feat: add configurable --log-level flag (#5934)

Signed-off-by: boojack <stevenlgtm@gmail.com>
Co-authored-by: boojack <stevenlgtm@gmail.com>

cmd/memos/log.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"io"
+	"log/slog"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+func parseSlogLevel(s string) (slog.Level, error) {
+	switch strings.ToLower(s) {
+	case "debug":
+		return slog.LevelDebug, nil
+	case "info":
+		return slog.LevelInfo, nil
+	case "warn":
+		return slog.LevelWarn, nil
+	case "error":
+		return slog.LevelError, nil
+	default:
+		return slog.LevelInfo, errors.Errorf("unknown log level %q: must be debug, info, warn, or error", s)
+	}
+}
+
+func newLogger(level slog.Level, w io.Writer) *slog.Logger {
+	return slog.New(slog.NewTextHandler(w, &slog.HandlerOptions{Level: level}))
+}

cmd/memos/log_test.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"log/slog"
+	"strings"
+	"testing"
+)
+
+func TestParseSlogLevel(t *testing.T) {
+	tests := []struct {
+		input     string
+		wantLevel slog.Level
+		wantErr   bool
+	}{
+		{"debug", slog.LevelDebug, false},
+		{"info", slog.LevelInfo, false},
+		{"warn", slog.LevelWarn, false},
+		{"error", slog.LevelError, false},
+		{"DEBUG", slog.LevelDebug, false},
+		{"INFO", slog.LevelInfo, false},
+		{"WARN", slog.LevelWarn, false},
+		{"ERROR", slog.LevelError, false},
+		{"invalid", slog.LevelInfo, true},
+		{"", slog.LevelInfo, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got, err := parseSlogLevel(tt.input)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseSlogLevel(%q) error = %v, wantErr %v", tt.input, err, tt.wantErr)
+			}
+			if got != tt.wantLevel {
+				t.Errorf("parseSlogLevel(%q) = %v, want %v", tt.input, got, tt.wantLevel)
+			}
+		})
+	}
+}
+
+func TestNewLoggerLevelFiltering(t *testing.T) {
+	tests := []struct {
+		level        slog.Level
+		logAt        slog.Level
+		msg          string
+		shouldAppear bool
+	}{
+		// debug passes all
+		{slog.LevelDebug, slog.LevelDebug, "debug-msg", true},
+		{slog.LevelDebug, slog.LevelInfo, "info-msg", true},
+		{slog.LevelDebug, slog.LevelWarn, "warn-msg", true},
+		{slog.LevelDebug, slog.LevelError, "error-msg", true},
+		// info suppresses debug
+		{slog.LevelInfo, slog.LevelDebug, "debug-suppressed", false},
+		{slog.LevelInfo, slog.LevelInfo, "info-visible", true},
+		{slog.LevelInfo, slog.LevelWarn, "warn-visible", true},
+		// warn suppresses debug+info
+		{slog.LevelWarn, slog.LevelDebug, "debug-suppressed", false},
+		{slog.LevelWarn, slog.LevelInfo, "info-suppressed", false},
+		{slog.LevelWarn, slog.LevelWarn, "warn-visible", true},
+		{slog.LevelWarn, slog.LevelError, "error-visible", true},
+		// error suppresses everything below
+		{slog.LevelError, slog.LevelDebug, "debug-suppressed", false},
+		{slog.LevelError, slog.LevelInfo, "info-suppressed", false},
+		{slog.LevelError, slog.LevelWarn, "warn-suppressed", false},
+		{slog.LevelError, slog.LevelError, "error-visible", true},
+	}
+
+	for _, tt := range tests {
+		var buf bytes.Buffer
+		logger := newLogger(tt.level, &buf)
+		logger.Log(context.TODO(), tt.logAt, tt.msg)
+
+		appeared := strings.Contains(buf.String(), tt.msg)
+		if appeared != tt.shouldAppear {
+			t.Errorf("level=%s logAt=%s msg=%q: appeared=%v want=%v",
+				tt.level, tt.logAt, tt.msg, appeared, tt.shouldAppear)
+		}
+	}
+}
+
+func TestNewLoggerOutputFormat(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newLogger(slog.LevelDebug, &buf)
+	logger.Info("hello-world", "key", "value")
+
+	out := buf.String()
+	if !strings.Contains(out, "hello-world") {
+		t.Errorf("expected message in output, got: %s", out)
+	}
+	if !strings.Contains(out, "key=value") {
+		t.Errorf("expected key=value attr in output, got: %s", out)
+	}
+	if !strings.Contains(out, "INFO") {
+		t.Errorf("expected level in output, got: %s", out)
+	}
+}
+
+func TestNewLoggerDoesNotMutateGlobalDefault(t *testing.T) {
+	original := slog.Default()
+	var buf bytes.Buffer
+	_ = newLogger(slog.LevelError, &buf)
+	if slog.Default() != original {
+		t.Error("newLogger must not change slog.Default()")
+	}
+}

cmd/memos/main.go

@@ -21,6 +21,14 @@ import (
 	"github.com/usememos/memos/store/db"
 )
 
+func initSlogDefault() {
+	level, err := parseSlogLevel(viper.GetString("log-level"))
+	if err != nil {
+		slog.Warn("invalid log-level value, defaulting to info", "error", err)
+	}
+	slog.SetDefault(newLogger(level, os.Stderr))
+}
+
 var (
 	rootCmd = &cobra.Command{
 		Use:   "memos",
@@ -103,6 +111,8 @@ var (
 )
 
 func init() {
+	cobra.OnInitialize(initSlogDefault)
+
 	viper.SetDefault("demo", false)
 	viper.SetDefault("driver", "sqlite")
 	viper.SetDefault("port", 8081)
@@ -116,6 +126,7 @@ func init() {
 	rootCmd.PersistentFlags().String("dsn", "", "database source name(aka. DSN)")
 	rootCmd.PersistentFlags().String("instance-url", "", "the url of your memos instance")
 	rootCmd.PersistentFlags().Bool("allow-private-webhooks", false, "allow webhook URLs to resolve to private/reserved IP addresses")
+	rootCmd.PersistentFlags().String("log-level", "info", "log verbosity level (debug, info, warn, error)")
 
 	if err := viper.BindPFlag("demo", rootCmd.PersistentFlags().Lookup("demo")); err != nil {
 		panic(err)
@@ -144,6 +155,9 @@ func init() {
 	if err := viper.BindPFlag("allow-private-webhooks", rootCmd.PersistentFlags().Lookup("allow-private-webhooks")); err != nil {
 		panic(err)
 	}
+	if err := viper.BindPFlag("log-level", rootCmd.PersistentFlags().Lookup("log-level")); err != nil {
+		panic(err)
+	}
 
 	viper.SetEnvPrefix("memos")
 	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))