package logos

import (

"fmt"

"os"

"go.uber.org/zap"

"go.uber.org/zap/zapcore"

lumberjack "gopkg.in/natefinch/lumberjack.v2"

)

// printw formats and prints a msg and keys and values to a stream.

// Useful when you need to show info but you don't have a log

func printw(fp *os.File, level string, msg string, keysAndValues ...interface{}) {

msg = level + ": " + msg

length := len(keysAndValues)

if length%2 != 0 {

panic(fmt.Sprintf("len() not even - keysAndValues: %#v\n", keysAndValues))

}

keys := make([]string, length/2)

values := make([]interface{}, length/2)

for i := 0; i < length/2; i++ {

keys[i] = keysAndValues[i*2].(string)

values[i] = keysAndValues[i*2+1]

}

fmtStr := msg + "\n"

for i := 0; i < length/2; i++ {

fmtStr += (" " + keys[i] + ": %#v\n")

}

fmtStr += "\n"

fmt.Fprintf(fp, fmtStr, values...)

}

// Logger is a very opinionated wrapper around a uber/zap sugared logger

// It's designed primarily to simultaneously print "pretty-enough" input for a

// user and useful enough info to a lumberjack logger

// It should really only be used with simple key/value pairs

// It's designed to be fairly easily swappable with the sugared logger

type Logger struct {

logger *zap.Logger

sugar *zap.SugaredLogger

}

// Infow prints a message and keys and values with INFO level

func (l *Logger) Infow(msg string, keysAndValues ...interface{}) {

l.sugar.Infow(msg, keysAndValues...)

printw(os.Stdout, "INFO", msg, keysAndValues...)

}

func Infow(msg string, keysAndValues ...interface{}) {

printw(os.Stdout, "INFO", msg, keysAndValues...)

}

// Errorw prints a message and keys and values with INFO level

func (l *Logger) Errorw(msg string, keysAndValues ...interface{}) {

l.sugar.Errorw(msg, keysAndValues...)

printw(os.Stderr, "ERROR", msg, keysAndValues...)

}

func Errorw(msg string, keysAndValues ...interface{}) {

printw(os.Stderr, "ERROR", msg, keysAndValues...)

}

// Debugw prints keys and values only to the log, not to the user

func (l *Logger) Debugw(msg string, keysAndValues ...interface{}) {

l.sugar.Debugw(msg, keysAndValues...)

}

// Sync syncs the underlying logger

func (l *Logger) Sync() error {

return l.logger.Sync()

}

// LogOnPanic tries to log a panic. It should be called at the start of each

// goroutine. See panic and recover docs

func (l *Logger) LogOnPanic() {

stackTraceSugar := l.logger.

WithOptions(

zap.AddStacktrace(zap.PanicLevel),

).

Sugar()

if err := recover(); err != nil {

stackTraceSugar.Panicw(

"panic found!",

"err", err,

)

}

}

// NewLogger builds a new Logger

func NewLogger(zapLogger *zap.Logger) *Logger {

return &Logger{

// logger is useful for syncs and panics

logger: zapLogger,

// sugar is a wrapper to call the things we actually care about :)

sugar: zapLogger.WithOptions(zap.AddCallerSkip(1)).Sugar(),

}

}

// NewZapSugaredLogger builds a zap.SugaredLogger configured with settings I like

// If lumberjackLogger == nil, then it returns an No-op logger,

// which can be useful when you want to use the library, but not have a log file

func NewZapSugaredLogger(lumberjackLogger *lumberjack.Logger, lvl zapcore.LevelEnabler, appVersion string) *zap.Logger {

if lumberjackLogger == nil {

return zap.NewNop()

}

encoderConfig := zapcore.EncoderConfig{

// prefix shared keys with '_' so they show up first when keys are alphabetical

TimeKey: "_timestamp",

LevelKey: "_level",

NameKey: "_name", // TODO: what is this?

CallerKey: "_caller",

FunctionKey: "_function", // zapcore.OmitKey,

MessageKey: "_msg",

StacktraceKey: "_stacktrace",

LineEnding: zapcore.DefaultLineEnding,

EncodeLevel: zapcore.CapitalLevelEncoder,

EncodeTime: zapcore.ISO8601TimeEncoder,

EncodeDuration: zapcore.StringDurationEncoder,

EncodeCaller: zapcore.ShortCallerEncoder,

}

customCommonFields := zap.Fields(

zap.Int("_pid", os.Getpid()),

zap.String("_version", appVersion),

)

jsonCore := zapcore.NewCore(

zapcore.NewJSONEncoder(encoderConfig),

zapcore.AddSync(lumberjackLogger),

lvl,

)

logger := zap.New(

jsonCore,

zap.AddCaller(),

// Using errors package to get better stack traces

// zap.AddStacktrace(stackTraceLvl),

customCommonFields,

)

return logger

}