refactor: redesign logging system for CLI-friendly output (#561)

* refactor: redesign logging system for CLI-friendly output
* refactor: remove ANSI color support from logger
* fix: address PR review feedback

CLAUDE.md

@@ -46,7 +46,7 @@ go mod verify
 
 - **Platform code**: use build tags (`_darwin.go`, `_windows.go`, `_linux.go`)
 - **Error handling**: `fmt.Errorf("context: %w", err)` for wrapping, never `_ =` to ignore errors
-- **Logging**: `log.Debugf` for record-level issues, `log.Warnf` for user-visible warnings. Extract methods should return errors, not log them.
+- **Logging**: `log.Debugf` for record-level diagnostics, `log.Infof` for user-facing progress/status, `log.Warnf` for unexpected conditions. Extract methods should return errors, not log them.
 - **Naming**: follow Go conventions — `Config` not `BrowserConfig`, `Extract` not `BrowsingData`
 - **Tests**: use `t.TempDir()` for filesystem tests, `go-sqlmock` for database tests
 - **Architecture**: see `rfcs/` for design documents

browser/chromium/chromium.go

@@ -187,7 +187,6 @@ func (b *Browser) extractCategory(data *types.BrowserData, cat types.Category, m
 func discoverProfiles(userDataDir string, sources map[types.Category][]sourcePath) []string {
 	entries, err := os.ReadDir(userDataDir)
 	if err != nil {
-		log.Debugf("read user data dir %s: %v", userDataDir, err)
 		return nil
 	}
 

browser/chromium/extract_cookie.go

@@ -16,6 +16,8 @@ const defaultCookieQuery = `SELECT name, encrypted_value, host_key, path,
 	has_expires, is_persistent FROM cookies`
 
 func extractCookies(masterKey []byte, path string) ([]types.CookieEntry, error) {
+	var decryptFails int
+	var lastErr error
 	cookies, err := sqliteutil.QueryRows(path, false, defaultCookieQuery,
 		func(rows *sql.Rows) (types.CookieEntry, error) {
 			var (
@@ -33,7 +35,8 @@ func extractCookies(masterKey []byte, path string) ([]types.CookieEntry, error)
 
 			value, err := decryptValue(masterKey, encryptedValue)
 			if err != nil {
-				log.Debugf("decrypt cookie %s on %s: %v", name, host, err)
+				decryptFails++
+				lastErr = err
 			}
 			value = stripCookieHash(value, host)
 			return types.CookieEntry{
@@ -52,6 +55,9 @@ func extractCookies(masterKey []byte, path string) ([]types.CookieEntry, error)
 	if err != nil {
 		return nil, err
 	}
+	if decryptFails > 0 {
+		log.Debugf("decrypt cookies: %d failed: %v", decryptFails, lastErr)
+	}
 
 	sort.Slice(cookies, func(i, j int) bool {
 		return cookies[i].CreatedAt.After(cookies[j].CreatedAt)

browser/chromium/extract_creditcard.go

@@ -12,7 +12,9 @@ const defaultCreditCardQuery = `SELECT COALESCE(guid, ''), name_on_card, expirat
 	card_number_encrypted, COALESCE(nickname, ''), COALESCE(billing_address_id, '') FROM credit_cards`
 
 func extractCreditCards(masterKey []byte, path string) ([]types.CreditCardEntry, error) {
-	return sqliteutil.QueryRows(path, false, defaultCreditCardQuery,
+	var decryptFails int
+	var lastErr error
+	cards, err := sqliteutil.QueryRows(path, false, defaultCreditCardQuery,
 		func(rows *sql.Rows) (types.CreditCardEntry, error) {
 			var guid, name, month, year, nickname, address string
 			var encNumber []byte
@@ -21,7 +23,8 @@ func extractCreditCards(masterKey []byte, path string) ([]types.CreditCardEntry,
 			}
 			number, err := decryptValue(masterKey, encNumber)
 			if err != nil {
-				log.Debugf("decrypt credit card for %s: %v", name, err)
+				decryptFails++
+				lastErr = err
 			}
 			return types.CreditCardEntry{
 				GUID:     guid,
@@ -33,4 +36,11 @@ func extractCreditCards(masterKey []byte, path string) ([]types.CreditCardEntry,
 				Address:  address,
 			}, nil
 		})
+	if err != nil {
+		return nil, err
+	}
+	if decryptFails > 0 {
+		log.Debugf("decrypt credit cards: %d failed: %v", decryptFails, lastErr)
+	}
+	return cards, nil
 }

browser/chromium/extract_password.go

@@ -16,6 +16,8 @@ func extractPasswords(masterKey []byte, path string) ([]types.LoginEntry, error)
 }
 
 func extractPasswordsWithQuery(masterKey []byte, path, query string) ([]types.LoginEntry, error) {
+	var decryptFails int
+	var lastErr error
 	logins, err := sqliteutil.QueryRows(path, false, query,
 		func(rows *sql.Rows) (types.LoginEntry, error) {
 			var url, username string
@@ -26,7 +28,8 @@ func extractPasswordsWithQuery(masterKey []byte, path, query string) ([]types.Lo
 			}
 			password, err := decryptValue(masterKey, pwd)
 			if err != nil {
-				log.Debugf("decrypt password for %s: %v", url, err)
+				decryptFails++
+				lastErr = err
 			}
 			return types.LoginEntry{
 				URL:       url,
@@ -38,6 +41,9 @@ func extractPasswordsWithQuery(masterKey []byte, path, query string) ([]types.Lo
 	if err != nil {
 		return nil, err
 	}
+	if decryptFails > 0 {
+		log.Debugf("decrypt passwords: %d failed: %v", decryptFails, lastErr)
+	}
 
 	sort.Slice(logins, func(i, j int) bool {
 		return logins[i].CreatedAt.After(logins[j].CreatedAt)

browser/firefox/extract_password.go

@@ -37,6 +37,8 @@ func extractPasswords(masterKey []byte, path string) ([]types.LoginEntry, error)
 	}
 
 	var logins []types.LoginEntry
+	var decryptFails int
+	var lastErr error
 	for _, v := range gjson.GetBytes(data, "logins").Array() {
 		url := v.Get("formSubmitURL").String()
 		if url == "" {
@@ -45,11 +47,13 @@ func extractPasswords(masterKey []byte, path string) ([]types.LoginEntry, error)
 
 		user, err := decryptPBE(v.Get("encryptedUsername").String(), masterKey)
 		if err != nil {
-			log.Debugf("decrypt firefox username for %s: %v", url, err)
+			decryptFails++
+			lastErr = err
 		}
 		pwd, err := decryptPBE(v.Get("encryptedPassword").String(), masterKey)
 		if err != nil {
-			log.Debugf("decrypt firefox password for %s: %v", url, err)
+			decryptFails++
+			lastErr = err
 		}
 
 		logins = append(logins, types.LoginEntry{
@@ -59,6 +63,9 @@ func extractPasswords(masterKey []byte, path string) ([]types.LoginEntry, error)
 			CreatedAt: timestamp(v.Get("timeCreated").Int() / 1000),
 		})
 	}
+	if decryptFails > 0 {
+		log.Debugf("decrypt firefox login fields: %d failed: %v", decryptFails, lastErr)
+	}
 
 	sort.Slice(logins, func(i, j int) bool {
 		return logins[i].CreatedAt.After(logins[j].CreatedAt)

browser/firefox/firefox.go

@@ -188,7 +188,6 @@ type resolvedPath struct {
 func discoverProfiles(userDataDir string, sources map[types.Category][]sourcePath) []string {
 	entries, err := os.ReadDir(userDataDir)
 	if err != nil {
-		log.Debugf("read user data dir %s: %v", userDataDir, err)
 		return nil
 	}
 

cmd/hack-browser-data/dump.go

@@ -58,6 +58,7 @@ func dumpCmd() *cobra.Command {
 			}
 
 			for _, b := range browsers {
+				log.Infof("Extracting %s/%s...", b.BrowserName(), b.ProfileName())
 				data, extractErr := b.Extract(categories)
 				if extractErr != nil {
 					log.Errorf("extract %s/%s: %v", b.BrowserName(), b.ProfileName(), extractErr)
@@ -73,7 +74,7 @@ func dumpCmd() *cobra.Command {
 				if err := fileutil.CompressDir(outputDir); err != nil {
 					return fmt.Errorf("compress: %w", err)
 				}
-				log.Warnf("compressed: %s/%s.zip", outputDir, filepath.Base(outputDir))
+				log.Infof("Compressed: %s/%s.zip", outputDir, filepath.Base(outputDir))
 			}
 			return nil
 		},

log/level.go

@@ -1,6 +1,6 @@
-package level
+package log
 
-// Level defines all the available levels we can log at
+// Level defines all the available levels we can log at.
 type Level int32
 
 const (
@@ -8,6 +8,9 @@ const (
 	// Debug logs are intended for debugging and development purposes.
 	DebugLevel Level = iota + 1
 
+	// InfoLevel is used for user-facing progress and status messages.
+	InfoLevel
+
 	// WarnLevel is used for undesired but relatively expected events,
 	// which may indicate a problem.
 	WarnLevel
@@ -24,14 +27,16 @@ const (
 func (l Level) String() string {
 	switch l {
 	case DebugLevel:
-		return "DEBUG"
+		return "DBG"
+	case InfoLevel:
+		return "INF"
 	case WarnLevel:
-		return "WARN"
+		return "WRN"
 	case ErrorLevel:
-		return "ERROR"
+		return "ERR"
 	case FatalLevel:
-		return "FATAL"
+		return "FTL"
 	default:
-		return "UNKNOWN"
+		return "???"
 	}
 }

log/log.go

@@ -1,44 +1,52 @@
 package log
 
-import (
-	"github.com/moond4rk/hackbrowserdata/log/level"
-)
+import "fmt"
 
 // defaultLogger is the default logger used by the package-level functions.
 var defaultLogger = NewLogger(nil)
 
 func SetVerbose() {
-	defaultLogger.SetLevel(level.DebugLevel)
+	defaultLogger.SetLevel(DebugLevel)
 }
 
 func Debug(args ...any) {
-	defaultLogger.Debug(args...)
+	defaultLogger.logMsg(DebugLevel, fmt.Sprint(args...))
 }
 
 func Debugf(format string, args ...any) {
-	defaultLogger.Debugf(format, args...)
+	defaultLogger.logMsg(DebugLevel, fmt.Sprintf(format, args...))
+}
+
+func Info(args ...any) {
+	defaultLogger.logMsg(InfoLevel, fmt.Sprint(args...))
+}
+
+func Infof(format string, args ...any) {
+	defaultLogger.logMsg(InfoLevel, fmt.Sprintf(format, args...))
 }
 
 func Warn(args ...any) {
-	defaultLogger.Warn(args...)
+	defaultLogger.logMsg(WarnLevel, fmt.Sprint(args...))
 }
 
 func Warnf(format string, args ...any) {
-	defaultLogger.Warnf(format, args...)
+	defaultLogger.logMsg(WarnLevel, fmt.Sprintf(format, args...))
 }
 
 func Error(args ...any) {
-	defaultLogger.Error(args...)
+	defaultLogger.logMsg(ErrorLevel, fmt.Sprint(args...))
 }
 
 func Errorf(format string, args ...any) {
-	defaultLogger.Errorf(format, args...)
+	defaultLogger.logMsg(ErrorLevel, fmt.Sprintf(format, args...))
 }
 
 func Fatal(args ...any) {
-	defaultLogger.Fatal(args...)
+	defaultLogger.logMsg(FatalLevel, fmt.Sprint(args...))
+	osExit(1)
 }
 
 func Fatalf(format string, args ...any) {
-	defaultLogger.Fatalf(format, args...)
+	defaultLogger.logMsg(FatalLevel, fmt.Sprintf(format, args...))
+	osExit(1)
 }

log/logger.go

@@ -3,180 +3,158 @@ package log
 import (
 	"fmt"
 	"io"
-	stdlog "log"
 	"os"
+	"path/filepath"
 	"runtime"
 	"strings"
+	"sync"
 	"sync/atomic"
-
-	"github.com/moond4rk/hackbrowserdata/log/level"
 )
 
 // NewLogger creates and returns a new instance of Logger.
-// Log level is set to DebugLevel by default.
+// Default level is InfoLevel (Debug messages are suppressed unless SetVerbose is called).
 func NewLogger(base Base) *Logger {
 	if base == nil {
 		base = newBase(os.Stderr)
 	}
-	return &Logger{base: base, minLevel: level.WarnLevel}
+	return &Logger{base: base, minLevel: InfoLevel}
 }
 
-// Logger logs message to io.Writer at various log levels.
+// Logger logs messages to io.Writer at various log levels.
 type Logger struct {
 	base Base
 
 	// Minimum log level for this logger.
-	// Message with level lower than this level won't be outputted.
-	minLevel level.Level
+	// Messages with level lower than this won't be outputted.
+	minLevel Level
 }
 
 // canLogAt reports whether logger can log at level v.
-func (l *Logger) canLogAt(v level.Level) bool {
-	return v >= level.Level(atomic.LoadInt32((*int32)(&l.minLevel)))
+func (l *Logger) canLogAt(v Level) bool {
+	return v >= Level(atomic.LoadInt32((*int32)(&l.minLevel)))
 }
 
 // SetLevel sets the logger level.
 // It panics if v is less than DebugLevel or greater than FatalLevel.
-func (l *Logger) SetLevel(v level.Level) {
-	if v < level.DebugLevel || v > level.FatalLevel {
+func (l *Logger) SetLevel(v Level) {
+	if v < DebugLevel || v > FatalLevel {
 		panic("log: invalid log level")
 	}
 	atomic.StoreInt32((*int32)(&l.minLevel), int32(v))
 }
 
+// baseCallerSkip is the number of frames to skip in runtime.Caller to reach
+// the actual call site. Both package-level functions (log.Xxx -> logMsg -> base.Log)
+// and Logger methods (Logger.Xxx -> logMsg -> base.Log) add exactly one frame
+// above logMsg, so the skip is the same: base.Log(0) -> logMsg(1) -> caller_wrapper(2) -> caller(3).
+const baseCallerSkip = 3
+
+// logMsg is the internal method all public methods delegate to.
+func (l *Logger) logMsg(lvl Level, msg string) {
+	if !l.canLogAt(lvl) {
+		return
+	}
+	l.base.Log(baseCallerSkip, lvl, msg)
+}
+
 func (l *Logger) Debug(args ...any) {
-	if !l.canLogAt(level.DebugLevel) {
-		return
-	}
-	l.base.Debug(args...)
-}
-
-func (l *Logger) Warn(args ...any) {
-	if !l.canLogAt(level.WarnLevel) {
-		return
-	}
-	l.base.Warn(args...)
-}
-
-func (l *Logger) Error(args ...any) {
-	if !l.canLogAt(level.ErrorLevel) {
-		return
-	}
-	l.base.Error(args...)
-}
-
-func (l *Logger) Fatal(args ...any) {
-	if !l.canLogAt(level.FatalLevel) {
-		return
-	}
-	l.base.Fatal(args...)
+	l.logMsg(DebugLevel, fmt.Sprint(args...))
 }
 
 func (l *Logger) Debugf(format string, args ...any) {
-	if !l.canLogAt(level.DebugLevel) {
-		return
-	}
-	l.base.Debug(fmt.Sprintf(format, args...))
+	l.logMsg(DebugLevel, fmt.Sprintf(format, args...))
+}
+
+func (l *Logger) Info(args ...any) {
+	l.logMsg(InfoLevel, fmt.Sprint(args...))
+}
+
+func (l *Logger) Infof(format string, args ...any) {
+	l.logMsg(InfoLevel, fmt.Sprintf(format, args...))
+}
+
+func (l *Logger) Warn(args ...any) {
+	l.logMsg(WarnLevel, fmt.Sprint(args...))
 }
 
 func (l *Logger) Warnf(format string, args ...any) {
-	if !l.canLogAt(level.WarnLevel) {
-		return
-	}
-	l.base.Warn(fmt.Sprintf(format, args...))
+	l.logMsg(WarnLevel, fmt.Sprintf(format, args...))
+}
+
+func (l *Logger) Error(args ...any) {
+	l.logMsg(ErrorLevel, fmt.Sprint(args...))
 }
 
 func (l *Logger) Errorf(format string, args ...any) {
-	if !l.canLogAt(level.ErrorLevel) {
-		return
-	}
-	l.base.Error(fmt.Sprintf(format, args...))
+	l.logMsg(ErrorLevel, fmt.Sprintf(format, args...))
+}
+
+func (l *Logger) Fatal(args ...any) {
+	l.logMsg(FatalLevel, fmt.Sprint(args...))
+	osExit(1)
 }
 
 func (l *Logger) Fatalf(format string, args ...any) {
-	if !l.canLogAt(level.FatalLevel) {
-		return
-	}
-	l.base.Fatal(fmt.Sprintf(format, args...))
+	l.logMsg(FatalLevel, fmt.Sprintf(format, args...))
+	osExit(1)
 }
 
+// Base is the interface that underlies the Logger. It receives the caller
+// skip count, log level, and formatted message.
 type Base interface {
-	Debug(args ...any)
-	Warn(args ...any)
-	Error(args ...any)
-	Fatal(args ...any)
+	Log(callerSkip int, lvl Level, msg string)
 }
 
-// baseLogger is a wrapper object around log.Logger from the standard library.
-// It supports logging at various log levels.
+// baseLogger writes formatted log messages to an io.Writer.
+// Output format:
+//
+//	[DBG] file.go:42: message
+//	[INF] message
+//	[WRN] message
+//	[ERR] message
+//	[FTL] message
 type baseLogger struct {
-	*stdlog.Logger
-	callDepth int
+	out io.Writer
+	mu  sync.Mutex
 }
 
 func newBase(out io.Writer) *baseLogger {
-	prefix := "[hack-browser-data] "
-	base := &baseLogger{
-		Logger: stdlog.New(out, prefix, stdlog.Lshortfile),
-	}
-	base.callDepth = base.calculateCallDepth()
-	return base
-}
-
-// calculateCallDepth returns the call depth for the logger.
-func (l *baseLogger) calculateCallDepth() int {
-	return l.getCallDepth()
-}
-
-func (l *baseLogger) prefixPrint(prefix string, args ...any) {
-	args = append([]any{prefix}, args...)
-	if err := l.Output(l.callDepth, fmt.Sprint(args...)); err != nil {
-		_, _ = fmt.Fprintf(os.Stderr, "log output error: %v\n", err)
-	}
-}
-
-func (l *baseLogger) getCallDepth() int {
-	defaultCallDepth := 2
-	pcs := make([]uintptr, 10)
-	n := runtime.Callers(defaultCallDepth, pcs)
-	frames := runtime.CallersFrames(pcs[:n])
-	for i := 0; i < n; i++ {
-		frame, more := frames.Next()
-		if !l.isLoggerPackage(frame.Function) {
-			return i + 1
-		}
-		if !more {
-			break
-		}
-	}
-	return defaultCallDepth
-}
-
-func (l *baseLogger) isLoggerPackage(funcName string) bool {
-	const loggerFuncName = "hackbrowserdata/log"
-	return strings.Contains(funcName, loggerFuncName)
-}
-
-// Debug logs a message at Debug level.
-func (l *baseLogger) Debug(args ...any) {
-	l.prefixPrint("DEBUG: ", args...)
-}
-
-// Warn logs a message at Warning level.
-func (l *baseLogger) Warn(args ...any) {
-	l.prefixPrint("WARN: ", args...)
-}
-
-// Error logs a message at Error level.
-func (l *baseLogger) Error(args ...any) {
-	l.prefixPrint("ERROR: ", args...)
+	return &baseLogger{out: out}
 }
 
 var osExit = os.Exit
 
-// Fatal logs a message at Fatal level
-// and process will exit with status set to 1.
-func (l *baseLogger) Fatal(args ...any) {
-	l.prefixPrint("FATAL: ", args...)
-	osExit(1)
+// continuation is the indent for multi-line messages.
+// Width matches "[DBG] " (6 chars).
+const continuation = "      "
+
+func (l *baseLogger) Log(callerSkip int, lvl Level, msg string) {
+	msg = strings.TrimRight(msg, "\n")
+	if strings.Contains(msg, "\n") {
+		msg = strings.ReplaceAll(msg, "\n", "\n"+continuation)
+	}
+
+	label := l.formatLabel(lvl)
+	var line string
+	if lvl == DebugLevel {
+		_, file, num, ok := runtime.Caller(callerSkip)
+		if ok {
+			file = filepath.Base(file)
+		} else {
+			file = "???"
+			num = 0
+		}
+		line = fmt.Sprintf("%s %s:%d: %s\n", label, file, num, msg)
+	} else {
+		line = fmt.Sprintf("%s %s\n", label, msg)
+	}
+
+	l.mu.Lock()
+	_, _ = io.WriteString(l.out, line)
+	l.mu.Unlock()
+}
+
+// formatLabel returns the bracketed level label, e.g. "[DBG]".
+func (l *baseLogger) formatLabel(lvl Level) string {
+	return "[" + lvl.String() + "]"
 }

log/logger_test.go

@@ -6,19 +6,13 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-
-	level2 "github.com/moond4rk/hackbrowserdata/log/level"
-)
-
-const (
-	pattern = `^\[hack\-browser\-data] \w+\.go:\d+:`
 )
 
 type baseTestCase struct {
 	description   string
 	message       string
 	suffix        string
-	level         level2.Level
+	level         Level
 	wantedPattern string
 }
 
@@ -38,13 +32,13 @@ var baseTestCases = []baseTestCase{
 func TestLoggerDebug(t *testing.T) {
 	for _, tc := range baseTestCases {
 		tc := tc
-		tc.level = level2.DebugLevel
+		tc.level = DebugLevel
 		message := tc.message + tc.suffix
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, tc.message)
+		tc.wantedPattern = fmt.Sprintf(`^\[DBG\] \w+\.go:\d+: %s\n$`, tc.message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
-			logger.SetLevel(level2.DebugLevel)
+			logger.SetLevel(DebugLevel)
 			logger.Debug(message)
 			got := buf.String()
 			assert.Regexp(t, tc.wantedPattern, got)
@@ -52,12 +46,28 @@ func TestLoggerDebug(t *testing.T) {
 	}
 }
 
+func TestLoggerInfo(t *testing.T) {
+	for _, tc := range baseTestCases {
+		tc := tc
+		tc.level = InfoLevel
+		message := tc.message + tc.suffix
+		tc.wantedPattern = fmt.Sprintf(`^\[INF\] %s\n$`, tc.message)
+		t.Run(tc.description, func(t *testing.T) {
+			var buf bytes.Buffer
+			logger := NewLogger(newBase(&buf))
+			logger.Info(message)
+			got := buf.String()
+			assert.Regexp(t, tc.wantedPattern, got)
+		})
+	}
+}
+
 func TestLoggerWarn(t *testing.T) {
 	for _, tc := range baseTestCases {
 		tc := tc
-		tc.level = level2.WarnLevel
+		tc.level = WarnLevel
 		message := tc.message + tc.suffix
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, tc.message)
+		tc.wantedPattern = fmt.Sprintf(`^\[WRN\] %s\n$`, tc.message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
@@ -71,9 +81,9 @@ func TestLoggerWarn(t *testing.T) {
 func TestLoggerError(t *testing.T) {
 	for _, tc := range baseTestCases {
 		tc := tc
-		tc.level = level2.ErrorLevel
+		tc.level = ErrorLevel
 		message := tc.message + tc.suffix
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, tc.message)
+		tc.wantedPattern = fmt.Sprintf(`^\[ERR\] %s\n$`, tc.message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
@@ -90,9 +100,9 @@ func TestLoggerFatal(t *testing.T) {
 
 	for _, tc := range baseTestCases {
 		tc := tc
-		tc.level = level2.FatalLevel
+		tc.level = FatalLevel
 		message := tc.message + tc.suffix
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, tc.message)
+		tc.wantedPattern = fmt.Sprintf(`^\[FTL\] %s\n$`, tc.message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			exitCalled := false
@@ -115,23 +125,23 @@ type formatTestCase struct {
 	description   string
 	format        string
 	args          []interface{}
-	level         level2.Level
+	level         Level
 	wantedPattern string
 }
 
 var formatTestCases = []formatTestCase{
 	{
-		description: "message with format prefix",
+		description: "message with string format",
 		format:      "hello, %s!",
 		args:        []any{"Hacker"},
 	},
 	{
-		description: "message with format prefix",
+		description: "message with int format",
 		format:      "hello, %d,%d,%d!",
 		args:        []any{1, 2, 3},
 	},
 	{
-		description: "message with format prefix",
+		description: "message with mixed format",
 		format:      "hello, %s,%d,%d!",
 		args:        []any{"Hacker", 2, 3},
 	},
@@ -140,13 +150,13 @@ var formatTestCases = []formatTestCase{
 func TestLoggerDebugf(t *testing.T) {
 	for _, tc := range formatTestCases {
 		tc := tc
-		tc.level = level2.DebugLevel
+		tc.level = DebugLevel
 		message := fmt.Sprintf(tc.format, tc.args...)
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, message)
+		tc.wantedPattern = fmt.Sprintf(`^\[DBG\] \w+\.go:\d+: %s\n$`, message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
-			logger.SetLevel(level2.DebugLevel)
+			logger.SetLevel(DebugLevel)
 			logger.Debugf(tc.format, tc.args...)
 			got := buf.String()
 			assert.Regexp(t, tc.wantedPattern, got)
@@ -154,12 +164,28 @@ func TestLoggerDebugf(t *testing.T) {
 	}
 }
 
+func TestLoggerInfof(t *testing.T) {
+	for _, tc := range formatTestCases {
+		tc := tc
+		tc.level = InfoLevel
+		message := fmt.Sprintf(tc.format, tc.args...)
+		tc.wantedPattern = fmt.Sprintf(`^\[INF\] %s\n$`, message)
+		t.Run(tc.description, func(t *testing.T) {
+			var buf bytes.Buffer
+			logger := NewLogger(newBase(&buf))
+			logger.Infof(tc.format, tc.args...)
+			got := buf.String()
+			assert.Regexp(t, tc.wantedPattern, got)
+		})
+	}
+}
+
 func TestLoggerWarnf(t *testing.T) {
 	for _, tc := range formatTestCases {
 		tc := tc
-		tc.level = level2.WarnLevel
+		tc.level = WarnLevel
 		message := fmt.Sprintf(tc.format, tc.args...)
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, message)
+		tc.wantedPattern = fmt.Sprintf(`^\[WRN\] %s\n$`, message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
@@ -173,9 +199,9 @@ func TestLoggerWarnf(t *testing.T) {
 func TestLoggerErrorf(t *testing.T) {
 	for _, tc := range formatTestCases {
 		tc := tc
-		tc.level = level2.ErrorLevel
+		tc.level = ErrorLevel
 		message := fmt.Sprintf(tc.format, tc.args...)
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, message)
+		tc.wantedPattern = fmt.Sprintf(`^\[ERR\] %s\n$`, message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			logger := NewLogger(newBase(&buf))
@@ -191,9 +217,9 @@ func TestLoggerFatalf(t *testing.T) {
 	defer func() { osExit = originalOsExit }()
 	for _, tc := range formatTestCases {
 		tc := tc
-		tc.level = level2.FatalLevel
+		tc.level = FatalLevel
 		message := fmt.Sprintf(tc.format, tc.args...)
-		tc.wantedPattern = fmt.Sprintf("%s %s: %s\n$", pattern, tc.level, message)
+		tc.wantedPattern = fmt.Sprintf(`^\[FTL\] %s\n$`, message)
 		t.Run(tc.description, func(t *testing.T) {
 			var buf bytes.Buffer
 			exitCalled := false
@@ -213,19 +239,20 @@ func TestLoggerFatalf(t *testing.T) {
 }
 
 func TestLoggerWithLowerLevels(t *testing.T) {
-	// Logger should not log messages at a level
-	// lower than the specified level.
-	levels := []level2.Level{level2.DebugLevel, level2.WarnLevel, level2.ErrorLevel, level2.FatalLevel}
+	originalOsExit := osExit
+	defer func() { osExit = originalOsExit }()
+
+	levels := []Level{DebugLevel, InfoLevel, WarnLevel, ErrorLevel, FatalLevel}
 	ops := []struct {
-		op       string
-		level    level2.Level
-		logFunc  func(*Logger)
-		expected bool
+		op      string
+		level   Level
+		logFunc func(*Logger)
 	}{
-		{"Debug", level2.DebugLevel, func(l *Logger) { l.Debug("hello") }, false},
-		{"Warn", level2.WarnLevel, func(l *Logger) { l.Warn("hello") }, false},
-		{"Error", level2.ErrorLevel, func(l *Logger) { l.Error("hello") }, false},
-		{"Fatal", level2.FatalLevel, func(l *Logger) { l.Fatal("hello") }, false},
+		{"Debug", DebugLevel, func(l *Logger) { l.Debug("hello") }},
+		{"Info", InfoLevel, func(l *Logger) { l.Info("hello") }},
+		{"Warn", WarnLevel, func(l *Logger) { l.Warn("hello") }},
+		{"Error", ErrorLevel, func(l *Logger) { l.Error("hello") }},
+		{"Fatal", FatalLevel, func(l *Logger) { l.Fatal("hello") }},
 	}
 
 	for _, setLevel := range levels {
@@ -236,23 +263,57 @@ func TestLoggerWithLowerLevels(t *testing.T) {
 
 			expectedOutput := op.level >= setLevel
 			exitCalled := false
-			exitCode := 0
 			osExit = func(code int) {
 				exitCalled = true
-				exitCode = code
 			}
 			op.logFunc(logger)
 
 			output := buf.String()
 			if expectedOutput {
-				assert.NotEmpty(t, output)
+				assert.NotEmpty(t, output, "setLevel=%s op=%s should produce output", setLevel, op.op)
 			} else {
-				assert.Empty(t, output)
+				assert.Empty(t, output, "setLevel=%s op=%s should be suppressed", setLevel, op.op)
 			}
-			if op.op == "Fatal" {
-				assert.True(t, exitCalled)
-				assert.Equal(t, 1, exitCode)
+			if op.op == "Fatal" && expectedOutput {
+				assert.True(t, exitCalled, "Fatal should call osExit")
 			}
 		}
 	}
 }
+
+func TestDefaultLevelIsInfo(t *testing.T) {
+	var buf bytes.Buffer
+	logger := NewLogger(newBase(&buf))
+
+	// Debug should be suppressed at default level (InfoLevel).
+	logger.Debug("debug msg")
+	assert.Empty(t, buf.String(), "Debug should be suppressed at default InfoLevel")
+
+	// Info should be visible at default level.
+	logger.Info("info msg")
+	assert.Contains(t, buf.String(), "info msg")
+}
+
+func TestDebugIncludesFileLine(t *testing.T) {
+	var buf bytes.Buffer
+	logger := NewLogger(newBase(&buf))
+	logger.SetLevel(DebugLevel)
+	logger.Debug("test location")
+	got := buf.String()
+	assert.Regexp(t, `^\[DBG\] logger_test\.go:\d+: test location\n$`, got)
+}
+
+func TestInfoHasLabel(t *testing.T) {
+	var buf bytes.Buffer
+	logger := NewLogger(newBase(&buf))
+	logger.Info("clean message")
+	assert.Equal(t, "[INF] clean message\n", buf.String())
+}
+
+func TestMultilineMessageIndented(t *testing.T) {
+	var buf bytes.Buffer
+	logger := NewLogger(newBase(&buf))
+	logger.Warn("line1\nline2\nline3")
+	got := buf.String()
+	assert.Equal(t, "[WRN] line1\n      line2\n      line3\n", got)
+}

output/output.go

@@ -60,11 +60,20 @@ func (o *Writer) Write() error {
 	if err := os.MkdirAll(o.dir, 0o750); err != nil {
 		return fmt.Errorf("create output dir: %w", err)
 	}
-	for _, cs := range o.aggregate() {
+	agg := o.aggregate()
+	for _, cs := range agg {
 		if err := o.writeFile(cs.name, cs.rows); err != nil {
 			return err
 		}
 	}
+	if len(agg) > 0 {
+		fmt.Fprintln(os.Stderr)
+		log.Infof("Exported to %s/", o.dir)
+		for _, cs := range agg {
+			filename := fmt.Sprintf("%s.%s", cs.name, o.formatter.ext())
+			log.Infof("  %-24s %d entries", filename, len(cs.rows))
+		}
+	}
 	return nil
 }
 
@@ -155,6 +164,5 @@ func (o *Writer) writeFile(category string, rows []row) (err error) {
 	if _, err := f.Write(buf.Bytes()); err != nil {
 		return fmt.Errorf("write %s: %w", filename, err)
 	}
-	log.Warnf("export: %s", path)
 	return nil
 }