golog: github.com/mkmueller/golog Index | Examples | Files

package golog

import "github.com/mkmueller/golog"

The golog package is a fork of Go's log package. It is functionally identical to Go's log package which makes it a drop-in replacement with a few added features. The New method is variadic so it can be called using zero to four arguments; the optional fourth argument will set the logging level. The New method accepts a filename as the first argument. Also, the Printf method accepts a logging level parameter.

Index

Examples

Package Files

golog.go golog2.go

Constants

const (
    // Bits or'ed together to control what's printed.
    // There is no control over the order they appear (the order listed
    // here) or the format they present (as described in the comments).
    // The prefix is followed by a colon only when Llongfile or Lshortfile
    // is specified.
    // For example, flags Ldate | Ltime (or LstdFlags) produce,
    //	2009/01/23 01:23:23 message
    // while flags Ldate | Ltime | Lmicroseconds | Llongfile produce,
    //	2009/01/23 01:23:23.123123 /a/b/c/d.go:23: message
    Ldate         = 1 << iota     // the date in the local time zone: 2009/01/23
    Ltime                         // the time in the local time zone: 01:23:23
    Lmicroseconds                 // microsecond resolution: 01:23:23.123123.  assumes Ltime.
    Llongfile                     // full file name and line number: /a/b/c/d.go:23
    Lshortfile                    // final file name element and line number: d.go:23. overrides Llongfile
    LUTC                          // if Ldate or Ltime is set, use UTC rather than the local time zone
    LstdFlags     = Ldate | Ltime // initial values for the standard logger
)

These flags define which text to prefix to each log entry generated by the Logger.

func Fatal Uses

func Fatal(v ...interface{})

Fatal is equivalent to Print() followed by a call to os.Exit(1).

func Fatalf Uses

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

Fatalf is equivalent to Printf() followed by a call to os.Exit(1).

func Fatalln Uses

func Fatalln(v ...interface{})

Fatalln is equivalent to Println() followed by a call to os.Exit(1).

func Flags Uses

func Flags() int

Flags returns the output flags for the standard logger.

func Output Uses

func Output(calldepth int, s string) error

Output writes the output for a logging event. The string s contains the text to print after the prefix specified by the flags of the Logger. A newline is appended if the last character of s is not already a newline. Calldepth is the count of the number of frames to skip when computing the file name and line number if Llongfile or Lshortfile is set; a value of 1 will print the details for the caller of Output.

func Panic Uses

func Panic(v ...interface{})

Panic is equivalent to Print() followed by a call to panic().

func Panicf Uses

func Panicf(format string, v ...interface{})

Panicf is equivalent to Printf() followed by a call to panic().

func Panicln Uses

func Panicln(v ...interface{})

Panicln is equivalent to Println() followed by a call to panic().

func Prefix Uses

func Prefix() string

Prefix returns the output prefix for the standard logger.

func Print Uses

func Print(v ...interface{})

Print calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Print.

func Printf Uses

func Printf(format string, v ...interface{})

Printf calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Printf.

func Println Uses

func Println(v ...interface{})

Println calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Println.

func SetFlags Uses

func SetFlags(flag int)

SetFlags sets the output flags for the standard logger.

func SetOutput Uses

func SetOutput(w io.Writer)

SetOutput sets the output destination for the standard logger.

func SetPrefix Uses

func SetPrefix(prefix string)

SetPrefix sets the output prefix for the standard logger.

type Logger Uses

type Logger struct {
    Err      error       // Set if an error was encountered during file opening
    Filename string      // Output filename
    FileMode os.FileMode // Permissions of output file. Default is 0660
    Options  int         // Output file flags. Default is os.O_WRONLY|os.O_CREATE|os.O_APPEND
    // contains filtered or unexported fields
}

Code:

var (
    buf    bytes.Buffer
    logger = New(&buf, "logger: ", Lshortfile)
)

logger.Print("Hello, log file!")

fmt.Print(&buf)

Output:

logger: example_test.go:19: Hello, log file!

func New Uses

func New(v ...interface{}) *Logger

New creates a new Logger. Similar in usage to the New function in Go's log package, it may be called in a similar way using out, prefix and flag arguments. However, you may also call it using no arguments at all in which case the default output will be stderr, no prefix, and the flag set to 0. Being a variadic function, New will allow one, two, three or four arguments. The first argument may be a string filename or an io.Writer like *os.File or *bytes.Buffer. An optional fourth argument will set the logging level for the Printf method. When a filename is passed as the first argument, the flags will automatically be set to Ldate | Ltime.

The following argument combinations may be used with the New method:

golog.New()
golog.New(flags)
golog.New(flags, prefix)
golog.New(out, prefix, flags)
golog.New(file)
golog.New(file, flags)
golog.New(file, prefix, flags)
golog.New(file, prefix, flags, level)

Create a new logger using no arguments. Output to stderr by default.

Code:


logger := New()
logger.Printf("Hello stderr")
// outputs: Hello stderr

logger = New("/tmp/mylog.log")
logger.Printf("Hello file")
// outputs to file: 2017-11-11 01:23:45 Hello file

func (*Logger) Fatal Uses

func (l *Logger) Fatal(v ...interface{})

Fatal is equivalent to l.Print() followed by a call to os.Exit(1).

func (*Logger) Fatalf Uses

func (l *Logger) Fatalf(format string, v ...interface{})

Fatalf is equivalent to l.Printf() followed by a call to os.Exit(1).

func (*Logger) Fatalln Uses

func (l *Logger) Fatalln(v ...interface{})

Fatalln is equivalent to l.Println() followed by a call to os.Exit(1).

func (*Logger) Flags Uses

func (l *Logger) Flags() int

Flags returns the output flags for the logger.

func (*Logger) Output Uses

func (l *Logger) Output(calldepth int, s string) error

Output writes the output for a logging event. The string s contains the text to print after the prefix specified by the flags of the Logger. A newline is appended if the last character of s is not already a newline. Calldepth is used to recover the PC and is provided for generality, although at the moment on all pre-defined paths it will be 2. Output will be written to a file if a filename was supplied in the New or SetOutput methods. If the file cannot be opened, output will be sent to stderr instead and logger.Err value will be set.

Code:

var (
    buf    bytes.Buffer
    logger = New(&buf, "INFO: ", Lshortfile)

    infof = func(info string) {
        logger.Output(2, info)
    }
)

infof("Hello world")

fmt.Print(&buf)

Output:

INFO: example_test.go:36: Hello world

func (*Logger) Panic Uses

func (l *Logger) Panic(v ...interface{})

Panic is equivalent to l.Print() followed by a call to panic().

func (*Logger) Panicf Uses

func (l *Logger) Panicf(format string, v ...interface{})

Panicf is equivalent to l.Printf() followed by a call to panic().

func (*Logger) Panicln Uses

func (l *Logger) Panicln(v ...interface{})

Panicln is equivalent to l.Println() followed by a call to panic().

func (*Logger) Prefix Uses

func (l *Logger) Prefix() string

Prefix returns the output prefix for the logger.

func (*Logger) Print Uses

func (l *Logger) Print(v ...interface{})

Print calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Print.

func (*Logger) Printf Uses

func (l *Logger) Printf(format string, v ...interface{})

Printf calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Printf. If the format string "%LVL" is used in combination with an integer as the first value, the output level will be checked. Output will proceed only if the supplied level is less than or equal to the configured logging level.

Print only level 2 and lower messages.

Code:

var buf bytes.Buffer
logger := New(&buf, Lshortfile)
logger.SetLevel(2)

logger.Printf("%LVL: Zero", 0)
logger.Printf("%LVL: One", 1)
logger.Printf("%LVL: Two", 2)
logger.Printf("%LVL: Three", 3)

fmt.Print(&buf)

Output:

example_test.go:51: 0: Zero
example_test.go:52: 1: One
example_test.go:53: 2: Two

func (*Logger) Println Uses

func (l *Logger) Println(v ...interface{})

Println calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Println.

func (*Logger) SetFlags Uses

func (l *Logger) SetFlags(flag int)

SetFlags sets the output flags for the logger.

func (*Logger) SetLevel Uses

func (l *Logger) SetLevel(n int)

SetLevel will set the output logging level for the Printf method. The default logging level is -1 causing all levels to be output. Setting the level to any value greater than -1 will allow all levels up to and including that level to be output. For example, setting the level to 9 will allow Printf levels 0 - 9 to be output.

func (*Logger) SetOutput Uses

func (l *Logger) SetOutput(v interface{})

SetOutput sets the output destination for the logger. The argument may be an io.Writer or a filename string. If a string is supplied, the file is opened then immediately closed which will create an empty file if it does not already exist. If an error is encountered during file opening, the output will be set to stderr and the logger Err value will be set.

func (*Logger) SetPrefix Uses

func (l *Logger) SetPrefix(prefix string)

SetPrefix sets the output prefix for the logger.

Package golog imports 8 packages (graph). Updated 2017-11-12. Refresh now. Tools for package owners.