git » log » commit 691f71f

diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..6f1ab52
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,219 @@
+
+Copyright 2016
+
+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.
+
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diff --git a/README.md b/README.md
new file mode 100644
index 0000000..361ea8a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,42 @@
+
+# blitiri.com.ar/go/log
+
+[![GoDoc](https://godoc.org/blitiri.com.ar/go/log?status.svg)](https://godoc.org/blitiri.com.ar/go/log)
+
+[log](https://godoc.org/blitiri.com.ar/go/log) is a Go package implementing a
+simple logger.
+
+It implements an API somewhat similar to [glog](github.com/google/glog), with
+a focus towards simplicity and integration with standard tools such as
+systemd.
+
+
+## Examples
+
+```go
+log.Init()  // only needed once.
+
+log.Debugf("debugging information: %v", x)
+log.Infof("something normal happened")
+log.Errorf("something bad happened")
+log.Fatalf("tragic")
+
+if log.V(3) {  // only entered if -v was >= 3.
+	expensiveDebugging()
+}
+```
+
+
+## Status
+
+The API should be considered stable.
+
+Branch v1 will only have backwards-compatible changes made to it.
+There are no plans for v2 at the moment.
+
+
+## Contact
+
+If you have any questions, comments or patches please send them to
+albertito@blitiri.com.ar.
+
diff --git a/log.go b/log.go
index 7981aab..8632aad 100644
--- a/log.go
+++ b/log.go
@@ -1,13 +1,26 @@
 // Package log implements a simple logger.
 //
 // It implements an API somewhat similar to "github.com/google/glog" with a
-// focus towards logging to stderr, which is useful for systemd-based
-// environments.
+// focus towards simplicity and integration with standard tools such as
+// systemd.
 //
 // There are command line flags (defined using the flag package) to control
 // the behaviour of the default logger. By default, it will write to stderr
 // without timestamps; this is suitable for systemd (or equivalent) logging.
-package log
+//
+// Command-line flags:
+//
+//  -alsologtostderr
+//        also log to stderr, in addition to the file
+//  -logfile string
+//        file to log to (enables logtime)
+//  -logtime
+//        include the time when writing the log to stderr
+//  -logtosyslog string
+//        log to syslog, with the given tag
+//  -v int
+//        verbosity level (1 = debug)
+package log // import "blitiri.com.ar/go/log"
 
 import (
 	"flag"
@@ -25,7 +38,7 @@ import (
 
 // Flags that control the default logging.
 var (
-	vLevel = flag.Int("v", 0, "Verbosity level (1 = debug)")
+	vLevel = flag.Int("v", 0, "verbosity level (1 = debug)")
 
 	logFile = flag.String("logfile", "",
 		"file to log to (enables logtime)")
@@ -40,9 +53,10 @@ var (
 		"also log to stderr, in addition to the file")
 )
 
-// Logging levels.
+// Type of a logging level, to prevent confusion.
 type Level int
 
+// Standard logging levels.
 const (
 	Fatal = Level(-2)
 	Error = Level(-1)
@@ -57,7 +71,7 @@ var levelToLetter = map[Level]string{
 	Debug: ".",
 }
 
-// A Logger represents a logging object that writes logs to the given writer.
+// A Logger represents a logging object that writes logs to a writer.
 type Logger struct {
 	level   Level
 	logTime bool
@@ -68,6 +82,7 @@ type Logger struct {
 	sync.Mutex
 }
 
+// New creates a new Logger, which writes logs to w.
 func New(w io.WriteCloser) *Logger {
 	return &Logger{
 		w:          w,
@@ -77,6 +92,7 @@ func New(w io.WriteCloser) *Logger {
 	}
 }
 
+// NewFile creates a new Logger, which writes logs to the given file.
 func NewFile(path string) (*Logger, error) {
 	f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 	if err != nil {
@@ -88,6 +104,8 @@ func NewFile(path string) (*Logger, error) {
 	return l, nil
 }
 
+// NewSyslog creates a new Logger, which writes logs to syslog, using the
+// given priority and tag.
 func NewSyslog(priority syslog.Priority, tag string) (*Logger, error) {
 	w, err := syslog.New(priority, tag)
 	if err != nil {
@@ -99,14 +117,22 @@ func NewSyslog(priority syslog.Priority, tag string) (*Logger, error) {
 	return l, nil
 }
 
+// Close the writer behind the logger.
 func (l *Logger) Close() {
 	l.w.Close()
 }
 
+// V returns true if the logger's level is >= the one given, false otherwise.
+// It can be used to decide whether to use or gather debugging information
+// only at a certain level, to avoid computing it needlessly.
 func (l *Logger) V(level Level) bool {
 	return level <= l.level
 }
 
+// Log the message into the logger, at the given level. This is low-level and
+// should rarely be needed, but it's available to allow the caller to have
+// more complex logic if needed. skip is the number of frames to skip when
+// computing the file name and line number.
 func (l *Logger) Log(level Level, skip int, format string, a ...interface{}) {
 	if !l.V(level) {
 		return
@@ -147,19 +173,25 @@ func (l *Logger) Log(level Level, skip int, format string, a ...interface{}) {
 	l.Unlock()
 }
 
+// Debugf logs information at a Debug level.
 func (l *Logger) Debugf(format string, a ...interface{}) {
 	l.Log(Debug, 1, format, a...)
 }
 
+// Infof logs information at a Info level.
 func (l *Logger) Infof(format string, a ...interface{}) {
 	l.Log(Info, 1, format, a...)
 }
 
+// Errorf logs information at an Error level. It also returns an error
+// constructed with the given message, in case it's useful for the caller.
 func (l *Logger) Errorf(format string, a ...interface{}) error {
 	l.Log(Error, 1, format, a...)
 	return fmt.Errorf(format, a...)
 }
 
+// Fatalf logs information at a Fatal level, and then exits the program with a
+// non-0 exit code.
 func (l *Logger) Fatalf(format string, a ...interface{}) {
 	l.Log(-2, 1, format, a...)
 	// TODO: Log traceback?
@@ -174,9 +206,9 @@ var Default = &Logger{
 	logTime:    false,
 }
 
-// Init the default logger, based on the command-line flags.
-// Must be called after flag.Parse().
+// Initialize the default logger, based on the command-line flags.
 func Init() {
+	flag.Parse()
 	var err error
 
 	if *logToSyslog != "" {
@@ -201,26 +233,32 @@ func Init() {
 	Default.logTime = *logTime
 }
 
+// V is a convenient wrapper to Default.V.
 func V(level Level) bool {
 	return Default.V(level)
 }
 
+// Log is a convenient wrapper to Default.Log.
 func Log(level Level, skip int, format string, a ...interface{}) {
 	Default.Log(level, skip, format, a...)
 }
 
+// Debugf is a convenient wrapper to Default.Debugf.
 func Debugf(format string, a ...interface{}) {
 	Default.Debugf(format, a...)
 }
 
+// Infof is a convenient wrapper to Default.Infof.
 func Infof(format string, a ...interface{}) {
 	Default.Infof(format, a...)
 }
 
+// Errorf is a convenient wrapper to Default.Errorf.
 func Errorf(format string, a ...interface{}) error {
 	return Default.Errorf(format, a...)
 }
 
+// Fatalf is a convenient wrapper to Default.Fatalf.
 func Fatalf(format string, a ...interface{}) {
 	Default.Fatalf(format, a...)
 }