log4go: github.com/alecthomas/log4go Index | Files | Directories

package log4go

import "github.com/alecthomas/log4go"

Package log4go provides level-based and highly configurable logging.

Enhanced Logging

This is inspired by the logging functionality in Java. Essentially, you create a Logger object and create output filters for it. You can send whatever you want to the Logger, and it will filter that based on your settings and send it to the outputs. This way, you can put as much debug code in your program as you want, and when you're done you can filter out the mundane messages so only the important ones show up.

Utility functions are provided to make life easier. Here is some example code to get started:

log := log4go.NewLogger() log.AddFilter("stdout", log4go.DEBUG, log4go.NewConsoleLogWriter()) log.AddFilter("log", log4go.FINE, log4go.NewFileLogWriter("example.log", true)) log.Info("The time is now: %s", time.LocalTime().Format("15:04:05 MST 2006/01/02"))

The first two lines can be combined with the utility NewDefaultLogger:

log := log4go.NewDefaultLogger(log4go.DEBUG) log.AddFilter("log", log4go.FINE, log4go.NewFileLogWriter("example.log", true)) log.Info("The time is now: %s", time.LocalTime().Format("15:04:05 MST 2006/01/02"))

Usage notes: - The ConsoleLogWriter does not display the source of the message to standard

output, but the FileLogWriter does.

- The utility functions (Info, Debug, Warn, etc) derive their source from the

calling function, and this incurs extra overhead.

Changes from 2.0: - The external interface has remained mostly stable, but a lot of the

internals have been changed, so if you depended on any of this or created
your own LogWriter, then you will probably have to update your code.  In
particular, Logger is now a map and ConsoleLogWriter is now a channel
behind-the-scenes, and the LogWrite method no longer has return values.

Future work: (please let me know if you think I should work on any of these particularly) - Log file rotation - Logging configuration files ala log4j - Have the ability to remove filters? - Have GetInfoChannel, GetDebugChannel, etc return a chan string that allows

for another method of logging

- Add an XML filter type

Index

Package Files

config.go filelog.go log4go.go pattlog.go socklog.go termlog.go wrapper.go

Constants

const (
    L4G_VERSION = "log4go-v3.0.1"
    L4G_MAJOR   = 3
    L4G_MINOR   = 0
    L4G_BUILD   = 1
)

Version information

const (
    FORMAT_DEFAULT = "[%D %T] [%L] (%S) %M"
    FORMAT_SHORT   = "[%t %d] [%L] %M"
    FORMAT_ABBREV  = "[%L] %M"
)

Variables

var (
    // LogBufferLength specifies how many log messages a particular log4go
    // logger can buffer at a time before writing them.
    LogBufferLength = 32
)

***** Variables *****

func AddFilter Uses

func AddFilter(name string, lvl Level, writer LogWriter)

Wrapper for (*Logger).AddFilter

func Close Uses

func Close()

Wrapper for (*Logger).Close (closes and removes all logwriters)

func Crash Uses

func Crash(args ...interface{})

func Crashf Uses

func Crashf(format string, args ...interface{})

Logs the given message and crashes the program

func Critical Uses

func Critical(arg0 interface{}, args ...interface{}) error

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 Debug Uses

func Debug(arg0 interface{}, args ...interface{})

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 Error Uses

func Error(arg0 interface{}, args ...interface{}) error

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 Exit Uses

func Exit(args ...interface{})

Compatibility with `log`

func Exitf Uses

func Exitf(format string, args ...interface{})

Compatibility with `log`

func Fine Uses

func Fine(arg0 interface{}, args ...interface{})

Utility for fine log messages (see Debug() for parameter explanation) Wrapper for (*Logger).Fine

func Finest Uses

func Finest(arg0 interface{}, args ...interface{})

Utility for finest log messages (see Debug() for parameter explanation) Wrapper for (*Logger).Finest

func FormatLogRecord Uses

func FormatLogRecord(format string, rec *LogRecord) string

Known format codes: %T - Time (15:04:05 MST) %t - Time (15:04) %D - Date (2006/01/02) %d - Date (01/02/06) %L - Level (FNST, FINE, DEBG, TRAC, WARN, EROR, CRIT) %S - Source %M - Message Ignores unknown formats Recommended: "[%D %T] [%L] (%S) %M"

func Info Uses

func Info(arg0 interface{}, args ...interface{})

Utility for info log messages (see Debug() for parameter explanation) Wrapper for (*Logger).Info

func LoadConfiguration Uses

func LoadConfiguration(filename string)

Wrapper for (*Logger).LoadConfiguration

func Log Uses

func Log(lvl Level, source, message string)

Send a log message manually Wrapper for (*Logger).Log

func Logc Uses

func Logc(lvl Level, closure func() string)

Send a closure log message Wrapper for (*Logger).Logc

func Logf Uses

func Logf(lvl Level, format string, args ...interface{})

Send a formatted log message easily Wrapper for (*Logger).Logf

func Stderr Uses

func Stderr(args ...interface{})

Compatibility with `log`

func Stderrf Uses

func Stderrf(format string, args ...interface{})

Compatibility with `log`

func Stdout Uses

func Stdout(args ...interface{})

Compatibility with `log`

func Stdoutf Uses

func Stdoutf(format string, args ...interface{})

Compatibility with `log`

func Trace Uses

func Trace(arg0 interface{}, args ...interface{})

Utility for trace log messages (see Debug() for parameter explanation) Wrapper for (*Logger).Trace

func Warn Uses

func Warn(arg0 interface{}, args ...interface{}) error

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

type ConsoleLogWriter Uses

type ConsoleLogWriter struct {
    // contains filtered or unexported fields
}

This is the standard writer that prints to standard output.

func NewConsoleLogWriter Uses

func NewConsoleLogWriter() *ConsoleLogWriter

This creates a new ConsoleLogWriter

func (*ConsoleLogWriter) Close Uses

func (c *ConsoleLogWriter) Close()

Close stops the logger from sending messages to standard output. Attempts to send log messages to this logger after a Close have undefined behavior.

func (*ConsoleLogWriter) LogWrite Uses

func (c *ConsoleLogWriter) LogWrite(rec *LogRecord)

This is the ConsoleLogWriter's output method. This will block if the output buffer is full.

func (*ConsoleLogWriter) SetFormat Uses

func (c *ConsoleLogWriter) SetFormat(format string)

type FileLogWriter Uses

type FileLogWriter struct {
    // contains filtered or unexported fields
}

This log writer sends output to a file

func NewFileLogWriter Uses

func NewFileLogWriter(fname string, rotate bool) *FileLogWriter

NewFileLogWriter creates a new LogWriter which writes to the given file and has rotation enabled if rotate is true.

If rotate is true, any time a new log file is opened, the old one is renamed with a .### extension to preserve it. The various Set* methods can be used to configure log rotation based on lines, size, and daily.

The standard log-line format is:

[%D %T] [%L] (%S) %M

func NewXMLLogWriter Uses

func NewXMLLogWriter(fname string, rotate bool) *FileLogWriter

NewXMLLogWriter is a utility method for creating a FileLogWriter set up to output XML record log messages instead of line-based ones.

func (*FileLogWriter) Close Uses

func (w *FileLogWriter) Close()

func (*FileLogWriter) LogWrite Uses

func (w *FileLogWriter) LogWrite(rec *LogRecord)

This is the FileLogWriter's output method

func (*FileLogWriter) Rotate Uses

func (w *FileLogWriter) Rotate()

Request that the logs rotate

func (*FileLogWriter) SetFormat Uses

func (w *FileLogWriter) SetFormat(format string) *FileLogWriter

Set the logging format (chainable). Must be called before the first log message is written.

func (*FileLogWriter) SetHeadFoot Uses

func (w *FileLogWriter) SetHeadFoot(head, foot string) *FileLogWriter

Set the logfile header and footer (chainable). Must be called before the first log message is written. These are formatted similar to the FormatLogRecord (e.g. you can use %D and %T in your header/footer for date and time).

func (*FileLogWriter) SetRotate Uses

func (w *FileLogWriter) SetRotate(rotate bool) *FileLogWriter

SetRotate changes whether or not the old logs are kept. (chainable) Must be called before the first log message is written. If rotate is false, the files are overwritten; otherwise, they are rotated to another file before the new log is opened.

func (*FileLogWriter) SetRotateDaily Uses

func (w *FileLogWriter) SetRotateDaily(daily bool) *FileLogWriter

Set rotate daily (chainable). Must be called before the first log message is written.

func (*FileLogWriter) SetRotateLines Uses

func (w *FileLogWriter) SetRotateLines(maxlines int) *FileLogWriter

Set rotate at linecount (chainable). Must be called before the first log message is written.

func (*FileLogWriter) SetRotateMaxBackup Uses

func (w *FileLogWriter) SetRotateMaxBackup(maxbackup int) *FileLogWriter

Set max backup files. Must be called before the first log message is written.

func (*FileLogWriter) SetRotateSize Uses

func (w *FileLogWriter) SetRotateSize(maxsize int) *FileLogWriter

Set rotate at size (chainable). Must be called before the first log message is written.

type Filter Uses

type Filter struct {
    Level Level
    LogWriter
}

A Filter represents the log level below which no log records are written to the associated LogWriter.

type FormatLogWriter Uses

type FormatLogWriter chan *LogRecord

This is the standard writer that prints to standard output.

func NewFormatLogWriter Uses

func NewFormatLogWriter(out io.Writer, format string) FormatLogWriter

This creates a new FormatLogWriter

func (FormatLogWriter) Close Uses

func (w FormatLogWriter) Close()

Close stops the logger from sending messages to standard output. Attempts to send log messages to this logger after a Close have undefined behavior.

func (FormatLogWriter) LogWrite Uses

func (w FormatLogWriter) LogWrite(rec *LogRecord)

This is the FormatLogWriter's output method. This will block if the output buffer is full.

type Level Uses

type Level int

These are the integer logging levels used by the logger

const (
    FINEST Level = iota
    FINE
    DEBUG
    TRACE
    INFO
    WARNING
    ERROR
    CRITICAL
)

func (Level) String Uses

func (l Level) String() string

type LogRecord Uses

type LogRecord struct {
    Level   Level     // The log level
    Created time.Time // The time at which the log message was created (nanoseconds)
    Source  string    // The message source
    Message string    // The log message
}

A LogRecord contains all of the pertinent information for each message

type LogWriter Uses

type LogWriter interface {
    // This will be called to log a LogRecord message.
    LogWrite(rec *LogRecord)

    // This should clean up anything lingering about the LogWriter, as it is called before
    // the LogWriter is removed.  LogWrite should not be called after Close.
    Close()
}

This is an interface for anything that should be able to write logs

type Logger Uses

type Logger map[string]*Filter

A Logger represents a collection of Filters through which log messages are written.

var (
    Global Logger
)

func NewConsoleLogger Uses

func NewConsoleLogger(lvl Level) Logger

Create a new logger with a "stdout" filter configured to send log messages at or above lvl to standard output.

DEPRECATED: use NewDefaultLogger instead.

func NewDefaultLogger Uses

func NewDefaultLogger(lvl Level) Logger

Create a new logger with a "stdout" filter configured to send log messages at or above lvl to standard output.

func NewLogger Uses

func NewLogger() Logger

Create a new logger.

DEPRECATED: Use make(Logger) instead.

func (Logger) AddFilter Uses

func (log Logger) AddFilter(name string, lvl Level, writer LogWriter) Logger

Add a new LogWriter to the Logger which will only log messages at lvl or higher. This function should not be called from multiple goroutines. Returns the logger for chaining.

func (Logger) Close Uses

func (log Logger) Close()

Closes all log writers in preparation for exiting the program or a reconfiguration of logging. Calling this is not really imperative, unless you want to guarantee that all log messages are written. Close removes all filters (and thus all LogWriters) from the logger.

func (Logger) Critical Uses

func (log Logger) Critical(arg0 interface{}, args ...interface{}) error

Critical logs a message at the critical log level and returns the formatted error, See Warn for an explanation of the performance and Debug for an explanation of the parameters.

func (Logger) Debug Uses

func (log Logger) Debug(arg0 interface{}, args ...interface{})

Debug is a utility method for debug log messages. The behavior of Debug depends on the first argument: - arg0 is a string

When given a string as the first argument, this behaves like Logf but with
the DEBUG log level: the first argument is interpreted as a format for the
latter arguments.

- arg0 is a func()string

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.

- arg0 is interface{}

When given anything else, the log message will be each of the arguments
formatted with %v and separated by spaces (ala Sprint).

func (Logger) Error Uses

func (log Logger) Error(arg0 interface{}, args ...interface{}) error

Error logs a message at the error log level and returns the formatted error, See Warn for an explanation of the performance and Debug for an explanation of the parameters.

func (Logger) Fine Uses

func (log Logger) Fine(arg0 interface{}, args ...interface{})

Fine logs a message at the fine log level. See Debug for an explanation of the arguments.

func (Logger) Finest Uses

func (log Logger) Finest(arg0 interface{}, args ...interface{})

Finest logs a message at the finest log level. See Debug for an explanation of the arguments.

func (Logger) Info Uses

func (log Logger) Info(arg0 interface{}, args ...interface{})

Info logs a message at the info log level. See Debug for an explanation of the arguments.

func (Logger) LoadConfiguration Uses

func (log Logger) LoadConfiguration(filename string)

Load XML configuration; see examples/example.xml for documentation

func (Logger) Log Uses

func (log Logger) Log(lvl Level, source, message string)

Send a log message with manual level, source, and message.

func (Logger) Logc Uses

func (log Logger) Logc(lvl Level, closure func() string)

Logc logs a string returned by the closure at the given log level, using the caller as its source. If no log message would be written, the closure is never called.

func (Logger) Logf Uses

func (log Logger) Logf(lvl Level, format string, args ...interface{})

Logf logs a formatted log message at the given log level, using the caller as its source.

func (Logger) Trace Uses

func (log Logger) Trace(arg0 interface{}, args ...interface{})

Trace logs a message at the trace log level. See Debug for an explanation of the arguments.

func (Logger) Warn Uses

func (log Logger) Warn(arg0 interface{}, args ...interface{}) error

Warn logs a message at the warning log level and returns the formatted error. At the warning level and higher, there is no performance benefit if the message is not actually logged, because all formats are processed and all closures are executed to format the error message. See Debug for further explanation of the arguments.

type SocketLogWriter Uses

type SocketLogWriter chan *LogRecord

This log writer sends output to a socket

func NewSocketLogWriter Uses

func NewSocketLogWriter(proto, hostport string) SocketLogWriter

func (SocketLogWriter) Close Uses

func (w SocketLogWriter) Close()

func (SocketLogWriter) LogWrite Uses

func (w SocketLogWriter) LogWrite(rec *LogRecord)

This is the SocketLogWriter's output method

Directories

PathSynopsis
examples

Package log4go imports 14 packages (graph) and is imported by 272 packages. Updated 2018-06-06. Refresh now. Tools for package owners.