package log
import (
"bytes"
"encoding/json"
"fmt"
"reflect"
"strconv"
"strings"
"sync"
"time"
)
const (
timeFormat = "2006-01-02T15:04:05-0700"
termTimeFormat = "01-02|15:04:05"
floatFormat = 'f'
termMsgJust = 40
)
type Format interface {
Format(r *Record) []byte
}
// FormatFunc returns a new Format object which uses
// the given function to perform record formatting.
func FormatFunc(f func(*Record) []byte) Format {
return formatFunc(f)
}
type formatFunc func(*Record) []byte
func (f formatFunc) Format(r *Record) []byte {
return f(r)
}
// 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() Format {
return FormatFunc(func(r *Record) []byte {
var color = 0
switch r.Lvl {
case LvlCrit:
color = 35
case LvlError:
color = 31
case LvlWarn:
color = 33
case LvlInfo:
color = 32
case LvlDebug:
color = 36
}
b := &bytes.Buffer{}
lvl := strings.ToUpper(r.Lvl.String())
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
if len(r.Ctx) > 0 && len(r.Msg) < termMsgJust {
b.Write(bytes.Repeat([]byte{' '}, termMsgJust-len(r.Msg)))
}
// print the keys logfmt style
logfmt(b, r.Ctx, color)
return b.Bytes()
})
}
// LogfmtFormat prints records in logfmt format, an easy machine-parseable but human-readable
// format for key/value pairs.
//
// For more details see: http://godoc.org/github.com/kr/logfmt
//
func LogfmtFormat() Format {
return FormatFunc(func(r *Record) []byte {
common := []interface{}{r.KeyNames.Time, r.Time, r.KeyNames.Lvl, r.Lvl, r.KeyNames.Msg, r.Msg}
buf := &bytes.Buffer{}
logfmt(buf, append(common, r.Ctx...), 0)
return buf.Bytes()
})
}
func logfmt(buf *bytes.Buffer, ctx []interface{}, color int) {
for i := 0; i < len(ctx); i += 2 {
if i != 0 {
buf.WriteByte(' ')
}
k, ok := ctx[i].(string)
v := formatLogfmtValue(ctx[i+1])
if !ok {
k, v = errorKey, formatLogfmtValue(k)
}
// XXX: we should probably check that all of your key bytes aren't invalid
if color > 0 {
fmt.Fprintf(buf, "\x1b[%dm%s\x1b[0m=%s", color, k, v)
} else {
buf.WriteString(k)
buf.WriteByte('=')
buf.WriteString(v)
}
}
buf.WriteByte('\n')
}
// JsonFormat formats log records as JSON objects separated by newlines.
// It is the equivalent of JsonFormatEx(false, true).
func JsonFormat() Format {
return JsonFormatEx(false, true)
}
// JsonFormatEx formats log records as JSON objects. If pretty is true,
// records will be pretty-printed. If lineSeparated is true, records
// will be logged with a new line between each record.
func JsonFormatEx(pretty, lineSeparated bool) Format {
jsonMarshal := json.Marshal
if pretty {
jsonMarshal = func(v interface{}) ([]byte, error) {
return json.MarshalIndent(v, "", " ")
}
}
return FormatFunc(func(r *Record) []byte {
props := make(map[string]interface{})
props[r.KeyNames.Time] = r.Time
props[r.KeyNames.Lvl] = r.Lvl.String()
props[r.KeyNames.Msg] = r.Msg
for i := 0; i < len(r.Ctx); i += 2 {
k, ok := r.Ctx[i].(string)
if !ok {
props[errorKey] = fmt.Sprintf("%+v is not a string key", r.Ctx[i])
}
props[k] = formatJsonValue(r.Ctx[i+1])
}
b, err := jsonMarshal(props)
if err != nil {
b, _ = jsonMarshal(map[string]string{
errorKey: err.Error(),
})
return b
}
if lineSeparated {
b = append(b, '\n')
}
return b
})
}
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
}
}
func formatJsonValue(value interface{}) interface{} {
value = formatShared(value)
switch value.(type) {
case int, int8, int16, int32, int64, float32, float64, uint, uint8, uint16, uint32, uint64, string:
return value
default:
return fmt.Sprintf("%+v", value)
}
}
// formatValue formats a value for serialization
func formatLogfmtValue(value interface{}) 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)
}
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 == false && needsQuotes == false {
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
}
