lg

package
v1.0.2 Latest Latest
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 Go to latest Published: Jul 31, 2023 License: Apache-2.0 Imports: 25 Imported by: 0

README

Logging helper

Basic

There are four levels of logs:

  • INFO: Normal processing log message. Sink: stdout
  • ERROR: Recoverable error log message. Sink: stderr
  • DEBUG: Misc log message. Only enable when debug mode is on. Sink: stdout
  • FATAL: Unrecoverable error log message. It will panic the application. It should only be triggered for any error caused by Non-user input. Sink: stderr

Methods

Multiple logging interfaces are provided in this lg package:

  • {{Level}}(v ...interface{}): The simplest method to log one or more strings/variables.
  • {{Level}}f(format string, v ...interface{}): Format the log with c-style printf format.
  • {{Level}}c(ctx context.Context, format string, v ...interface{}): This method accept a log context to inherit parameters from parent With() output.
  • With(ctx context.Context, format string, v ...interface{}): This method writes no actual log. Instead, it returns a log context for ancestor application.

Best practice

It's best for log analyser, like Kibana/ElasticSearch, to process structure data Ref.

You are suggested to use Xxxc() series( Infoc, Errorc etc.) logging method to write log. The format string should compose multiple pairs of key/value paramters, like name=%s price=%.2f, with = between key and value descriptor.

Example:

func Somefunc(ctx context.Context, in *pb.Request) (*pb.Reply, error) {
    ctx = lg.With(ctx, "board_id=%s user_id=%s", in.GetBoardId(), in.GetUserId())

    // Do actual logic ...
    lg.Infoc(ctx, "Done")
    // Output:
    // [INFO]2019/07/02 07:25:51 Done board_id=12345 user_id=67890
}

Timezone

Beware! The log record will be logged in UTC timezone, instead of China +0800. This is designed to fit our applications into datacenters in different timezones.

Production deployment

(No mandatory right now) To deploy applications to production environment, it would be better to set JSON output encoding with lg.SetEncoding(lg.TypeJSON), so that the filebeat can automatically collected the structured log, and help analysis.

Documentation

Index

Constants

View Source 
const SlowPrefix = "!SLOW! "

Variables

This section is empty.

Functions

func DPanicError 

func DPanicError(err error)

DPanicError provide a quick way to check unexpected errors that should never happen. It's almost the same as Check(), except only in debug mode will throw panic.

func Debug 

func Debug(v ...interface{})

Debug prints info to standard output with [DEBUG] prefix in debug mode.

func Debugc 

func Debugc(ctx context.Context, msg string, v ...interface{})

Debugc logs debug message in logfmt.

func Debugf 

func Debugf(msg string, v ...interface{})

Debugf except accepting formating info.

func Derive 

func Derive(src, dest context.Context) context.Context

Derive extracts log context from src context, to merge it into dest context.

func EnableDebug 

func EnableDebug()

EnableDebug ...

func Error 

func Error(v ...interface{})

Error prints error to error output with [ERROR] prefix.

func Errorc 

func Errorc(ctx context.Context, msg string, v ...interface{})

Errorc logs error message in logfmt.

func Errorf 

func Errorf(msg string, v ...interface{})

Errorf except accepting formating info.

func Fatal 

func Fatal(v ...interface{})

Fatal prints error to error output with [FATAL] prefix, and terminate the application.

func Fatalc 

func Fatalc(ctx context.Context, msg string, v ...interface{})

Fatalc logs debug message in logfmt. see `Fatal()` for more detail.

func Fatalf 

func Fatalf(msg string, v ...interface{})

Fatalf except accepting formating info.

func ForkLog 

func ForkLog(tailBytes int) io.ReadCloser

func GetFuncName 

func GetFuncName(i interface{}) string

GetFuncName provides shortcut to print the name of any function.

func Info 

func Info(v ...interface{})

Info prints info to standard output with [INFO] prefix.

func Infoc 

func Infoc(ctx context.Context, msg string, v ...interface{})

Infoc logs message in logfmt.

func Infof 

func Infof(msg string, v ...interface{})

Infof except accepting formating info.

func InterceptLogs 

func InterceptLogs(w io.Writer) io.Writer

func IsDebugging 

func IsDebugging() bool

IsDebugging returns whether it's in debug mode.

func Jsonify 

func Jsonify(v interface{}) string

Jsonify provides shortcut to return an json format string of any varible.

func JsonifyNested 

func JsonifyNested(v interface{}) string

func PanicError 

func PanicError(err error, msg ...interface{})

PanicError provide a quick way to check unexpected errors that should never happen. It's basically an assertion that once err != nil, fatal panic is thrown.

func PrintJSON 

func PrintJSON(v interface{})

PrintJSON outputs any varible in JSON format to console. Useful for debuging.

func PrintJSONc 

func PrintJSONc(ctx context.Context, v interface{})

PrintJSONc outputs any varible in JSON format to console, and logger within context. Useful for debuging.

func SetEncoding 

func SetEncoding(t EncodingType)

SetEncoding changes the log encoding type.

func StreamClientInterceptor 

func StreamClientInterceptor(from string) func(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error)

StreamClientInterceptor injects log context into outgoing grpc request.

func StreamServerInterceptor 

func StreamServerInterceptor(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error

StreamServerInterceptor retrieve log context from incoming grpc request.

func TimeDebugc 

func TimeDebugc(ctx context.Context, msg string, v ...interface{}) func()

func TimeFunc 

func TimeFunc(v ...interface{}) func()

TimeFunc prints the info with timing consumed by function. It has specified usage like: 

defer TimeFunc("Hello world")()

func TimeFuncDebug 

func TimeFuncDebug(v ...interface{}) func()

func TimeFuncDuration 

func TimeFuncDuration() func() time.Duration

TimeFuncDuration returns the duration consumed by function. It has specified usage like: 

    f := TimeFuncDuration()
	   DoSomething()
	   duration := f()

func TimeInfoc 

func TimeInfoc(ctx context.Context, msg string, v ...interface{}) func()

func TimeInfocSlow 

func TimeInfocSlow(ctx context.Context, slowDuration time.Duration, msg string, v ...interface{}) func()

TimeInfocSlow prints the info with timing consumed by function. If the cost is larger than slowDuration, it will be printed with !SLOW! prefix before msg.

func UnaryClientInterceptor 

func UnaryClientInterceptor(from string) func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error

UnaryClientInterceptor injects log context into outgoing grpc request.

func UnaryServerInterceptor 

func UnaryServerInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error)

UnaryServerInterceptor retrieve log context from incoming grpc request.

func Warn 

func Warn(v ...interface{})

Warn prints warn to warn output with [WARN] prefix.

func Warnc 

func Warnc(ctx context.Context, msg string, v ...interface{})

Warnc logs warn message in logfmt.

func Warnf 

func Warnf(msg string, v ...interface{})

Warnf except accepting formating info.

func With 

func With(ctx context.Context, msg string, v ...interface{}) context.Context

With wraps a new context, ands inject log context messge into it.

func WithKV 

func WithKV(ctx context.Context, key string, val interface{}) context.Context

WithKV returns a copy of ctx, which will print "{key}={val}" with the log when use methods like Infoc()

func WithLogger 

func WithLogger(ctx context.Context, w io.Writer) context.Context

Types

type EncodingType 

type EncodingType string

EncodingType represent the type to use for log encoding. 

const (
	// TypeJSON encodes log into one-line json.
	TypeJSON EncodingType = "json"

	// TypeLogfmt encodes log into logfmt(structlog) format.
	TypeLogfmt EncodingType = "logfmt"
)

type LogContext 

type LogContext struct {
	// contains filtered or unexported fields
}

LogContext indicates all the contextual logs in a request.

func FromContext 

func FromContext(ctx context.Context) *LogContext

FromContext returns a the potential LogContext object from Context if any.

func (*LogContext) Empty 

func (lc *LogContext) Empty() bool

Empty returns true if the log context contains nothing.

func (*LogContext) From 

func (lc *LogContext) From() string

func (*LogContext) JSON 

func (lc *LogContext) JSON() string

JSON returns the log in JSON format.

func (*LogContext) Logfmt 

func (lc *LogContext) Logfmt(enableColor bool) string

Logfmt returns the log in LOGFMT format.

func (*LogContext) Map 

func (lc *LogContext) Map() map[string]string

func (*LogContext) Message 

func (lc *LogContext) Message() string

func (*LogContext) Since 

func (lc *LogContext) Since() time.Time

func (*LogContext) String 

func (lc *LogContext) String() string

String returns a string representing the log.

func (*LogContext) UUID 

func (lc *LogContext) UUID() int64

type Span 

type Span struct {
	// contains filtered or unexported fields
}

type StripColorReader 

type StripColorReader struct {
	// contains filtered or unexported fields
}

func NewStripColorReader 

func NewStripColorReader(r io.Reader) *StripColorReader

func (*StripColorReader) Read 

func (scr *StripColorReader) Read(p []byte) (int, error)

type StripColorWriter 

type StripColorWriter struct {
	// contains filtered or unexported fields
}

func NewStripColorWriter 

func NewStripColorWriter(w io.Writer) *StripColorWriter

func (*StripColorWriter) Write 

func (scw *StripColorWriter) Write(p []byte) (int, error)

type StripPrefixReader 

type StripPrefixReader struct {
	// contains filtered or unexported fields
}

func NewStripPrefixReader 

func NewStripPrefixReader(r io.Reader, prefix []byte) *StripPrefixReader

func (*StripPrefixReader) Read 

func (scr *StripPrefixReader) Read(p []byte) (int, error)

type Terminal 

type Terminal struct {
	// contains filtered or unexported fields
}

func NewTerminal 

func NewTerminal(maxBufSize int) *Terminal

func (*Terminal) ForkTTY 

func (t *Terminal) ForkTTY(tailBytes int) *tty

func (*Terminal) Write 

func (t *Terminal) Write(p []byte) (int, error)

type Timer 

type Timer struct {
	// contains filtered or unexported fields
}

Timer is a helper to time multiple tick. Simple usage like: ``` t := lg.NewTimer("Search similar", itemID) defer lg.Info(t) meta := getMeta(itemID) t.Tick("Get meta") results := querySimilar(itemID) t.Tick("Query") return formatResult(results) ```

func NewTimer 

func NewTimer(msg ...interface{}) *Timer

NewTimer returns a Timer object.

func (*Timer) Duration 

func (t *Timer) Duration() time.Duration

func (*Timer) String 

func (t *Timer) String() string

func (*Timer) SubTimer 

func (t *Timer) SubTimer(msg ...interface{}) *Timer

SubTimer starts a new timer whose data returns to its parent timer.

func (*Timer) Tick 

func (t *Timer) Tick(msg ...interface{})

Tick records the time ecaplsed since start of timer.

Source Files

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