if system file exists and then read it
 	if _, err := os.Stat(systemFile); err == nil {
 
-		m.logger.Debug("reading system file: " + systemFile)
+		logger.Debug("reading system file: " + systemFile)
 
 		// Attempt to read the contents of the file
 		systemBytes, err := os.ReadFile(systemFile)
@@ -187,6 +188,8 @@ func (m *Manager) LoadFiles() error {
 // to create a backup of the existing files.
 func (m *Manager) SaveFiles() error {
 
+	logger := m.GetLogger()
+
 	// Construct the full path to the system directory files
 	remoteFile := filepath.Join(m.SystemDir, "remote.json")
 	systemFile := filepath.Join(m.SystemDir, "system.json")
@@ -208,7 +211,7 @@ func (m *Manager) SaveFiles() error {
 
 		remoteBackup := remoteFile + ".bak"
 
-		m.logger.Debug("writing remote backup: " + remoteBackup)
+		logger.Debug("writing remote backup: " + remoteBackup)
 
 		// Attempt to read the contents of the file
 		remoteBytes, err := os.ReadFile(remoteFile)
@@ -228,7 +231,7 @@ func (m *Manager) SaveFiles() error {
 
 		systemBackup := systemFile + ".bak"
 
-		m.logger.Debug("writing system backup: " + systemBackup)
+		logger.Debug("writing system backup: " + systemBackup)
 
 		// Attempt to read the contents of the file
 		systemBytes, err := os.ReadFile(systemFile)
@@ -243,15 +246,15 @@ func (m *Manager) SaveFiles() error {
 		}
 	}
 
-	m.logger.Debug("writing remote file: " + remoteFile)
+	logger.Debug("writing remote file: " + remoteFile)
 
 	// Attempt to write the current tag content
 	err = os.WriteFile(remoteFile, remoteJson, 0666)
 	if err != nil {
 		return err
 	}
 
-	m.logger.Debug("writing system file: " + systemFile)
+	logger.Debug("writing system file: " + systemFile)
 
 	// Attempt to write the current tag content
 	err = os.WriteFile(systemFile, systemJson, 0666)
@@ -274,7 +277,7 @@ func (m *Manager) UpdateRemote(timeout time.Duration) error {
 	// which cloud provider is being used and add the feature
 	// to update the tags similar to how it's done now in AWS.
 
-	result, err := getAwsTags(m.logger, timeout)
+	result, err := getAwsTags(m.GetLogger(), timeout)
 	if err != nil {
 		return err
 	}

utility/logger.go

@@ -0,0 +1,78 @@
+package utility
+
+import (
+	"context"
+	"log"
+	"log/slog"
+	"os"
+
+	"github.com/fatih/color"
+)
+
+// ColorWriter is a custom writer that adds color to the output.
+type ColorWriter struct {
+	w     *os.File
+	color *color.Color
+}
+
+func (cw *ColorWriter) Write(p []byte) (n int, err error) {
+	return cw.w.Write([]byte(cw.color.Sprint(string(p))))
+}
+
+// LogHandler is a custom slog handler that routes log messages to different
+// loggers based on their severity level. It embeds slog.Handler and defines
+// loggers for different severity levels like Debug, Info, Warn, and Error.
+type LogHandler struct {
+	slog.Handler
+	Debug *log.Logger
+	Info  *log.Logger
+	Warn  *log.Logger
+	Error *log.Logger
+}
+
+func (log *LogHandler) Handle(_ context.Context, r slog.Record) error {
+
+	switch r.Level {
+	case slog.LevelDebug:
+		log.Debug.Println(r.Message)
+
+	case slog.LevelInfo:
+		log.Info.Println(r.Message)
+
+	case slog.LevelWarn:
+		log.Warn.Println(r.Message)
+
+	case slog.LevelError:
+		log.Error.Println(r.Message)
+	}
+
+	return nil
+}
+
+// NewLogger creates a new instance of slog.Logger. The logging level can be
+// specified by level. The returned logger writes info messages to STDOUT and
+// warning, error, and debug messages to STDERR. The messages are color-coded
+// for readability: debug messages are light gray, warning messages are yellow,
+// and error messages are red.
+func NewLogger(level slog.Level) *slog.Logger {
+
+	options := &slog.HandlerOptions{
+		Level: level,
+	}
+
+	cwDebug := &ColorWriter{w: os.Stderr, color: color.New(color.FgHiBlack)}
+	cwInfo := &ColorWriter{w: os.Stdout, color: color.New()}
+	cwWarn := &ColorWriter{w: os.Stderr, color: color.New(color.FgYellow)}
+	cwError := &ColorWriter{w: os.Stderr, color: color.New(color.FgRed)}
+
+	logger := slog.New(&LogHandler{
+		Handler: slog.NewTextHandler(os.Stdout, options),
+
+		Debug: log.New(cwDebug, "", 0),
+		Info:  log.New(cwInfo, "", 0),
+		Warn:  log.New(cwWarn, "", 0),
+		Error: log.New(cwError, "", 0),
+	})
+
+	return logger
+}