Implement Logger (#228)

* Added new base logger

* updated example and test configs

* updated exchange helpers restful router & server

* logPath is now passed to the logger to remove dependency on common package

* updated everything besides exchanges to use new logger

* alphapoint to bitmex done

* updated bitmex bitstamp bittrex btcc and also performance changes to logger

* btcmarkets coinbase coinut exmo gateio wrappers updated

* gateio and gemini logger updated

* hitbtc huobi itbit & kraken updated

* All exchanges updatd

* return correct error for disabled websocket

* don't disconnect client on invalid json

* updated router internal logging

* log.Fatal to t.Error for tests

* Changed from fatal to error failure to set maxprocs

* output ANSI codes for everything but windows for now due to lack of windows support

* added error handling to logger and unit tests

* clear wording on print -> log.print

* added benchmark test

* cleaned up import sections

* Updated logger based on PR requests (added default config options on failure/setting errors)

* ah this should fix travici enc config issue

* Load entire config and clear out logging to hopefully fix travisci issue

* wording & test error handling

* fixed formatting issues based on feedback

* fixed formatting issues based on feedback

* changed CheckDir to use mkdirall instead of mkdir and other changes based on feedback

logger/logger.go

@@ -0,0 +1,120 @@
+package logger
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+	"runtime"
+	"time"
+)
+
+func init() {
+	setDefaultOutputs()
+}
+
+// SetupLogger configure logger instance with user provided settings
+func SetupLogger() (err error) {
+	if *Logger.Enabled {
+		err = setupOutputs()
+		if err != nil {
+			return
+		}
+		logLevel()
+		if Logger.ColourOutput {
+			colourOutput()
+		}
+	} else {
+		clearAllLoggers()
+	}
+	return
+}
+
+// setDefaultOutputs() this setups defaults used by the logger
+// This allows it to be used without any user configuration
+func setDefaultOutputs() {
+	debugLogger = log.New(os.Stdout,
+		"[DEBUG]: ",
+		log.Ldate|log.Ltime)
+
+	infoLogger = log.New(os.Stdout,
+		"[INFO]: ",
+		log.Ldate|log.Ltime)
+
+	warnLogger = log.New(os.Stdout,
+		"[WARN]: ",
+		log.Ldate|log.Ltime)
+
+	errorLogger = log.New(os.Stdout,
+		"[ERROR]: ",
+		log.Ldate|log.Ltime)
+
+	fatalLogger = log.New(os.Stdout,
+		"[FATAL]: ",
+		log.Ldate|log.Ltime)
+}
+
+// colorOutput() sets the prefix of each log type to matching colour
+// TODO: add windows support
+func colourOutput() {
+	if runtime.GOOS != "windows" {
+		debugLogger.SetPrefix("\033[34m[DEBUG]\033[0m: ")
+		infoLogger.SetPrefix("\033[32m[INFO]\033[0m: ")
+		warnLogger.SetPrefix("\033[33m[WARN]\033[0m: ")
+		errorLogger.SetPrefix("\033[31m[ERROR]\033[0m: ")
+		fatalLogger.SetPrefix("\033[31m[FATAL]\033[0m: ")
+	}
+}
+
+// clearAllLoggers() sets all logger flags to 0 and outputs to Discard
+func clearAllLoggers() {
+	debugLogger.SetFlags(0)
+	infoLogger.SetFlags(0)
+	warnLogger.SetFlags(0)
+	errorLogger.SetFlags(0)
+	fatalLogger.SetFlags(0)
+
+	debugLogger.SetOutput(ioutil.Discard)
+	infoLogger.SetOutput(ioutil.Discard)
+	warnLogger.SetOutput(ioutil.Discard)
+	errorLogger.SetOutput(ioutil.Discard)
+	fatalLogger.SetOutput(ioutil.Discard)
+}
+
+// setupOutputs() sets up the io.writer to use for logging
+// TODO: Fix up rotating at the moment its a quick job
+func setupOutputs() (err error) {
+	if len(Logger.File) > 0 {
+		logFile := path.Join(LogPath, Logger.File)
+		if Logger.Rotate {
+			if _, err = os.Stat(logFile); !os.IsNotExist(err) {
+				currentTime := time.Now()
+				newName := currentTime.Format("2006-01-02 15-04-05")
+				newFile := newName + " " + Logger.File
+				err = os.Rename(logFile, path.Join(LogPath, newFile))
+				if err != nil {
+					err = fmt.Errorf("Failed to rename old log file %s", err)
+					return
+				}
+			}
+		}
+		logFileHandle, err = os.OpenFile(logFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+		if err != nil {
+			return
+		}
+		logOutput = io.MultiWriter(os.Stdout, logFileHandle)
+	} else {
+		logOutput = os.Stdout
+	}
+	return
+}
+
+// CloseLogFile close the handler for any open log files
+func CloseLogFile() (err error) {
+	if logFileHandle != nil {
+		err = logFileHandle.Close()
+	}
+	return
+}