first-commit

modules/log/color.go

@@ -0,0 +1,121 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+	"strconv"
+)
+
+const escape = "\033"
+
+// ColorAttribute defines a single SGR Code
+type ColorAttribute int
+
+// Base ColorAttributes
+const (
+	Reset ColorAttribute = iota
+	Bold
+	Faint
+	Italic
+	Underline
+	BlinkSlow
+	BlinkRapid
+	ReverseVideo
+	Concealed
+	CrossedOut
+)
+
+// Foreground text colors
+const (
+	FgBlack ColorAttribute = iota + 30
+	FgRed
+	FgGreen
+	FgYellow
+	FgBlue
+	FgMagenta
+	FgCyan
+	FgWhite
+)
+
+// Foreground Hi-Intensity text colors
+const (
+	FgHiBlack ColorAttribute = iota + 90
+	FgHiRed
+	FgHiGreen
+	FgHiYellow
+	FgHiBlue
+	FgHiMagenta
+	FgHiCyan
+	FgHiWhite
+)
+
+// Background text colors
+const (
+	BgBlack ColorAttribute = iota + 40
+	BgRed
+	BgGreen
+	BgYellow
+	BgBlue
+	BgMagenta
+	BgCyan
+	BgWhite
+)
+
+// Background Hi-Intensity text colors
+const (
+	BgHiBlack ColorAttribute = iota + 100
+	BgHiRed
+	BgHiGreen
+	BgHiYellow
+	BgHiBlue
+	BgHiMagenta
+	BgHiCyan
+	BgHiWhite
+)
+
+var (
+	resetBytes   = ColorBytes(Reset)
+	fgCyanBytes  = ColorBytes(FgCyan)
+	fgGreenBytes = ColorBytes(FgGreen)
+)
+
+type ColoredValue struct {
+	v      any
+	colors []ColorAttribute
+}
+
+var _ fmt.Formatter = (*ColoredValue)(nil)
+
+func (c *ColoredValue) Format(f fmt.State, verb rune) {
+	_, _ = f.Write(ColorBytes(c.colors...))
+	s := fmt.Sprintf(fmt.FormatString(f, verb), c.v)
+	_, _ = f.Write([]byte(s))
+	_, _ = f.Write(resetBytes)
+}
+
+func (c *ColoredValue) Value() any {
+	return c.v
+}
+
+func NewColoredValue(v any, color ...ColorAttribute) *ColoredValue {
+	return &ColoredValue{v: v, colors: color}
+}
+
+// ColorBytes converts a list of ColorAttributes to a byte array
+func ColorBytes(attrs ...ColorAttribute) []byte {
+	bytes := make([]byte, 0, 20)
+	bytes = append(bytes, escape[0], '[')
+	if len(attrs) > 0 {
+		bytes = append(bytes, strconv.Itoa(int(attrs[0]))...)
+		for _, a := range attrs[1:] {
+			bytes = append(bytes, ';')
+			bytes = append(bytes, strconv.Itoa(int(a))...)
+		}
+	} else {
+		bytes = append(bytes, strconv.Itoa(int(Bold))...)
+	}
+	bytes = append(bytes, 'm')
+	return bytes
+}

modules/log/color_console.go

@@ -0,0 +1,14 @@
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+// CanColorStdout reports if we can color the Stdout
+// Although we could do terminal sniffing and the like - in reality
+// most tools on *nix are happy to display ansi colors.
+// We will terminal sniff on Windows in console_windows.go
+var CanColorStdout = true
+
+// CanColorStderr reports if we can color the Stderr
+var CanColorStderr = true

modules/log/color_console_other.go

@@ -0,0 +1,20 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build !windows
+
+package log
+
+import (
+	"os"
+
+	"github.com/mattn/go-isatty"
+)
+
+func init() {
+	// when running gitea as a systemd unit with logging set to console, the output can not be colorized,
+	// otherwise it spams the journal / syslog with escape sequences like "#033[0m#033[32mcmd/web.go:102:#033[32m"
+	// this file covers non-windows platforms.
+	CanColorStdout = isatty.IsTerminal(os.Stdout.Fd())
+	CanColorStderr = isatty.IsTerminal(os.Stderr.Fd())
+}

modules/log/color_console_windows.go

@@ -0,0 +1,42 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"os"
+
+	"github.com/mattn/go-isatty"
+	"golang.org/x/sys/windows"
+)
+
+func enableVTMode(console windows.Handle) bool {
+	mode := uint32(0)
+	err := windows.GetConsoleMode(console, &mode)
+	if err != nil {
+		return false
+	}
+
+	// EnableVirtualTerminalProcessing is the console mode to allow ANSI code
+	// interpretation on the console. See:
+	// https://docs.microsoft.com/en-us/windows/console/setconsolemode
+	// It only works on Windows 10. Earlier terminals will fail with an err which we will
+	// handle to say don't color
+	mode |= windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING
+	err = windows.SetConsoleMode(console, mode)
+	return err == nil
+}
+
+func init() {
+	if isatty.IsTerminal(os.Stdout.Fd()) {
+		CanColorStdout = enableVTMode(windows.Stdout)
+	} else {
+		CanColorStdout = isatty.IsCygwinTerminal(os.Stderr.Fd())
+	}
+
+	if isatty.IsTerminal(os.Stderr.Fd()) {
+		CanColorStderr = enableVTMode(windows.Stderr)
+	} else {
+		CanColorStderr = isatty.IsCygwinTerminal(os.Stderr.Fd())
+	}
+}

modules/log/color_router.go

@@ -0,0 +1,87 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+	"time"
+)
+
+var statusToColor = map[int][]ColorAttribute{
+	100: {Bold},
+	200: {FgGreen},
+	300: {FgYellow},
+	304: {FgCyan},
+	400: {Bold, FgRed},
+	401: {Bold, FgMagenta},
+	403: {Bold, FgMagenta},
+	500: {Bold, BgRed},
+}
+
+// ColoredStatus adds colors for HTTP status
+func ColoredStatus(status int, s ...string) *ColoredValue {
+	color, ok := statusToColor[status]
+	if !ok {
+		color, ok = statusToColor[(status/100)*100]
+	}
+	if !ok {
+		color = []ColorAttribute{Bold}
+	}
+	if len(s) > 0 {
+		return NewColoredValue(s[0], color...)
+	}
+	return NewColoredValue(status, color...)
+}
+
+var methodToColor = map[string][]ColorAttribute{
+	"GET":    {FgBlue},
+	"POST":   {FgGreen},
+	"DELETE": {FgRed},
+	"PATCH":  {FgCyan},
+	"PUT":    {FgYellow, Faint},
+	"HEAD":   {FgBlue, Faint},
+}
+
+// ColoredMethod adds colors for HTTP methods on log
+func ColoredMethod(method string) *ColoredValue {
+	color, ok := methodToColor[method]
+	if !ok {
+		return NewColoredValue(method, Bold)
+	}
+	return NewColoredValue(method, color...)
+}
+
+var (
+	durations = []time.Duration{
+		10 * time.Millisecond,
+		100 * time.Millisecond,
+		1 * time.Second,
+		5 * time.Second,
+		10 * time.Second,
+	}
+
+	durationColors = [][]ColorAttribute{
+		{FgGreen},
+		{Bold},
+		{FgYellow},
+		{FgRed, Bold},
+		{BgRed},
+	}
+
+	wayTooLong = BgMagenta
+)
+
+// ColoredTime converts the provided time to a ColoredValue for logging. The duration is always formatted in milliseconds.
+func ColoredTime(duration time.Duration) *ColoredValue {
+	// the output of duration in Millisecond is more readable:
+	// * before: "100.1ms" "100.1μs" "100.1s"
+	// * better: "100.1ms" "0.1ms"   "100100.0ms", readers can compare the values at first glance.
+	str := fmt.Sprintf("%.1fms", float64(duration.Microseconds())/1000)
+	for i, k := range durations {
+		if duration < k {
+			return NewColoredValue(str, durationColors[i]...)
+		}
+	}
+	return NewColoredValue(str, wayTooLong)
+}

modules/log/event_format.go

@@ -0,0 +1,255 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"time"
+)
+
+type Event struct {
+	Time time.Time
+
+	Caller   string
+	Filename string
+	Line     int
+
+	Level Level
+
+	MsgSimpleText string
+
+	msgFormat string // the format and args is only valid in the caller's goroutine
+	msgArgs   []any  // they are discarded before the event is passed to the writer's channel
+
+	Stacktrace string
+}
+
+type EventFormatted struct {
+	Origin *Event
+	Msg    any // the message formatted by the writer's formatter, the writer knows its type
+}
+
+type EventFormatter func(mode *WriterMode, event *Event, msgFormat string, msgArgs ...any) []byte
+
+type logStringFormatter struct {
+	v LogStringer
+}
+
+var _ fmt.Formatter = logStringFormatter{}
+
+func (l logStringFormatter) Format(f fmt.State, verb rune) {
+	if f.Flag('#') && verb == 'v' {
+		_, _ = fmt.Fprintf(f, "%#v", l.v)
+		return
+	}
+	_, _ = f.Write([]byte(l.v.LogString()))
+}
+
+// Copy of cheap integer to fixed-width decimal to ascii from logger.
+// TODO: legacy bugs: doesn't support negative number, overflow if wid it too large.
+func itoa(buf []byte, i, wid int) []byte {
+	var s [20]byte
+	bp := len(s) - 1
+	for i >= 10 || wid > 1 {
+		wid--
+		q := i / 10
+		s[bp] = byte('0' + i - q*10)
+		bp--
+		i = q
+	}
+	// i < 10
+	s[bp] = byte('0' + i)
+	return append(buf, s[bp:]...)
+}
+
+func colorSprintf(colorize bool, format string, args ...any) string {
+	hasColorValue := false
+	for _, v := range args {
+		if _, hasColorValue = v.(*ColoredValue); hasColorValue {
+			break
+		}
+	}
+	if colorize || !hasColorValue {
+		return fmt.Sprintf(format, args...)
+	}
+
+	noColors := make([]any, len(args))
+	copy(noColors, args)
+	for i, v := range args {
+		if cv, ok := v.(*ColoredValue); ok {
+			noColors[i] = cv.v
+		}
+	}
+	return fmt.Sprintf(format, noColors...)
+}
+
+// EventFormatTextMessage makes the log message for a writer with its mode. This function is a copy of the original package
+func EventFormatTextMessage(mode *WriterMode, event *Event, msgFormat string, msgArgs ...any) []byte {
+	buf := make([]byte, 0, 1024)
+	buf = append(buf, mode.Prefix...)
+	t := event.Time
+	flags := mode.Flags.Bits()
+	if flags&(Ldate|Ltime|Lmicroseconds) != 0 {
+		if mode.Colorize {
+			buf = append(buf, fgCyanBytes...)
+		}
+		if flags&LUTC != 0 {
+			t = t.UTC()
+		}
+		if flags&Ldate != 0 {
+			year, month, day := t.Date()
+			buf = itoa(buf, year, 4)
+			buf = append(buf, '/')
+			buf = itoa(buf, int(month), 2)
+			buf = append(buf, '/')
+			buf = itoa(buf, day, 2)
+			buf = append(buf, ' ')
+		}
+		if flags&(Ltime|Lmicroseconds) != 0 {
+			hour, minNum, sec := t.Clock()
+			buf = itoa(buf, hour, 2)
+			buf = append(buf, ':')
+			buf = itoa(buf, minNum, 2)
+			buf = append(buf, ':')
+			buf = itoa(buf, sec, 2)
+			if flags&Lmicroseconds != 0 {
+				buf = append(buf, '.')
+				buf = itoa(buf, t.Nanosecond()/1e3, 6)
+			}
+			buf = append(buf, ' ')
+		}
+		if mode.Colorize {
+			buf = append(buf, resetBytes...)
+		}
+	}
+	if flags&(Lshortfile|Llongfile) != 0 && event.Filename != "" {
+		if mode.Colorize {
+			buf = append(buf, fgGreenBytes...)
+		}
+		file := event.Filename
+		if flags&Lmedfile == Lmedfile {
+			fileLen := len(file)
+			const softLimit = 20
+			if fileLen > softLimit {
+				slashIndex := strings.LastIndexByte(file[:fileLen-softLimit], '/')
+				if slashIndex != -1 {
+					file = ".../" + file[slashIndex+1:]
+				}
+			}
+		} else if flags&Lshortfile != 0 {
+			startIndex := strings.LastIndexByte(file, '/')
+			if startIndex > 0 && startIndex < len(file) {
+				file = file[startIndex+1:]
+			}
+		}
+		buf = append(buf, file...)
+		buf = append(buf, ':')
+		buf = itoa(buf, event.Line, -1)
+		if flags&(Lfuncname|Lshortfuncname) != 0 {
+			buf = append(buf, ':')
+		} else {
+			if mode.Colorize {
+				buf = append(buf, resetBytes...)
+			}
+			buf = append(buf, ' ')
+		}
+	}
+	if flags&(Lfuncname|Lshortfuncname) != 0 {
+		if mode.Colorize {
+			buf = append(buf, fgGreenBytes...)
+		}
+		funcName := event.Caller
+		shortFuncName := funcName
+		if flags&Lshortfuncname != 0 {
+			// funcName = "code.gitea.io/gitea/modules/foo/bar.MyFunc.func1.2()"
+			slashPos := strings.LastIndexByte(funcName, '/')
+			dotPos := strings.IndexByte(funcName[slashPos+1:], '.')
+			if dotPos > 0 {
+				// shortFuncName = "MyFunc.func1.2()"
+				shortFuncName = funcName[slashPos+1+dotPos+1:]
+				if strings.Contains(shortFuncName, ".") {
+					shortFuncName = strings.ReplaceAll(shortFuncName, ".func", ".")
+				}
+			}
+			funcName = shortFuncName
+		}
+		buf = append(buf, funcName...)
+		if mode.Colorize {
+			buf = append(buf, resetBytes...)
+		}
+		buf = append(buf, ' ')
+	}
+
+	if flags&(Llevel|Llevelinitial) != 0 {
+		level := strings.ToUpper(event.Level.String())
+		if mode.Colorize {
+			buf = append(buf, ColorBytes(levelToColor[event.Level]...)...)
+		}
+		buf = append(buf, '[')
+		if flags&Llevelinitial != 0 {
+			buf = append(buf, level[0])
+		} else {
+			buf = append(buf, level...)
+		}
+		buf = append(buf, ']')
+		if mode.Colorize {
+			buf = append(buf, resetBytes...)
+		}
+		buf = append(buf, ' ')
+	}
+
+	var msg []byte
+
+	// if the log needs colorizing, do it
+	if mode.Colorize && len(msgArgs) > 0 {
+		hasColorValue := false
+		for _, v := range msgArgs {
+			if _, hasColorValue = v.(*ColoredValue); hasColorValue {
+				break
+			}
+		}
+		if hasColorValue {
+			msg = fmt.Appendf(nil, msgFormat, msgArgs...)
+		}
+	}
+	// try to re-use the pre-formatted simple text message
+	if len(msg) == 0 {
+		msg = []byte(event.MsgSimpleText)
+	}
+	// if still no message, do the normal Sprintf for the message
+	if len(msg) == 0 {
+		msg = []byte(colorSprintf(mode.Colorize, msgFormat, msgArgs...))
+	}
+	// remove at most one trailing new line
+	if len(msg) > 0 && msg[len(msg)-1] == '\n' {
+		msg = msg[:len(msg)-1]
+	}
+
+	if flags&Lgopid == Lgopid {
+		deprecatedGoroutinePid := "no-gopid" // use a dummy value to avoid breaking the log format
+		buf = append(buf, '[')
+		if mode.Colorize {
+			buf = append(buf, ColorBytes(FgHiYellow)...)
+		}
+		buf = append(buf, deprecatedGoroutinePid...)
+		if mode.Colorize {
+			buf = append(buf, resetBytes...)
+		}
+		buf = append(buf, ']', ' ')
+	}
+	buf = append(buf, msg...)
+
+	if event.Stacktrace != "" && mode.StacktraceLevel <= event.Level {
+		lines := bytes.SplitSeq([]byte(event.Stacktrace), []byte("\n"))
+		for line := range lines {
+			buf = append(buf, "\n\t"...)
+			buf = append(buf, line...)
+		}
+		buf = append(buf, '\n')
+	}
+	buf = append(buf, '\n')
+	return buf
+}

modules/log/event_format_test.go

@@ -0,0 +1,55 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestItoa(t *testing.T) {
+	b := itoa(nil, 0, 0)
+	assert.Equal(t, "0", string(b))
+
+	b = itoa(nil, 0, 1)
+	assert.Equal(t, "0", string(b))
+
+	b = itoa(nil, 0, 2)
+	assert.Equal(t, "00", string(b))
+}
+
+func TestEventFormatTextMessage(t *testing.T) {
+	res := EventFormatTextMessage(&WriterMode{Prefix: "[PREFIX] ", Colorize: false, Flags: Flags{defined: true, flags: 0xffffffff}},
+		&Event{
+			Time:       time.Date(2020, 1, 2, 3, 4, 5, 6, time.UTC),
+			Caller:     "caller",
+			Filename:   "filename",
+			Line:       123,
+			Level:      ERROR,
+			Stacktrace: "stacktrace",
+		},
+		"msg format: %v %v", "arg0", NewColoredValue("arg1", FgBlue),
+	)
+
+	assert.Equal(t, `[PREFIX] 2020/01/02 03:04:05.000000 filename:123:caller [E] [no-gopid] msg format: arg0 arg1
+	stacktrace
+
+`, string(res))
+
+	res = EventFormatTextMessage(&WriterMode{Prefix: "[PREFIX] ", Colorize: true, Flags: Flags{defined: true, flags: 0xffffffff}},
+		&Event{
+			Time:       time.Date(2020, 1, 2, 3, 4, 5, 6, time.UTC),
+			Caller:     "caller",
+			Filename:   "filename",
+			Line:       123,
+			Level:      ERROR,
+			Stacktrace: "stacktrace",
+		},
+		"msg format: %v %v", "arg0", NewColoredValue("arg1", FgBlue),
+	)
+
+	assert.Equal(t, "[PREFIX] \x1b[36m2020/01/02 03:04:05.000000 \x1b[0m\x1b[32mfilename:123:\x1b[32mcaller\x1b[0m \x1b[1;31m[E]\x1b[0m [\x1b[93mno-gopid\x1b[0m] msg format: arg0 \x1b[34marg1\x1b[0m\n\tstacktrace\n\n", string(res))
+}

modules/log/event_writer.go

@@ -0,0 +1,54 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+)
+
+// EventWriter is the general interface for all event writers
+// EventWriterBase is only used as its base interface
+// A writer implementation could override the default EventWriterBase functions
+// eg: a writer can override the Run to handle events in its own way with its own goroutine
+type EventWriter interface {
+	EventWriterBase
+}
+
+// WriterMode is the mode for creating a new EventWriter, it contains common options for all writers
+// Its WriterOption field is the specified options for a writer, it should be passed by value but not by pointer
+type WriterMode struct {
+	BufferLen int
+
+	Level    Level
+	Prefix   string
+	Colorize bool
+	Flags    Flags
+
+	Expression string
+
+	StacktraceLevel Level
+
+	WriterOption any
+}
+
+// EventWriterProvider is the function for creating a new EventWriter
+type EventWriterProvider func(writerName string, writerMode WriterMode) EventWriter
+
+var eventWriterProviders = map[string]EventWriterProvider{}
+
+func RegisterEventWriter(writerType string, p EventWriterProvider) {
+	eventWriterProviders[writerType] = p
+}
+
+func HasEventWriter(writerType string) bool {
+	_, ok := eventWriterProviders[writerType]
+	return ok
+}
+
+func NewEventWriter(name, writerType string, mode WriterMode) (EventWriter, error) {
+	if p, ok := eventWriterProviders[writerType]; ok {
+		return p(name, mode), nil
+	}
+	return nil, fmt.Errorf("unknown event writer type %q for writer %q", writerType, name)
+}

modules/log/event_writer_base.go

@@ -0,0 +1,169 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"regexp"
+	"runtime/pprof"
+	"time"
+)
+
+// EventWriterBase is the base interface for most event writers
+// It provides default implementations for most methods
+type EventWriterBase interface {
+	Base() *EventWriterBaseImpl
+	GetWriterType() string
+	GetWriterName() string
+	GetLevel() Level
+
+	Run(ctx context.Context)
+}
+
+type EventWriterBaseImpl struct {
+	writerType string
+
+	Name  string
+	Mode  *WriterMode
+	Queue chan *EventFormatted
+
+	FormatMessage     EventFormatter // format the Event to a message and write it to output
+	OutputWriteCloser io.WriteCloser // it will be closed when the event writer is stopped
+	GetPauseChan      func() chan struct{}
+
+	shared  bool
+	stopped chan struct{}
+}
+
+var _ EventWriterBase = (*EventWriterBaseImpl)(nil)
+
+func (b *EventWriterBaseImpl) Base() *EventWriterBaseImpl {
+	return b
+}
+
+func (b *EventWriterBaseImpl) GetWriterType() string {
+	return b.writerType
+}
+
+func (b *EventWriterBaseImpl) GetWriterName() string {
+	return b.Name
+}
+
+func (b *EventWriterBaseImpl) GetLevel() Level {
+	return b.Mode.Level
+}
+
+// Run is the default implementation for EventWriter.Run
+func (b *EventWriterBaseImpl) Run(ctx context.Context) {
+	defer b.OutputWriteCloser.Close()
+
+	var exprRegexp *regexp.Regexp
+	if b.Mode.Expression != "" {
+		var err error
+		if exprRegexp, err = regexp.Compile(b.Mode.Expression); err != nil {
+			FallbackErrorf("unable to compile expression %q for writer %q: %v", b.Mode.Expression, b.Name, err)
+		}
+	}
+
+	handlePaused := func() {
+		if pause := b.GetPauseChan(); pause != nil {
+			select {
+			case <-pause:
+			case <-ctx.Done():
+			}
+		}
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case event, ok := <-b.Queue:
+			if !ok {
+				return
+			}
+
+			handlePaused()
+
+			if exprRegexp != nil {
+				fileLineCaller := fmt.Sprintf("%s:%d:%s", event.Origin.Filename, event.Origin.Line, event.Origin.Caller)
+				matched := exprRegexp.MatchString(fileLineCaller) || exprRegexp.MatchString(event.Origin.MsgSimpleText)
+				if !matched {
+					continue
+				}
+			}
+
+			var err error
+			switch msg := event.Msg.(type) {
+			case string:
+				_, err = b.OutputWriteCloser.Write([]byte(msg))
+			case []byte:
+				_, err = b.OutputWriteCloser.Write(msg)
+			case io.WriterTo:
+				_, err = msg.WriteTo(b.OutputWriteCloser)
+			default:
+				_, err = fmt.Fprint(b.OutputWriteCloser, msg)
+			}
+			if err != nil {
+				FallbackErrorf("unable to write log message of %q (%v): %v", b.Name, err, event.Msg)
+			}
+		}
+	}
+}
+
+func NewEventWriterBase(name, writerType string, mode WriterMode) *EventWriterBaseImpl {
+	if mode.BufferLen == 0 {
+		mode.BufferLen = 1000
+	}
+	if mode.Level == UNDEFINED {
+		mode.Level = INFO
+	}
+	if mode.StacktraceLevel == UNDEFINED {
+		mode.StacktraceLevel = NONE
+	}
+	b := &EventWriterBaseImpl{
+		writerType: writerType,
+
+		Name:  name,
+		Mode:  &mode,
+		Queue: make(chan *EventFormatted, mode.BufferLen),
+
+		GetPauseChan:  GetManager().GetPauseChan, // by default, use the global pause channel
+		FormatMessage: EventFormatTextMessage,
+	}
+	return b
+}
+
+// eventWriterStartGo use "go" to start an event worker's Run method
+func eventWriterStartGo(ctx context.Context, w EventWriter, shared bool) {
+	if w.Base().stopped != nil {
+		return // already started
+	}
+	w.Base().shared = shared
+	w.Base().stopped = make(chan struct{})
+
+	ctxDesc := "Logger: EventWriter: " + w.GetWriterName()
+	if shared {
+		ctxDesc = "Logger: EventWriter (shared): " + w.GetWriterName()
+	}
+	writerCtx, writerCancel := newProcessTypedContext(ctx, ctxDesc)
+	go func() {
+		defer writerCancel()
+		defer close(w.Base().stopped)
+		pprof.SetGoroutineLabels(writerCtx)
+		w.Run(writerCtx)
+	}()
+}
+
+// eventWriterStopWait stops an event writer and waits for it to finish flushing (with a timeout)
+func eventWriterStopWait(w EventWriter) {
+	close(w.Base().Queue)
+	select {
+	case <-w.Base().stopped:
+	case <-time.After(2 * time.Second):
+		FallbackErrorf("unable to stop log writer %q in time, skip", w.GetWriterName())
+	}
+}

modules/log/event_writer_conn.go

@@ -0,0 +1,111 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"io"
+	"net"
+)
+
+type WriterConnOption struct {
+	Addr           string
+	Protocol       string
+	Reconnect      bool
+	ReconnectOnMsg bool
+}
+
+type eventWriterConn struct {
+	*EventWriterBaseImpl
+	connWriter connWriter
+}
+
+var _ EventWriter = (*eventWriterConn)(nil)
+
+func NewEventWriterConn(writerName string, writerMode WriterMode) EventWriter {
+	w := &eventWriterConn{EventWriterBaseImpl: NewEventWriterBase(writerName, "conn", writerMode)}
+	opt := writerMode.WriterOption.(WriterConnOption)
+	w.connWriter = connWriter{
+		ReconnectOnMsg: opt.ReconnectOnMsg,
+		Reconnect:      opt.Reconnect,
+		Net:            opt.Protocol,
+		Addr:           opt.Addr,
+	}
+	w.OutputWriteCloser = &w.connWriter
+	return w
+}
+
+func init() {
+	RegisterEventWriter("conn", NewEventWriterConn)
+}
+
+// below is copied from old code
+
+type connWriter struct {
+	innerWriter io.WriteCloser
+
+	ReconnectOnMsg bool
+	Reconnect      bool
+	Net            string `json:"net"`
+	Addr           string `json:"addr"`
+}
+
+var _ io.WriteCloser = (*connWriter)(nil)
+
+// Close the inner writer
+func (i *connWriter) Close() error {
+	if i.innerWriter != nil {
+		return i.innerWriter.Close()
+	}
+	return nil
+}
+
+// Write the data to the connection
+func (i *connWriter) Write(p []byte) (int, error) {
+	if i.neededConnectOnMsg() {
+		if err := i.connect(); err != nil {
+			return 0, err
+		}
+	}
+
+	if i.ReconnectOnMsg {
+		defer i.innerWriter.Close()
+	}
+
+	return i.innerWriter.Write(p)
+}
+
+func (i *connWriter) neededConnectOnMsg() bool {
+	if i.Reconnect {
+		i.Reconnect = false
+		return true
+	}
+
+	if i.innerWriter == nil {
+		return true
+	}
+
+	return i.ReconnectOnMsg
+}
+
+func (i *connWriter) connect() error {
+	if i.innerWriter != nil {
+		_ = i.innerWriter.Close()
+		i.innerWriter = nil
+	}
+
+	conn, err := net.Dial(i.Net, i.Addr)
+	if err != nil {
+		return err
+	}
+
+	if tcpConn, ok := conn.(*net.TCPConn); ok {
+		err = tcpConn.SetKeepAlive(true)
+		if err != nil {
+			return err
+		}
+	}
+
+	i.innerWriter = conn
+	return nil
+}

modules/log/event_writer_conn_test.go

@@ -0,0 +1,74 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func listenReadAndClose(t *testing.T, l net.Listener, expected string) {
+	conn, err := l.Accept()
+	assert.NoError(t, err)
+	defer conn.Close()
+	written, err := io.ReadAll(conn)
+
+	assert.NoError(t, err)
+	assert.Equal(t, expected, string(written))
+}
+
+func TestConnLogger(t *testing.T) {
+	protocol := "tcp"
+	address := ":3099"
+
+	l, err := net.Listen(protocol, address)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer l.Close()
+
+	prefix := "TestPrefix "
+	level := INFO
+	flags := LstdFlags | LUTC | Lfuncname
+
+	logger := NewLoggerWithWriters(t.Context(), "test", NewEventWriterConn("test-conn", WriterMode{
+		Level:        level,
+		Prefix:       prefix,
+		Flags:        FlagsFromBits(flags),
+		WriterOption: WriterConnOption{Addr: address, Protocol: protocol, Reconnect: true, ReconnectOnMsg: true},
+	}))
+
+	location, _ := time.LoadLocation("EST")
+
+	date := time.Date(2019, time.January, 13, 22, 3, 30, 15, location)
+
+	dateString := date.UTC().Format("2006/01/02 15:04:05")
+
+	event := Event{
+		Level:         INFO,
+		MsgSimpleText: "TEST MSG",
+		Caller:        "CALLER",
+		Filename:      "FULL/FILENAME",
+		Line:          1,
+		Time:          date,
+	}
+	expected := fmt.Sprintf("%s%s %s:%d:%s [%c] %s\n", prefix, dateString, event.Filename, event.Line, event.Caller, strings.ToUpper(event.Level.String())[0], event.MsgSimpleText)
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		listenReadAndClose(t, l, expected)
+	}()
+	logger.SendLogEvent(&event)
+	wg.Wait()
+
+	logger.Close()
+}

modules/log/event_writer_console.go

@@ -0,0 +1,35 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"os"
+
+	"code.gitea.io/gitea/modules/util"
+)
+
+type WriterConsoleOption struct {
+	Stderr bool
+}
+
+type eventWriterConsole struct {
+	*EventWriterBaseImpl
+}
+
+var _ EventWriter = (*eventWriterConsole)(nil)
+
+func NewEventWriterConsole(name string, mode WriterMode) EventWriter {
+	w := &eventWriterConsole{EventWriterBaseImpl: NewEventWriterBase(name, "console", mode)}
+	opt := mode.WriterOption.(WriterConsoleOption)
+	if opt.Stderr {
+		w.OutputWriteCloser = util.NopCloser{Writer: os.Stderr}
+	} else {
+		w.OutputWriteCloser = util.NopCloser{Writer: os.Stdout}
+	}
+	return w
+}
+
+func init() {
+	RegisterEventWriter("console", NewEventWriterConsole)
+}

modules/log/event_writer_file.go

@@ -0,0 +1,54 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"io"
+
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/util/rotatingfilewriter"
+)
+
+type WriterFileOption struct {
+	FileName         string
+	MaxSize          int64
+	LogRotate        bool
+	DailyRotate      bool
+	MaxDays          int
+	Compress         bool
+	CompressionLevel int
+}
+
+type eventWriterFile struct {
+	*EventWriterBaseImpl
+	fileWriter io.WriteCloser
+}
+
+var _ EventWriter = (*eventWriterFile)(nil)
+
+func NewEventWriterFile(name string, mode WriterMode) EventWriter {
+	w := &eventWriterFile{EventWriterBaseImpl: NewEventWriterBase(name, "file", mode)}
+	opt := mode.WriterOption.(WriterFileOption)
+	var err error
+	w.fileWriter, err = rotatingfilewriter.Open(opt.FileName, &rotatingfilewriter.Options{
+		Rotate:           opt.LogRotate,
+		MaximumSize:      opt.MaxSize,
+		RotateDaily:      opt.DailyRotate,
+		KeepDays:         opt.MaxDays,
+		Compress:         opt.Compress,
+		CompressionLevel: opt.CompressionLevel,
+	})
+	if err != nil {
+		// if the log file can't be opened, what should it do? panic/exit? ignore logs? fallback to stderr?
+		// it seems that "fallback to stderr" is slightly better than others ....
+		FallbackErrorf("unable to open log file %q: %v", opt.FileName, err)
+		w.fileWriter = util.NopCloser{Writer: LoggerToWriter(FallbackErrorf)}
+	}
+	w.OutputWriteCloser = w.fileWriter
+	return w
+}
+
+func init() {
+	RegisterEventWriter("file", NewEventWriterFile)
+}

modules/log/flags.go

@@ -0,0 +1,134 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"sort"
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+)
+
+// These flags define which text to prefix to each log entry generated
+// by the Logger. Bits are or'ed together to control what's printed.
+// There is no control over the order they appear (the order listed
+// here) or the format they present (as described in the comments).
+// The prefix is followed by a colon only if more than time is stated
+// is specified. For example, flags Ldate | Ltime
+// produce, 2009/01/23 01:23:23 message.
+// The standard is:
+// 2009/01/23 01:23:23 ...a/logger/c/d.go:23:runtime.Caller() [I]: message
+const (
+	Ldate          uint32 = 1 << iota // the date in the local time zone: 2009/01/23
+	Ltime                             // the time in the local time zone: 01:23:23
+	Lmicroseconds                     // microsecond resolution: 01:23:23.123123.  assumes Ltime.
+	Llongfile                         // full file name and line number: /a/logger/c/d.go:23
+	Lshortfile                        // final file name element and line number: d.go:23. overrides Llongfile
+	Lfuncname                         // function name of the caller: runtime.Caller()
+	Lshortfuncname                    // last part of the function name
+	LUTC                              // if Ldate or Ltime is set, use UTC rather than the local time zone
+	Llevelinitial                     // Initial character of the provided level in brackets, eg. [I] for info
+	Llevel                            // Provided level in brackets [INFO]
+	Lgopid                            // the Goroutine-PID of the context, deprecated and it is always a const value
+
+	Lmedfile  = Lshortfile | Llongfile                                    // last 20 characters of the filename
+	LstdFlags = Ldate | Ltime | Lmedfile | Lshortfuncname | Llevelinitial // default
+)
+
+const Ldefault = LstdFlags
+
+type Flags struct {
+	defined bool
+	flags   uint32
+}
+
+var flagFromString = map[string]uint32{
+	"date":          Ldate,
+	"time":          Ltime,
+	"microseconds":  Lmicroseconds,
+	"longfile":      Llongfile,
+	"shortfile":     Lshortfile,
+	"funcname":      Lfuncname,
+	"shortfuncname": Lshortfuncname,
+	"utc":           LUTC,
+	"levelinitial":  Llevelinitial,
+	"level":         Llevel,
+	"gopid":         Lgopid,
+
+	"medfile":  Lmedfile,
+	"stdflags": LstdFlags,
+}
+
+var flagComboToString = []struct {
+	flag uint32
+	name string
+}{
+	// name with more bits comes first
+	{LstdFlags, "stdflags"},
+	{Lmedfile, "medfile"},
+
+	{Ldate, "date"},
+	{Ltime, "time"},
+	{Lmicroseconds, "microseconds"},
+	{Llongfile, "longfile"},
+	{Lshortfile, "shortfile"},
+	{Lfuncname, "funcname"},
+	{Lshortfuncname, "shortfuncname"},
+	{LUTC, "utc"},
+	{Llevelinitial, "levelinitial"},
+	{Llevel, "level"},
+	{Lgopid, "gopid"},
+}
+
+func (f Flags) Bits() uint32 {
+	if !f.defined {
+		return Ldefault
+	}
+	return f.flags
+}
+
+func (f Flags) String() string {
+	flags := f.Bits()
+	var flagNames []string
+	for _, it := range flagComboToString {
+		if flags&it.flag == it.flag {
+			flags &^= it.flag
+			flagNames = append(flagNames, it.name)
+		}
+	}
+	if len(flagNames) == 0 {
+		return "none"
+	}
+	sort.Strings(flagNames)
+	return strings.Join(flagNames, ",")
+}
+
+func (f *Flags) UnmarshalJSON(bytes []byte) error {
+	var s string
+	if err := json.Unmarshal(bytes, &s); err != nil {
+		return err
+	}
+	*f = FlagsFromString(s)
+	return nil
+}
+
+func (f Flags) MarshalJSON() ([]byte, error) {
+	return []byte(`"` + f.String() + `"`), nil
+}
+
+func FlagsFromString(from string, def ...uint32) Flags {
+	from = strings.TrimSpace(from)
+	if from == "" && len(def) > 0 {
+		return Flags{defined: true, flags: def[0]}
+	}
+	flags := uint32(0)
+	for flag := range strings.SplitSeq(strings.ToLower(from), ",") {
+		flags |= flagFromString[strings.TrimSpace(flag)]
+	}
+	return Flags{defined: true, flags: flags}
+}
+
+func FlagsFromBits(flags uint32) Flags {
+	return Flags{defined: true, flags: flags}
+}

modules/log/flags_test.go

@@ -0,0 +1,30 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/json"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFlags(t *testing.T) {
+	assert.Equal(t, Ldefault, Flags{}.Bits())
+	assert.EqualValues(t, 0, FlagsFromString("").Bits())
+	assert.Equal(t, Lgopid, FlagsFromString("", Lgopid).Bits())
+	assert.EqualValues(t, 0, FlagsFromString("none", Lgopid).Bits())
+	assert.Equal(t, Ldate|Ltime, FlagsFromString("date,time", Lgopid).Bits())
+
+	assert.Equal(t, "stdflags", FlagsFromString("stdflags").String())
+	assert.Equal(t, "medfile", FlagsFromString("medfile").String())
+
+	bs, err := json.Marshal(FlagsFromString("utc,level"))
+	assert.NoError(t, err)
+	assert.Equal(t, `"level,utc"`, string(bs))
+	var flags Flags
+	assert.NoError(t, json.Unmarshal(bs, &flags))
+	assert.Equal(t, LUTC|Llevel, flags.Bits())
+}

modules/log/init.go

@@ -0,0 +1,44 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"context"
+	"runtime"
+	"strings"
+
+	"code.gitea.io/gitea/modules/process"
+	"code.gitea.io/gitea/modules/util/rotatingfilewriter"
+)
+
+var projectPackagePrefix string
+
+func init() {
+	_, filename, _, _ := runtime.Caller(0)
+	projectPackagePrefix = strings.TrimSuffix(filename, "modules/log/init.go")
+	if projectPackagePrefix == filename {
+		// in case the source code file is moved, we can not trim the suffix, the code above should also be updated.
+		panic("unable to detect correct package prefix, please update file: " + filename)
+	}
+
+	rotatingfilewriter.ErrorPrintf = FallbackErrorf
+
+	process.TraceCallback = func(skip int, start bool, pid process.IDType, description string, parentPID process.IDType, typ string) {
+		if start && parentPID != "" {
+			Log(skip+1, TRACE, "Start %s: %s (from %s) (%s)", NewColoredValue(pid, FgHiYellow), description, NewColoredValue(parentPID, FgYellow), NewColoredValue(typ, Reset))
+		} else if start {
+			Log(skip+1, TRACE, "Start %s: %s (%s)", NewColoredValue(pid, FgHiYellow), description, NewColoredValue(typ, Reset))
+		} else {
+			Log(skip+1, TRACE, "Done %s: %s", NewColoredValue(pid, FgHiYellow), NewColoredValue(description, Reset))
+		}
+	}
+}
+
+func newProcessTypedContext(parent context.Context, desc string) (ctx context.Context, cancel context.CancelFunc) {
+	// the "process manager" also calls "log.Trace()" to output logs, so if we want to create new contexts by the manager, we need to disable the trace temporarily
+	process.TraceLogDisable(true)
+	defer process.TraceLogDisable(false)
+	ctx, _, cancel = process.GetManager().AddTypedContext(parent, desc, process.SystemProcessType, false)
+	return ctx, cancel
+}

modules/log/level.go

@@ -0,0 +1,116 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"bytes"
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+)
+
+// Level is the level of the logger
+type Level int
+
+const (
+	UNDEFINED Level = iota
+	TRACE
+	DEBUG
+	INFO
+	WARN
+	ERROR
+	FATAL
+	NONE
+)
+
+const CRITICAL = ERROR // most logger frameworks doesn't support CRITICAL, and it doesn't seem useful
+
+var toString = map[Level]string{
+	UNDEFINED: "undefined",
+
+	TRACE: "trace",
+	DEBUG: "debug",
+	INFO:  "info",
+	WARN:  "warn",
+	ERROR: "error",
+
+	FATAL: "fatal",
+	NONE:  "none",
+}
+
+var toLevel = map[string]Level{
+	"undefined": UNDEFINED,
+
+	"trace":   TRACE,
+	"debug":   DEBUG,
+	"info":    INFO,
+	"warn":    WARN,
+	"warning": WARN,
+	"error":   ERROR,
+
+	"fatal": FATAL,
+	"none":  NONE,
+}
+
+var levelToColor = map[Level][]ColorAttribute{
+	TRACE: {Bold, FgCyan},
+	DEBUG: {Bold, FgBlue},
+	INFO:  {Bold, FgGreen},
+	WARN:  {Bold, FgYellow},
+	ERROR: {Bold, FgRed},
+	FATAL: {Bold, BgRed},
+	NONE:  {Reset},
+}
+
+func (l Level) String() string {
+	s, ok := toString[l]
+	if ok {
+		return s
+	}
+	return "info"
+}
+
+func (l Level) ColorAttributes() []ColorAttribute {
+	color, ok := levelToColor[l]
+	if ok {
+		return color
+	}
+	none := levelToColor[NONE]
+	return none
+}
+
+// MarshalJSON takes a Level and turns it into text
+func (l Level) MarshalJSON() ([]byte, error) {
+	buffer := bytes.NewBufferString(`"`)
+	buffer.WriteString(toString[l])
+	buffer.WriteString(`"`)
+	return buffer.Bytes(), nil
+}
+
+// UnmarshalJSON takes text and turns it into a Level
+func (l *Level) UnmarshalJSON(b []byte) error {
+	var tmp any
+	err := json.Unmarshal(b, &tmp)
+	if err != nil {
+		return err
+	}
+
+	switch v := tmp.(type) {
+	case string:
+		*l = LevelFromString(v)
+	case int:
+		*l = LevelFromString(Level(v).String())
+	default:
+		*l = INFO
+	}
+	return nil
+}
+
+// LevelFromString takes a level string and returns a Level
+func LevelFromString(level string) Level {
+	if l, ok := toLevel[strings.ToLower(level)]; ok {
+		return l
+	}
+	return INFO
+}

modules/log/level_test.go

@@ -0,0 +1,55 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+	"testing"
+
+	"code.gitea.io/gitea/modules/json"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type testLevel struct {
+	Level Level `json:"level"`
+}
+
+func TestLevelMarshalUnmarshalJSON(t *testing.T) {
+	levelBytes, err := json.Marshal(testLevel{
+		Level: INFO,
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, string(makeTestLevelBytes(INFO.String())), string(levelBytes))
+
+	var testLevel testLevel
+	err = json.Unmarshal(levelBytes, &testLevel)
+	assert.NoError(t, err)
+	assert.Equal(t, INFO, testLevel.Level)
+
+	err = json.Unmarshal(makeTestLevelBytes(`FOFOO`), &testLevel)
+	assert.NoError(t, err)
+	assert.Equal(t, INFO, testLevel.Level)
+
+	err = json.Unmarshal(fmt.Appendf(nil, `{"level":%d}`, 2), &testLevel)
+	assert.NoError(t, err)
+	assert.Equal(t, INFO, testLevel.Level)
+
+	err = json.Unmarshal(fmt.Appendf(nil, `{"level":%d}`, 10012), &testLevel)
+	assert.NoError(t, err)
+	assert.Equal(t, INFO, testLevel.Level)
+
+	err = json.Unmarshal([]byte(`{"level":{}}`), &testLevel)
+	assert.NoError(t, err)
+	assert.Equal(t, INFO, testLevel.Level)
+
+	assert.Equal(t, INFO.String(), Level(1001).String())
+
+	err = json.Unmarshal([]byte(`{"level":{}`), &testLevel.Level)
+	assert.Error(t, err)
+}
+
+func makeTestLevelBytes(level string) []byte {
+	return fmt.Appendf(nil, `{"level":"%s"}`, level)
+}

modules/log/logger.go

@@ -0,0 +1,50 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+// Package log provides logging capabilities for Gitea.
+// Concepts:
+//
+// * Logger: a Logger provides logging functions and dispatches log events to all its writers
+//
+// * EventWriter: written log Event to a destination (eg: file, console)
+//   - EventWriterBase: the base struct of a writer, it contains common fields and functions for all writers
+//   - WriterType: the type name of a writer, eg: console, file
+//   - WriterName: aka Mode Name in document, the name of a writer instance, it's usually defined by the config file.
+//     It is called "mode name" because old code use MODE as config key, to keep compatibility, keep this concept.
+//
+// * WriterMode: the common options for all writers, eg: log level.
+//   - WriterConsoleOption and others: the specified options for a writer, eg: file path, remote address.
+//
+// Call graph:
+// -> log.Info()
+// -> LoggerImpl.Log()
+// -> LoggerImpl.SendLogEvent, then the event goes into writer's goroutines
+// -> EventWriter.Run() handles the events
+package log
+
+// BaseLogger provides the basic logging functions
+type BaseLogger interface {
+	Log(skip int, event *Event, format string, v ...any)
+	GetLevel() Level
+}
+
+// LevelLogger provides level-related logging functions
+type LevelLogger interface {
+	LevelEnabled(level Level) bool
+
+	Trace(format string, v ...any)
+	Debug(format string, v ...any)
+	Info(format string, v ...any)
+	Warn(format string, v ...any)
+	Error(format string, v ...any)
+	Critical(format string, v ...any)
+}
+
+type Logger interface {
+	BaseLogger
+	LevelLogger
+}
+
+type LogStringer interface { //nolint:revive // export stutter
+	LogString() string
+}

modules/log/logger_global.go

@@ -0,0 +1,85 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"fmt"
+	"os"
+)
+
+// FallbackErrorf is the last chance to show an error if the logger has internal errors
+func FallbackErrorf(format string, args ...any) {
+	_, _ = fmt.Fprintf(os.Stderr, format+"\n", args...)
+}
+
+func GetLevel() Level {
+	return GetLogger(DEFAULT).GetLevel()
+}
+
+func Log(skip int, level Level, format string, v ...any) {
+	GetLogger(DEFAULT).Log(skip+1, &Event{Level: level}, format, v...)
+}
+
+func Trace(format string, v ...any) {
+	Log(1, TRACE, format, v...)
+}
+
+func IsTrace() bool {
+	return GetLevel() <= TRACE
+}
+
+func Debug(format string, v ...any) {
+	Log(1, DEBUG, format, v...)
+}
+
+func IsDebug() bool {
+	return GetLevel() <= DEBUG
+}
+
+func Info(format string, v ...any) {
+	Log(1, INFO, format, v...)
+}
+
+func Warn(format string, v ...any) {
+	Log(1, WARN, format, v...)
+}
+
+func Error(format string, v ...any) {
+	Log(1, ERROR, format, v...)
+}
+
+func ErrorWithSkip(skip int, format string, v ...any) {
+	Log(skip+1, ERROR, format, v...)
+}
+
+func Critical(format string, v ...any) {
+	Log(1, ERROR, format, v...)
+}
+
+var OsExiter = os.Exit
+
+// Fatal records fatal log and exit process
+func Fatal(format string, v ...any) {
+	Log(1, FATAL, format, v...)
+	GetManager().Close()
+	OsExiter(1)
+}
+
+func GetLogger(name string) Logger {
+	return GetManager().GetLogger(name)
+}
+
+func IsLoggerEnabled(name string) bool {
+	return GetManager().GetLogger(name).IsEnabled()
+}
+
+func SetConsoleLogger(loggerName, writerName string, level Level) {
+	writer := NewEventWriterConsole(writerName, WriterMode{
+		Level:        level,
+		Flags:        FlagsFromBits(LstdFlags),
+		Colorize:     CanColorStdout,
+		WriterOption: WriterConsoleOption{},
+	})
+	GetManager().GetLogger(loggerName).ReplaceAllWriters(writer)
+}

modules/log/logger_impl.go

@@ -0,0 +1,249 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"context"
+	"reflect"
+	"runtime"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/util"
+)
+
+type LoggerImpl struct {
+	LevelLogger
+
+	ctx       context.Context
+	ctxCancel context.CancelFunc
+
+	level           atomic.Int32
+	stacktraceLevel atomic.Int32
+
+	eventWriterMu sync.RWMutex
+	eventWriters  map[string]EventWriter
+}
+
+var (
+	_ BaseLogger  = (*LoggerImpl)(nil)
+	_ LevelLogger = (*LoggerImpl)(nil)
+)
+
+// SendLogEvent sends a log event to all writers
+func (l *LoggerImpl) SendLogEvent(event *Event) {
+	l.eventWriterMu.RLock()
+	defer l.eventWriterMu.RUnlock()
+
+	if len(l.eventWriters) == 0 {
+		FallbackErrorf("[no logger writer]: %s", event.MsgSimpleText)
+		return
+	}
+
+	// the writers have their own goroutines, the message arguments (with Stringer) shouldn't be used in other goroutines
+	// so the event message must be formatted here
+	msgFormat, msgArgs := event.msgFormat, event.msgArgs
+	event.msgFormat, event.msgArgs = "(already processed by formatters)", nil
+
+	for _, w := range l.eventWriters {
+		if event.Level < w.GetLevel() {
+			continue
+		}
+		formatted := &EventFormatted{
+			Origin: event,
+			Msg:    w.Base().FormatMessage(w.Base().Mode, event, msgFormat, msgArgs...),
+		}
+		select {
+		case w.Base().Queue <- formatted:
+		default:
+			bs, _ := json.Marshal(event)
+			FallbackErrorf("log writer %q queue is full, event: %v", w.GetWriterName(), string(bs))
+		}
+	}
+}
+
+// syncLevelInternal syncs the level of the logger with the levels of the writers
+func (l *LoggerImpl) syncLevelInternal() {
+	lowestLevel := NONE
+	for _, w := range l.eventWriters {
+		if w.GetLevel() < lowestLevel {
+			lowestLevel = w.GetLevel()
+		}
+	}
+	l.level.Store(int32(lowestLevel))
+
+	lowestLevel = NONE
+	for _, w := range l.eventWriters {
+		if w.Base().Mode.StacktraceLevel < lowestLevel {
+			lowestLevel = w.GetLevel()
+		}
+	}
+	l.stacktraceLevel.Store(int32(lowestLevel))
+}
+
+// removeWriterInternal removes a writer from the logger, and stops it if it's not shared
+func (l *LoggerImpl) removeWriterInternal(w EventWriter) {
+	if !w.Base().shared {
+		eventWriterStopWait(w) // only stop non-shared writers, shared writers are managed by the manager
+	}
+	delete(l.eventWriters, w.GetWriterName())
+}
+
+// AddWriters adds writers to the logger, and starts them. Existing writers will be replaced by new ones.
+func (l *LoggerImpl) AddWriters(writer ...EventWriter) {
+	l.eventWriterMu.Lock()
+	defer l.eventWriterMu.Unlock()
+	l.addWritersInternal(writer...)
+}
+
+func (l *LoggerImpl) addWritersInternal(writer ...EventWriter) {
+	for _, w := range writer {
+		if old, ok := l.eventWriters[w.GetWriterName()]; ok {
+			l.removeWriterInternal(old)
+		}
+	}
+
+	for _, w := range writer {
+		l.eventWriters[w.GetWriterName()] = w
+		eventWriterStartGo(l.ctx, w, false)
+	}
+
+	l.syncLevelInternal()
+}
+
+// RemoveWriter removes a writer from the logger, and the writer is closed and flushed if it is not shared
+func (l *LoggerImpl) RemoveWriter(modeName string) error {
+	l.eventWriterMu.Lock()
+	defer l.eventWriterMu.Unlock()
+
+	w, ok := l.eventWriters[modeName]
+	if !ok {
+		return util.ErrNotExist
+	}
+
+	l.removeWriterInternal(w)
+	l.syncLevelInternal()
+	return nil
+}
+
+// ReplaceAllWriters replaces all writers from the logger, non-shared writers are closed and flushed
+func (l *LoggerImpl) ReplaceAllWriters(writer ...EventWriter) {
+	l.eventWriterMu.Lock()
+	defer l.eventWriterMu.Unlock()
+
+	for _, w := range l.eventWriters {
+		l.removeWriterInternal(w)
+	}
+	l.eventWriters = map[string]EventWriter{}
+	l.addWritersInternal(writer...)
+}
+
+// DumpWriters dumps the writers as a JSON map, it's used for debugging and display purposes.
+func (l *LoggerImpl) DumpWriters() map[string]any {
+	l.eventWriterMu.RLock()
+	defer l.eventWriterMu.RUnlock()
+
+	writers := make(map[string]any, len(l.eventWriters))
+	for k, w := range l.eventWriters {
+		bs, err := json.Marshal(w.Base().Mode)
+		if err != nil {
+			FallbackErrorf("marshal writer %q to dump failed: %v", k, err)
+			continue
+		}
+		m := map[string]any{}
+		_ = json.Unmarshal(bs, &m)
+		m["WriterType"] = w.GetWriterType()
+		writers[k] = m
+	}
+	return writers
+}
+
+// Close closes the logger, non-shared writers are closed and flushed
+func (l *LoggerImpl) Close() {
+	l.ReplaceAllWriters()
+	l.ctxCancel()
+}
+
+// IsEnabled returns true if the logger is enabled: it has a working level and has writers
+// Fatal is not considered as enabled, because it's a special case and the process just exits
+func (l *LoggerImpl) IsEnabled() bool {
+	l.eventWriterMu.RLock()
+	defer l.eventWriterMu.RUnlock()
+	return l.level.Load() < int32(FATAL) && len(l.eventWriters) > 0
+}
+
+func asLogStringer(v any) LogStringer {
+	if s, ok := v.(LogStringer); ok {
+		return s
+	} else if a := reflect.ValueOf(v); a.Kind() == reflect.Struct {
+		// in case the receiver is a pointer, but the value is a struct
+		vp := reflect.New(a.Type())
+		vp.Elem().Set(a)
+		if s, ok := vp.Interface().(LogStringer); ok {
+			return s
+		}
+	}
+	return nil
+}
+
+// Log prepares the log event, if the level matches, the event will be sent to the writers
+func (l *LoggerImpl) Log(skip int, event *Event, format string, logArgs ...any) {
+	if Level(l.level.Load()) > event.Level {
+		return
+	}
+
+	if event.Time.IsZero() {
+		event.Time = time.Now()
+	}
+	if event.Caller == "" {
+		pc, filename, line, ok := runtime.Caller(skip + 1)
+		if ok {
+			fn := runtime.FuncForPC(pc)
+			if fn != nil {
+				fnName := fn.Name()
+				event.Caller = strings.ReplaceAll(fnName, "[...]", "") + "()" // generic function names are "foo[...]"
+			}
+		}
+		event.Filename, event.Line = strings.TrimPrefix(filename, projectPackagePrefix), line
+		if l.stacktraceLevel.Load() <= int32(event.Level) {
+			event.Stacktrace = Stack(skip + 1)
+		}
+	}
+
+	// get a simple text message without color
+	msgArgs := make([]any, len(logArgs))
+	copy(msgArgs, logArgs)
+
+	// handle LogStringer values
+	for i, v := range msgArgs {
+		if cv, ok := v.(*ColoredValue); ok {
+			if ls := asLogStringer(cv.v); ls != nil {
+				cv.v = logStringFormatter{v: ls}
+			}
+		} else if ls := asLogStringer(v); ls != nil {
+			msgArgs[i] = logStringFormatter{v: ls}
+		}
+	}
+
+	event.MsgSimpleText = colorSprintf(false, format, msgArgs...)
+	event.msgFormat = format
+	event.msgArgs = msgArgs
+	l.SendLogEvent(event)
+}
+
+func (l *LoggerImpl) GetLevel() Level {
+	return Level(l.level.Load())
+}
+
+func NewLoggerWithWriters(ctx context.Context, name string, writer ...EventWriter) *LoggerImpl {
+	l := &LoggerImpl{}
+	l.ctx, l.ctxCancel = newProcessTypedContext(ctx, "Logger: "+name)
+	l.LevelLogger = BaseLoggerToGeneralLogger(l)
+	l.eventWriters = map[string]EventWriter{}
+	l.AddWriters(writer...)
+	return l
+}

modules/log/logger_test.go

@@ -0,0 +1,179 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"regexp"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type dummyWriter struct {
+	*EventWriterBaseImpl
+
+	delay time.Duration
+
+	mu   sync.Mutex
+	logs []string
+}
+
+func (d *dummyWriter) Write(p []byte) (n int, err error) {
+	if d.delay > 0 {
+		time.Sleep(d.delay)
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.logs = append(d.logs, string(p))
+	return len(p), nil
+}
+
+func (d *dummyWriter) Close() error {
+	return nil
+}
+
+func (d *dummyWriter) FetchLogs() []string {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	logs := d.logs
+	d.logs = nil
+	return logs
+}
+
+func newDummyWriter(name string, level Level, delay time.Duration) *dummyWriter {
+	w := &dummyWriter{
+		EventWriterBaseImpl: NewEventWriterBase(name, "dummy", WriterMode{Level: level, Flags: FlagsFromBits(0)}),
+	}
+	w.delay = delay
+	w.Base().OutputWriteCloser = w
+	return w
+}
+
+func TestLogger(t *testing.T) {
+	logger := NewLoggerWithWriters(t.Context(), "test")
+
+	dump := logger.DumpWriters()
+	assert.Empty(t, dump)
+	assert.Equal(t, NONE, logger.GetLevel())
+	assert.False(t, logger.IsEnabled())
+
+	w1 := newDummyWriter("dummy-1", DEBUG, 0)
+	logger.AddWriters(w1)
+	assert.Equal(t, DEBUG, logger.GetLevel())
+
+	w2 := newDummyWriter("dummy-2", WARN, 200*time.Millisecond)
+	logger.AddWriters(w2)
+	assert.Equal(t, DEBUG, logger.GetLevel())
+
+	dump = logger.DumpWriters()
+	assert.Len(t, dump, 2)
+
+	logger.Trace("trace-level") // this level is not logged
+	logger.Debug("debug-level")
+	logger.Error("error-level")
+
+	// w2 is slow, so only w1 has logs
+	time.Sleep(100 * time.Millisecond)
+	assert.Equal(t, []string{"debug-level\n", "error-level\n"}, w1.FetchLogs())
+	assert.Empty(t, w2.FetchLogs())
+
+	logger.Close()
+
+	// after Close, all logs are flushed
+	assert.Empty(t, w1.FetchLogs())
+	assert.Equal(t, []string{"error-level\n"}, w2.FetchLogs())
+}
+
+func TestLoggerPause(t *testing.T) {
+	logger := NewLoggerWithWriters(t.Context(), "test")
+
+	w1 := newDummyWriter("dummy-1", DEBUG, 0)
+	logger.AddWriters(w1)
+
+	GetManager().PauseAll()
+	time.Sleep(50 * time.Millisecond)
+
+	logger.Info("info-level")
+	time.Sleep(100 * time.Millisecond)
+	assert.Empty(t, w1.FetchLogs())
+
+	GetManager().ResumeAll()
+
+	time.Sleep(100 * time.Millisecond)
+	assert.Equal(t, []string{"info-level\n"}, w1.FetchLogs())
+
+	logger.Close()
+}
+
+type testLogString struct {
+	Field string
+}
+
+func (t testLogString) LogString() string {
+	return "log-string"
+}
+
+type testLogStringPtrReceiver struct {
+	Field string
+}
+
+func (t *testLogStringPtrReceiver) LogString() string {
+	return "log-string-ptr-receiver"
+}
+
+func genericFunc[T any](logger Logger, v T) {
+	logger.Info("from genericFunc: %v", v)
+}
+
+func TestLoggerOutput(t *testing.T) {
+	t.Run("LogString", func(t *testing.T) {
+		logger := NewLoggerWithWriters(t.Context(), "test")
+		w1 := newDummyWriter("dummy-1", DEBUG, 0)
+		w1.Mode.Colorize = true
+		logger.AddWriters(w1)
+		logger.Info("%s %s %#v %v", testLogString{}, &testLogString{}, testLogString{Field: "detail"}, NewColoredValue(testLogString{}, FgRed))
+		logger.Info("%s %s %#v %v", testLogStringPtrReceiver{}, &testLogStringPtrReceiver{}, testLogStringPtrReceiver{Field: "detail"}, NewColoredValue(testLogStringPtrReceiver{}, FgRed))
+		logger.Close()
+
+		assert.Equal(t, []string{
+			"log-string log-string log.testLogString{Field:\"detail\"} \x1b[31mlog-string\x1b[0m\n",
+			"log-string-ptr-receiver log-string-ptr-receiver &log.testLogStringPtrReceiver{Field:\"detail\"} \x1b[31mlog-string-ptr-receiver\x1b[0m\n",
+		}, w1.FetchLogs())
+	})
+
+	t.Run("Caller", func(t *testing.T) {
+		logger := NewLoggerWithWriters(t.Context(), "test")
+		w1 := newDummyWriter("dummy-1", DEBUG, 0)
+		w1.EventWriterBaseImpl.Mode.Flags.flags = Lmedfile | Lshortfuncname
+		logger.AddWriters(w1)
+		anonymousFunc := func(logger Logger) {
+			logger.Info("from anonymousFunc")
+		}
+		genericFunc(logger, "123")
+		anonymousFunc(logger)
+		logger.Close()
+		logs := w1.FetchLogs()
+		assert.Len(t, logs, 2)
+		assert.Regexp(t, `modules/log/logger_test.go:\w+:`+regexp.QuoteMeta(`genericFunc() from genericFunc: 123`), logs[0])
+		assert.Regexp(t, `modules/log/logger_test.go:\w+:`+regexp.QuoteMeta(`TestLoggerOutput.2.1() from anonymousFunc`), logs[1])
+	})
+}
+
+func TestLoggerExpressionFilter(t *testing.T) {
+	logger := NewLoggerWithWriters(t.Context(), "test")
+
+	w1 := newDummyWriter("dummy-1", DEBUG, 0)
+	w1.Mode.Expression = "foo.*"
+	logger.AddWriters(w1)
+
+	logger.Info("foo")
+	logger.Info("bar")
+	logger.Info("foo bar")
+	logger.SendLogEvent(&Event{Level: INFO, Filename: "foo.go", MsgSimpleText: "by filename"})
+	logger.Close()
+
+	assert.Equal(t, []string{"foo\n", "foo bar\n", "by filename\n"}, w1.FetchLogs())
+}

modules/log/manager.go

@@ -0,0 +1,142 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"sync/atomic"
+)
+
+const DEFAULT = "default"
+
+// LoggerManager manages loggers and shared event writers
+type LoggerManager struct {
+	ctx       context.Context
+	ctxCancel context.CancelFunc
+
+	mu            sync.Mutex
+	writers       map[string]EventWriter
+	loggers       map[string]*LoggerImpl
+	defaultLogger atomic.Pointer[LoggerImpl]
+
+	pauseMu   sync.RWMutex
+	pauseChan chan struct{}
+}
+
+// GetLogger returns a logger with the given name. If the logger doesn't exist, a new empty one will be created.
+func (m *LoggerManager) GetLogger(name string) *LoggerImpl {
+	if name == DEFAULT {
+		if logger := m.defaultLogger.Load(); logger != nil {
+			return logger
+		}
+	}
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	logger := m.loggers[name]
+	if logger == nil {
+		logger = NewLoggerWithWriters(m.ctx, name)
+		m.loggers[name] = logger
+		if name == DEFAULT {
+			m.defaultLogger.Store(logger)
+		}
+	}
+
+	return logger
+}
+
+// PauseAll pauses all event writers
+func (m *LoggerManager) PauseAll() {
+	m.pauseMu.Lock()
+	m.pauseChan = make(chan struct{})
+	m.pauseMu.Unlock()
+}
+
+// ResumeAll resumes all event writers
+func (m *LoggerManager) ResumeAll() {
+	m.pauseMu.Lock()
+	close(m.pauseChan)
+	m.pauseChan = nil
+	m.pauseMu.Unlock()
+}
+
+// GetPauseChan returns a channel for writer pausing
+func (m *LoggerManager) GetPauseChan() chan struct{} {
+	m.pauseMu.RLock()
+	defer m.pauseMu.RUnlock()
+	return m.pauseChan
+}
+
+// Close closes the logger manager, all loggers and writers will be closed, the messages are flushed.
+func (m *LoggerManager) Close() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	for _, logger := range m.loggers {
+		logger.Close()
+	}
+	m.loggers = map[string]*LoggerImpl{}
+
+	for _, writer := range m.writers {
+		eventWriterStopWait(writer)
+	}
+	m.writers = map[string]EventWriter{}
+
+	m.ctxCancel()
+}
+
+// DumpLoggers returns a map of all loggers and their event writers, for debugging and display purposes.
+func (m *LoggerManager) DumpLoggers() map[string]any {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	dump := map[string]any{}
+	for name, logger := range m.loggers {
+		loggerDump := map[string]any{
+			"IsEnabled":    logger.IsEnabled(),
+			"EventWriters": logger.DumpWriters(),
+		}
+		dump[name] = loggerDump
+	}
+	return dump
+}
+
+// NewSharedWriter creates a new shared event writer, it can be used by multiple loggers, and a shared writer won't be closed if a logger is closed.
+func (m *LoggerManager) NewSharedWriter(writerName, writerType string, mode WriterMode) (writer EventWriter, err error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, ok := m.writers[writerName]; ok {
+		return nil, fmt.Errorf("log event writer %q has been added before", writerName)
+	}
+
+	if writer, err = NewEventWriter(writerName, writerType, mode); err != nil {
+		return nil, err
+	}
+
+	m.writers[writerName] = writer
+	eventWriterStartGo(m.ctx, writer, true)
+	return writer, nil
+}
+
+func (m *LoggerManager) GetSharedWriter(writerName string) EventWriter {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.writers[writerName]
+}
+
+var loggerManager = NewManager()
+
+func GetManager() *LoggerManager {
+	return loggerManager
+}
+
+func NewManager() *LoggerManager {
+	m := &LoggerManager{writers: map[string]EventWriter{}, loggers: map[string]*LoggerImpl{}}
+	m.ctx, m.ctxCancel = newProcessTypedContext(context.Background(), "LoggerManager")
+	return m
+}

modules/log/manager_test.go

@@ -0,0 +1,42 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSharedWorker(t *testing.T) {
+	RegisterEventWriter("dummy", func(writerName string, writerMode WriterMode) EventWriter {
+		return newDummyWriter(writerName, writerMode.Level, 0)
+	})
+
+	m := NewManager()
+	_, err := m.NewSharedWriter("dummy-1", "dummy", WriterMode{Level: DEBUG, Flags: FlagsFromBits(0)})
+	assert.NoError(t, err)
+
+	w := m.GetSharedWriter("dummy-1")
+	assert.NotNil(t, w)
+	loggerTest := m.GetLogger("test")
+	loggerTest.AddWriters(w)
+	loggerTest.Info("msg-1")
+	loggerTest.ReplaceAllWriters() // the shared writer is not closed here
+	loggerTest.Info("never seen")
+
+	// the shared writer can still be used later
+	w = m.GetSharedWriter("dummy-1")
+	assert.NotNil(t, w)
+	loggerTest.AddWriters(w)
+	loggerTest.Info("msg-2")
+
+	m.GetLogger("test-another").AddWriters(w)
+	m.GetLogger("test-another").Info("msg-3")
+
+	m.Close()
+
+	logs := w.(*dummyWriter).FetchLogs()
+	assert.Equal(t, []string{"msg-1\n", "msg-2\n", "msg-3\n"}, logs)
+}

modules/log/misc.go

@@ -0,0 +1,78 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"io"
+)
+
+type baseToLogger struct {
+	base BaseLogger
+}
+
+// BaseLoggerToGeneralLogger wraps a BaseLogger (which only has Log() function) to a Logger (which has Info() function)
+func BaseLoggerToGeneralLogger(b BaseLogger) Logger {
+	l := &baseToLogger{base: b}
+	return l
+}
+
+var _ Logger = (*baseToLogger)(nil)
+
+func (s *baseToLogger) Log(skip int, event *Event, format string, v ...any) {
+	s.base.Log(skip+1, event, format, v...)
+}
+
+func (s *baseToLogger) GetLevel() Level {
+	return s.base.GetLevel()
+}
+
+func (s *baseToLogger) LevelEnabled(level Level) bool {
+	return s.base.GetLevel() <= level
+}
+
+func (s *baseToLogger) Trace(format string, v ...any) {
+	s.base.Log(1, &Event{Level: TRACE}, format, v...)
+}
+
+func (s *baseToLogger) Debug(format string, v ...any) {
+	s.base.Log(1, &Event{Level: DEBUG}, format, v...)
+}
+
+func (s *baseToLogger) Info(format string, v ...any) {
+	s.base.Log(1, &Event{Level: INFO}, format, v...)
+}
+
+func (s *baseToLogger) Warn(format string, v ...any) {
+	s.base.Log(1, &Event{Level: WARN}, format, v...)
+}
+
+func (s *baseToLogger) Error(format string, v ...any) {
+	s.base.Log(1, &Event{Level: ERROR}, format, v...)
+}
+
+func (s *baseToLogger) Critical(format string, v ...any) {
+	s.base.Log(1, &Event{Level: CRITICAL}, format, v...)
+}
+
+type PrintfLogger struct {
+	Logf func(format string, args ...any)
+}
+
+func (p *PrintfLogger) Printf(format string, args ...any) {
+	p.Logf(format, args...)
+}
+
+type loggerToWriter struct {
+	logf func(format string, args ...any)
+}
+
+func (p *loggerToWriter) Write(bs []byte) (int, error) {
+	p.logf("%s", string(bs))
+	return len(bs), nil
+}
+
+// LoggerToWriter wraps a log function to an io.Writer
+func LoggerToWriter(logf func(format string, args ...any)) io.Writer {
+	return &loggerToWriter{logf: logf}
+}

modules/log/stack.go

@@ -0,0 +1,80 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"runtime"
+)
+
+var unknown = []byte("???")
+
+// Stack will skip back the provided number of frames and return a stack trace with source code.
+// Although we could just use debug.Stack(), this routine will return the source code and
+// skip back the provided number of frames - i.e. allowing us to ignore preceding function calls.
+// A skip of 0 returns the stack trace for the calling function, not including this call.
+// If the problem is a lack of memory of course all this is not going to work...
+func Stack(skip int) string {
+	buf := new(bytes.Buffer)
+
+	// Store the last file we opened as its probable that the preceding stack frame
+	// will be in the same file
+	var lines [][]byte
+	var lastFilename string
+	for i := skip + 1; ; i++ { // Skip over frames
+		programCounter, filename, lineNumber, ok := runtime.Caller(i)
+		// If we can't retrieve the information break - basically we're into go internals at this point.
+		if !ok {
+			break
+		}
+
+		// Print equivalent of debug.Stack()
+		_, _ = fmt.Fprintf(buf, "%s:%d (0x%x)\n", filename, lineNumber, programCounter)
+		// Now try to print the offending line
+		if filename != lastFilename {
+			data, err := os.ReadFile(filename)
+			if err != nil {
+				// can't read this source file
+				// likely we don't have the sourcecode available
+				continue
+			}
+			lines = bytes.Split(data, []byte{'\n'})
+			lastFilename = filename
+		}
+		_, _ = fmt.Fprintf(buf, "\t%s: %s\n", functionName(programCounter), source(lines, lineNumber))
+	}
+	return buf.String()
+}
+
+// functionName converts the provided programCounter into a function name
+func functionName(programCounter uintptr) []byte {
+	function := runtime.FuncForPC(programCounter)
+	if function == nil {
+		return unknown
+	}
+	name := []byte(function.Name())
+
+	// Because we provide the filename we can drop the preceding package name.
+	if lastslash := bytes.LastIndex(name, []byte("/")); lastslash >= 0 {
+		name = name[lastslash+1:]
+	}
+	// And the current package name.
+	if period := bytes.Index(name, []byte(".")); period >= 0 {
+		name = name[period+1:]
+	}
+	// And we should just replace the interpunct with a dot
+	name = bytes.ReplaceAll(name, []byte("·"), []byte("."))
+	return name
+}
+
+// source returns a space-trimmed slice of the n'th line.
+func source(lines [][]byte, n int) []byte {
+	n-- // in stack trace, lines are 1-indexed but our array is 0-indexed
+	if n < 0 || n >= len(lines) {
+		return unknown
+	}
+	return bytes.TrimSpace(lines[n])
+}