/
format.go
279 lines (254 loc) · 6.69 KB
/
format.go
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package log
import (
"bytes"
"fmt"
"github.com/go-stack/stack"
"github.com/inconshreveable/log15"
"reflect"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"unicode/utf8"
)
const (
timeFormat = "2006-01-02T15:04:05-0700"
termTimeFormat = "01-02|15:04:05"
floatFormat = 'f'
termMsgJust = 40
errorKey = "LOG15_ERROR"
)
// locationTrims are trimmed for display to avoid unwieldy log lines.
var locationTrims = []string{
"github.com/LemoFoundationLtd/",
}
// locationLength is the maxmimum path length encountered, which all logs are
// padded to to aid in alignment.
var locationLength uint32
// fieldPadding is a global map with maximum field value lengths seen until now
// to allow padding log contexts in a bit smarter way.
var fieldPadding = make(map[string]int)
// fieldPaddingLock is a global mutex protecting the field padding map.
var fieldPaddingLock sync.RWMutex
// TerminalStringer is an analogous interface to the stdlib stringer, allowing
// own types to have custom shortened serialization formats when printed to the
// screen.
type TerminalStringer interface {
TerminalString() string
}
// TerminalFormat formats log records optimized for human readability on
// a terminal with color-coded level output and terser human friendly timestamp.
// This format should only be used for interactive programs or while developing.
//
// [TIME] [LEVEL] MESAGE key=value key=value ...
//
// Example:
//
// [May 16 20:58:45] [DBUG] remove route ns=haproxy addr=127.0.0.1:50002
//
func TerminalFormat(usecolor bool, showCodeLine bool) log15.Format {
return log15.FormatFunc(func(r *log15.Record) []byte {
var color = 0
if usecolor {
switch r.Lvl {
case log15.LvlCrit:
color = 35
case log15.LvlError:
color = 31
case log15.LvlWarn:
color = 33
case log15.LvlInfo:
color = 32
case log15.LvlDebug:
color = 36
}
}
b := &bytes.Buffer{}
lvl := getAlignedString(r.Lvl)
if showCodeLine {
// Log origin printing was requested, format the location path and line number
location := fmt.Sprintf("%+v", stack.Caller(16))
for _, prefix := range locationTrims {
location = strings.TrimPrefix(location, prefix)
}
// Maintain the maximum location length for fancyer alignment
align := int(atomic.LoadUint32(&locationLength))
if align < len(location) {
align = len(location)
atomic.StoreUint32(&locationLength, uint32(align))
}
padding := strings.Repeat(" ", align-len(location))
// Assemble and print the log heading
if color > 0 {
fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%s|%s]%s %s ", color, lvl, r.Time.Format(termTimeFormat), location, padding, r.Msg)
} else {
fmt.Fprintf(b, "%s[%s|%s]%s %s ", lvl, r.Time.Format(termTimeFormat), location, padding, r.Msg)
}
} else {
if color > 0 {
fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%s] %s ", color, lvl, r.Time.Format(termTimeFormat), r.Msg)
} else {
fmt.Fprintf(b, "%s[%s] %s ", lvl, r.Time.Format(termTimeFormat), r.Msg)
}
}
// try to justify the log output for short messages
length := utf8.RuneCountInString(r.Msg)
if len(r.Ctx) > 0 && length < termMsgJust {
b.Write(bytes.Repeat([]byte{' '}, termMsgJust-length))
}
// print the keys logfmt style
logfmt(b, r.Ctx, color, true)
return b.Bytes()
})
}
// Aligned returns a 5-character string containing the name of a Level.
func getAlignedString(l log15.Lvl) string {
switch l {
case log15.LvlDebug:
return "DEBUG"
case log15.LvlInfo:
return "INFO "
case log15.LvlWarn:
return "WARN "
case log15.LvlError:
return "ERROR"
case log15.LvlCrit:
return "CRIT "
default:
panic("bad level")
}
}
func logfmt(buf *bytes.Buffer, ctx []interface{}, color int, term bool) {
for i := 0; i < len(ctx); i += 2 {
if i != 0 {
buf.WriteByte(' ')
}
k, ok := ctx[i].(string)
v := formatLogfmtValue(ctx[i+1], term)
if !ok {
k, v = errorKey, formatLogfmtValue(k, term)
}
// XXX: we should probably check that all of your key bytes aren't invalid
fieldPaddingLock.RLock()
padding := fieldPadding[k]
fieldPaddingLock.RUnlock()
length := utf8.RuneCountInString(v)
if padding < length {
padding = length
fieldPaddingLock.Lock()
fieldPadding[k] = padding
fieldPaddingLock.Unlock()
}
if color > 0 {
fmt.Fprintf(buf, "\x1b[%dm%s\x1b[0m=", color, k)
} else {
buf.WriteString(k)
buf.WriteByte('=')
}
buf.WriteString(v)
if i < len(ctx)-2 {
buf.Write(bytes.Repeat([]byte{' '}, padding-length))
}
}
buf.WriteByte('\n')
}
func formatShared(value interface{}) (result interface{}) {
defer func() {
if err := recover(); err != nil {
if v := reflect.ValueOf(value); v.Kind() == reflect.Ptr && v.IsNil() {
result = "nil"
} else {
panic(err)
}
}
}()
switch v := value.(type) {
case time.Time:
return v.Format(timeFormat)
case error:
return v.Error()
case fmt.Stringer:
return v.String()
default:
return v
}
}
// formatValue formats a value for serialization
func formatLogfmtValue(value interface{}, term bool) string {
if value == nil {
return "nil"
}
if t, ok := value.(time.Time); ok {
// Performance optimization: No need for escaping since the provided
// timeFormat doesn't have any escape characters, and escaping is
// expensive.
return t.Format(timeFormat)
}
if term {
if s, ok := value.(TerminalStringer); ok {
// Custom terminal stringer provided, use that
return escapeString(s.TerminalString())
}
}
value = formatShared(value)
switch v := value.(type) {
case bool:
return strconv.FormatBool(v)
case float32:
return strconv.FormatFloat(float64(v), floatFormat, 3, 64)
case float64:
return strconv.FormatFloat(v, floatFormat, 3, 64)
case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
return fmt.Sprintf("%d", value)
case string:
return escapeString(v)
default:
return escapeString(fmt.Sprintf("%+v", value))
}
}
var stringBufPool = sync.Pool{
New: func() interface{} { return new(bytes.Buffer) },
}
func escapeString(s string) string {
needsQuotes := false
needsEscape := false
for _, r := range s {
if r <= ' ' || r == '=' || r == '"' {
needsQuotes = true
}
if r == '\\' || r == '"' || r == '\n' || r == '\r' || r == '\t' {
needsEscape = true
}
}
if !needsEscape && !needsQuotes {
return s
}
e := stringBufPool.Get().(*bytes.Buffer)
e.WriteByte('"')
for _, r := range s {
switch r {
case '\\', '"':
e.WriteByte('\\')
e.WriteByte(byte(r))
case '\n':
e.WriteString("\\n")
case '\r':
e.WriteString("\\r")
case '\t':
e.WriteString("\\t")
default:
e.WriteRune(r)
}
}
e.WriteByte('"')
var ret string
if needsQuotes {
ret = e.String()
} else {
ret = string(e.Bytes()[1 : e.Len()-1])
}
e.Reset()
stringBufPool.Put(e)
return ret
}