Merge pull request #522 from abperiasamy/console

simple console

console.go

@@ -0,0 +1,163 @@
+/*
+ * Mini Copy (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"sync"
+
+	"path/filepath"
+)
+
+type logLevel int
+
+const (
+	levelUnknown logLevel = iota
+	levelDebug
+	levelInfo
+	levelError
+	levelFatal
+)
+
+var (
+	mutex = &sync.RWMutex{}
+
+	// Fatal prints a error message and exits
+	Fatal = func(a ...interface{}) { privatePrint(levelFatal, a...) }
+	// Fatalln prints a error message with a new line and exits
+	Fatalln = func(a ...interface{}) { privatePrintln(levelFatal, a...) }
+	// Fatalf prints a error message with formatting and exits
+	Fatalf = func(f string, a ...interface{}) { privatePrintf(levelFatal, f, a...) }
+
+	// Error prints a error message
+	Error = func(a ...interface{}) { privatePrint(levelError, a...) }
+	// Errorln prints a error message with a new line
+	Errorln = func(a ...interface{}) { privatePrintln(levelError, a...) }
+	// Errorf prints a error message with formatting
+	Errorf = func(f string, a ...interface{}) { privatePrintf(levelError, f, a...) }
+
+	// Info prints a informational message
+	Info = func(a ...interface{}) { privatePrint(levelInfo, a...) }
+	// Infoln prints a informational message with a new line
+	Infoln = func(a ...interface{}) { privatePrintln(levelInfo, a...) }
+	// Infof prints a informational message with formatting
+	Infof = func(f string, a ...interface{}) { privatePrintf(levelInfo, f, a...) }
+
+	// Debug prints a debug message
+	Debug = func(a ...interface{}) { privatePrint(levelDebug, a...) }
+	// Debugln prints a debug message with a new line
+	Debugln = func(a ...interface{}) { privatePrintln(levelDebug, a...) }
+	// Debugf prints a debug message with formatting
+	Debugf = func(f string, a ...interface{}) { privatePrintf(levelDebug, f, a...) }
+)
+
+var (
+	// print prints a message prefixed with message type and program name
+	privatePrint = func(l logLevel, a ...interface{}) {
+		switch l {
+		case levelDebug:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <DEBUG> ")
+			fmt.Fprint(os.Stderr, a...)
+			mutex.Unlock()
+		case levelInfo:
+			mutex.Lock()
+			fmt.Print(ProgramName() + ": <INFO> ")
+			fmt.Print(a...)
+			mutex.Unlock()
+		case levelError:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <ERROR> ")
+			fmt.Fprint(os.Stderr, a...)
+			mutex.Unlock()
+		case levelFatal:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <FATAL> ")
+			fmt.Fprint(os.Stderr, a...)
+			mutex.Unlock()
+			os.Exit(1)
+		default:
+			fmt.Print(a...)
+		}
+	}
+
+	// println - same as print with a new line
+	privatePrintln = func(l logLevel, a ...interface{}) {
+		switch l {
+		case levelDebug:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <DEBUG> ")
+			fmt.Fprintln(os.Stderr, a...)
+			mutex.Unlock()
+		case levelInfo:
+			mutex.Lock()
+			fmt.Print(ProgramName() + ": <INFO> ")
+			fmt.Println(a...)
+			mutex.Unlock()
+		case levelError:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <ERROR> ")
+			fmt.Fprintln(os.Stderr, a...)
+			mutex.Unlock()
+		case levelFatal:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <FATAL> ")
+			fmt.Fprintln(os.Stderr, a...)
+			mutex.Unlock()
+			os.Exit(1)
+		default:
+			fmt.Print(a...)
+		}
+	}
+
+	// printf - same as print, but takes a format specifier
+	privatePrintf = func(l logLevel, f string, a ...interface{}) {
+		switch l {
+		case levelDebug:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <DEBUG> ")
+			fmt.Fprintf(os.Stderr, f, a...)
+			mutex.Unlock()
+		case levelInfo:
+			mutex.Lock()
+			fmt.Print(ProgramName() + ": <INFO> ")
+			fmt.Printf(f, a...)
+			mutex.Unlock()
+		case levelError:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <ERROR> ")
+			fmt.Fprintf(os.Stderr, f, a...)
+			mutex.Unlock()
+
+		case levelFatal:
+			mutex.Lock()
+			fmt.Fprint(os.Stderr, ProgramName()+": <FATAL> ")
+			fmt.Fprintf(os.Stderr, f, a...)
+			mutex.Unlock()
+			os.Exit(1)
+		default:
+			fmt.Printf(f, a...)
+		}
+	}
+)
+
+// ProgramName - return the name of the executable program
+func ProgramName() string {
+	_, progName := filepath.Split(os.Args[0])
+	return progName
+}