wrapper.go

// Copyright (C) 2010, Kyle Lemons <kyle@kylelemons.net>.  All rights reserved.

package log4go

import (
	"errors"
	"fmt"
	"net/http"
	"os"
	"strings"
	"time"
)

var (
	Global Logger
)

func init() {
	Global = NewDefaultLogger(DEBUG)
}

// Wrapper for (*Logger).LoadConfiguration
func LoadConfiguration(filename string) {
	Global.LoadConfiguration(filename)
}

// Wrapper for (*Logger).AddFilter
func AddFilter(name string, lvl Level, writer LogWriter) {
	Global.AddFilter(name, lvl, writer)
}

// Wrapper for (*Logger).Close (closes and removes all logwriters)
func Close() {
	Global.Close()
}

func Crash(args ...interface{}) {
	if len(args) > 0 {
		Global.intLogf(CRITICAL, strings.Repeat(" %v", len(args))[1:], args...)
	}
	panic(args)
}

// Logs the given message and crashes the program
func Crashf(format string, args ...interface{}) {
	Global.intLogf(CRITICAL, format, args...)
	Global.Close() // so that hopefully the messages get logged
	panic(fmt.Sprintf(format, args...))
}

// Compatibility with `log`
func Exit(args ...interface{}) {
	if len(args) > 0 {
		Global.intLogf(ERROR, strings.Repeat(" %v", len(args))[1:], args...)
	}
	Global.Close() // so that hopefully the messages get logged
	os.Exit(0)
}

// Compatibility with `log`
func Exitf(format string, args ...interface{}) {
	Global.intLogf(ERROR, format, args...)
	Global.Close() // so that hopefully the messages get logged
	os.Exit(0)
}

// Compatibility with `log`
func Stderr(args ...interface{}) {
	if len(args) > 0 {
		Global.intLogf(ERROR, strings.Repeat(" %v", len(args))[1:], args...)
	}
}

// Compatibility with `log`
func Stderrf(format string, args ...interface{}) {
	Global.intLogf(ERROR, format, args...)
}

// Compatibility with `log`
func Stdout(args ...interface{}) {
	if len(args) > 0 {
		Global.intLogf(INFO, strings.Repeat(" %v", len(args))[1:], args...)
	}
}

// Compatibility with `log`
func Stdoutf(format string, args ...interface{}) {
	Global.intLogf(INFO, format, args...)
}

// Send a log message manually
// Wrapper for (*Logger).Log
func Log(lvl Level, source, message string) {
	Global.Log(lvl, source, message)
}

// Send a formatted log message easily
// Wrapper for (*Logger).Logf
func Logf(lvl Level, format string, args ...interface{}) {
	Global.intLogf(lvl, format, args...)
}

// Send a closure log message
// Wrapper for (*Logger).Logc
func Logc(lvl Level, closure func() string) {
	Global.intLogc(lvl, closure)
}

// Migration support only for Migration ouput
func Migration(level Level, arg0 interface{}, args ...interface{}) {
	var msg string
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		msg = fmt.Sprintf(first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		msg = first()
	default:
		// Build a format string so that it will be similar to Sprint
		msg = fmt.Sprintf(fmt.Sprint(first)+strings.Repeat(" %v", len(args)), args...)
	}

	rec := &LogRecord{
		Level:   level,
		Created: time.Now(),
		Source:  "Migration",
		Message: msg,
	}
	for _, filt := range Global {
		filt.LogWrite(rec)
	}
}

// Utility for finest log messages (see Debug() for parameter explanation)
// Wrapper for (*Logger).Finest
func Finest(arg0 interface{}, args ...interface{}) {
	const (
		lvl = FINEST
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		Global.intLogc(lvl, first)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(arg0)+strings.Repeat(" %v", len(args)), args...)
	}
}

// Utility for fine log messages (see Debug() for parameter explanation)
// Wrapper for (*Logger).Fine
func Fine(arg0 interface{}, args ...interface{}) {
	const (
		lvl = FINE
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		Global.intLogc(lvl, first)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(arg0)+strings.Repeat(" %v", len(args)), args...)
	}
}

// Utility for debug log messages
// When given a string as the first argument, this behaves like Logf but with the DEBUG log level (e.g. the first argument is interpreted as a format for the latter arguments)
// When given a closure of type func()string, this logs the string returned by the closure iff it will be logged.  The closure runs at most one time.
// When given anything else, the log message will be each of the arguments formatted with %v and separated by spaces (ala Sprint).
// Wrapper for (*Logger).Debug
func Debug(arg0 interface{}, args ...interface{}) {
	const (
		lvl = DEBUG
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		Global.intLogc(lvl, first)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(arg0)+strings.Repeat(" %v", len(args)), args...)
	}
}

// Utility for trace log messages (see Debug() for parameter explanation)
// Wrapper for (*Logger).Trace
func Trace(arg0 interface{}, args ...interface{}) {
	const (
		lvl = TRACE
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		Global.intLogc(lvl, first)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(arg0)+strings.Repeat(" %v", len(args)), args...)
	}
}

// Utility for info log messages (see Debug() for parameter explanation)
// Wrapper for (*Logger).Info
func Info(arg0 interface{}, args ...interface{}) {
	const (
		lvl = INFO
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
	case func() string:
		// Log the closure (no other arguments used)
		Global.intLogc(lvl, first)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(arg0)+strings.Repeat(" %v", len(args)), args...)
	}
}

// Utility for warn log messages (returns an error for easy function returns) (see Debug() for parameter explanation)
// These functions will execute a closure exactly once, to build the error message for the return
// Wrapper for (*Logger).Warn
func Warn(arg0 interface{}, args ...interface{}) error {
	const (
		lvl = WARNING
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
		return errors.New(fmt.Sprintf(first, args...))
	case func() string:
		// Log the closure (no other arguments used)
		str := first()
		Global.intLogf(lvl, "%s", str)
		return errors.New(str)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(first)+strings.Repeat(" %v", len(args)), args...)
		return errors.New(fmt.Sprint(first) + fmt.Sprintf(strings.Repeat(" %v", len(args)), args...))
	}
	return nil
}

// Utility for error log messages (returns an error for easy function returns) (see Debug() for parameter explanation)
// These functions will execute a closure exactly once, to build the error message for the return
// Wrapper for (*Logger).Error
func Error(arg0 interface{}, args ...interface{}) error {
	const (
		lvl = ERROR
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
		return errors.New(fmt.Sprintf(first, args...))
	case func() string:
		// Log the closure (no other arguments used)
		str := first()
		Global.intLogf(lvl, "%s", str)
		return errors.New(str)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(first)+strings.Repeat(" %v", len(args)), args...)
		return errors.New(fmt.Sprint(first) + fmt.Sprintf(strings.Repeat(" %v", len(args)), args...))
	}
	return nil
}

// Utility for critical log messages (returns an error for easy function returns) (see Debug() for parameter explanation)
// These functions will execute a closure exactly once, to build the error message for the return
// Wrapper for (*Logger).Critical
func Critical(arg0 interface{}, args ...interface{}) error {
	const (
		lvl = CRITICAL
	)
	switch first := arg0.(type) {
	case string:
		// Use the string as a format string
		Global.intLogf(lvl, first, args...)
		return errors.New(fmt.Sprintf(first, args...))
	case func() string:
		// Log the closure (no other arguments used)
		str := first()
		Global.intLogf(lvl, "%s", str)
		return errors.New(str)
	default:
		// Build a format string so that it will be similar to Sprint
		Global.intLogf(lvl, fmt.Sprint(first)+strings.Repeat(" %v", len(args)), args...)
		return errors.New(fmt.Sprint(first) + fmt.Sprintf(strings.Repeat(" %v", len(args)), args...))
	}
	return nil
}

// wrapWriter returns a proxy that wraps ResponseWriter
func wrapWriter(w http.ResponseWriter) writerProxy {
	bw := basicWriter{ResponseWriter: w}
	return &bw
}

// writerProxy is a proxy that wraps ResponseWriter
type writerProxy interface {
	http.ResponseWriter
	maybeWriteHeader()
	status() int
}

// basicWriter holds the status code and a
// flag in addition to http.ResponseWriter
type basicWriter struct {
	http.ResponseWriter
	wroteHeader bool
	code        int
}

// WriteHeader stores the status code and writes header
func (b *basicWriter) WriteHeader(code int) {
	if !b.wroteHeader {
		b.code = code
		b.wroteHeader = true
		b.ResponseWriter.WriteHeader(code)
	}
}

// Write writes the bytes and calls MaybeWriteHeader
func (b *basicWriter) Write(buf []byte) (int, error) {
	b.maybeWriteHeader()
	return b.ResponseWriter.Write(buf)
}

// maybeWriteHeader writes the header if it is not alredy set
func (b *basicWriter) maybeWriteHeader() {
	if !b.wroteHeader {
		b.WriteHeader(http.StatusOK)
	}
}

// status returns the status
func (b *basicWriter) status() int {
	return b.code
}

// unwrap returns the original http.ResponseWriter
func (b *basicWriter) Unwrap() http.ResponseWriter {
	return b.ResponseWriter
}