• Rob Pike's avatar
    log: new interface · 12da5a90
    Rob Pike authored
    New logging interface simplifies and generalizes.
    
    1) Loggers now have only one output.
    2) log.Stdout, Stderr, Crash and friends are gone.
    	Logging is now always to standard error by default.
    3) log.Panic* replaces log.Crash*.
    4) Exiting and panicking are not part of the logger's state; instead
    	the functions Exit* and Panic* simply call Exit or panic after
    	printing.
    5) There is now one 'standard logger'.  Instead of calling Stderr,
    	use Print etc.  There are now triples, by analogy with fmt:
    		Print, Println, Printf
    	What was log.Stderr is now best represented by log.Println,
    	since there are now separate Print and Println functions
    	(and methods).
    6) New functions SetOutput, SetFlags, and SetPrefix allow global
    	editing of the standard logger's properties.   This is new
    	functionality. For instance, one can call
    		log.SetFlags(log.Lshortfile|log.Ltime|log.Lmicroseconds)
    	to get all logging output to show file name, line number, and
    	time stamp.
    
    In short, for most purposes
    	log.Stderr -> log.Println or log.Print
    	log.Stderrf -> log.Printf
    	log.Crash -> log.Panicln or log.Panic
    	log.Crashf -> log.Panicf
    	log.Exit -> log.Exitln or log.Exit
    	log.Exitf -> log.Exitf (no change)
    
    This has a slight breakage: since loggers now write only to one
    output, existing calls to log.New() need to delete the second argument.
    Also, custom loggers with exit or panic properties will need to be
    reworked.
    
    All package code updated to new interface.
    
    The test has been reworked somewhat.
    
    The old interface will be removed after the new release.
    For now, its elements are marked 'deprecated' in their comments.
    
    Fixes #1184.
    
    R=rsc
    CC=golang-dev
    https://golang.org/cl/2419042
    12da5a90
vars.go 6.78 KB