Documentation
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Overview ¶
Package glog implements logging analogous to the Google-internal C++ INFO/ERROR/V setup. It provides functions Info, Warning, Error, Fatal, plus formatting variants such as Infof. It also provides V-style logging controlled by the -v and -vmodule=file=2 flags.
Basic examples:
glog.Info("Prepare to repel boarders")
glog.Fatalf("Initialization failed: %s", err)
See the documentation for the V function for an explanation of these examples:
if glog.V(2) {
glog.Info("Starting transaction...")
}
glog.V(2).Infoln("Processed", nItems, "elements")
Log output is buffered and written periodically using Flush. Programs should call Flush before exiting to guarantee all log output is written.
By default, all log statements write to files in a temporary directory. This package provides several flags that modify this behavior. As a result, flag.Parse must be called before any logging is done.
-logtostderr=false Logs are written to standard error instead of to files. -alsologtostderr=false Logs are written to standard error as well as to files. -stderrthreshold=ERROR Log events at or above this severity are logged to standard error as well as to files. -log_dir="" Log files will be written to this directory instead of the default temporary directory.
Other flags provide aids to debugging.
-log_backtrace_at="" A comma-separated list of file and line numbers holding a logging statement, such as -log_backtrace_at=gopherflakes.go:234 A stack trace will be written to the Info log whenever execution hits one of these statements. (Unlike with -vmodule, the ".go" must bepresent.) -v=0 Enable V-leveled logging at the specified level. -vmodule="" The syntax of the argument is a comma-separated list of pattern=N, where pattern is a literal file name (minus the ".go" suffix) or "glob" pattern and N is a V level. For instance, -vmodule=gopher*=3 sets the V level to 3 in all Go files whose names begin with "gopher", and -vmodule=/path/to/glog/glog_test=1 sets the V level to 1 in the Go file /path/to/glog/glog_test.go. If a glob pattern contains a slash, it is matched against the full path, and the file name. Otherwise, the pattern is matched only against the file's basename. When both -vmodule and -v are specified, the -vmodule values take precedence for the specified modules.
Index ¶
- Variables
- func CopyStandardLogTo(name string)
- func Error(args ...any)
- func ErrorDepth(depth int, args ...any)
- func ErrorDepthf(depth int, format string, args ...any)
- func Errorf(format string, args ...any)
- func Errorln(args ...any)
- func ExistPath(path string) bool
- func Exit(args ...any)
- func ExitDepth(depth int, args ...any)
- func ExitDepthf(depth int, format string, args ...any)
- func Exitf(format string, args ...any)
- func Exitln(args ...any)
- func Fatal(args ...any)
- func FatalDepth(depth int, args ...any)
- func FatalDepthf(depth int, format string, args ...any)
- func Fatalf(format string, args ...any)
- func Fatalln(args ...any)
- func Flush()
- func Info(args ...any)
- func InfoDepth(depth int, args ...any)
- func InfoDepthf(depth int, format string, args ...any)
- func Infof(format string, args ...any)
- func Infoln(args ...any)
- func Names(s string) ([]string, error)
- func NewStandardLogger(name string) *stdLog.Logger
- func SetLogPath(path string) error
- func Warning(args ...any)
- func WarningDepth(depth int, args ...any)
- func WarningDepthf(depth int, format string, args ...any)
- func Warningf(format string, args ...any)
- func Warningln(args ...any)
- type Level
- type OutputStats
- type Verbose
Constants ¶
This section is empty.
Variables ¶
var ErrNoLog = errors.New("log file not yet created")
ErrNoLog is the error we return if no log file has yet been created for the specified log type.
var MaxSize uint64 = 1024 * 1024 * 1800
MaxSize is the maximum size of a log file in bytes.
var Stats struct { Info, Warning, Error OutputStats }
Stats tracks the number of lines of output and number of bytes per severity level. Values must be read with atomic.LoadInt64.
Functions ¶
func CopyStandardLogTo ¶
func CopyStandardLogTo(name string)
CopyStandardLogTo arranges for messages written to the Go "log" package's default logs to also appear in the Google logs for the named and lower severities. Subsequent changes to the standard log's default output location or format may break this behavior.
Valid names are "INFO", "WARNING", "ERROR", and "FATAL". If the name is not recognized, CopyStandardLogTo panics.
func Error ¶
func Error(args ...any)
Error logs to the ERROR, WARNING, and INFO logs. Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func ErrorDepth ¶
ErrorDepth acts as Error but uses depth to determine which call frame to log. ErrorDepth(0, "msg") is the same as Error("msg").
func ErrorDepthf ¶
ErrorDepthf acts as Errorf but uses depth to determine which call frame to log. ErrorDepthf(0, "msg") is the same as Errorf("msg").
func Errorf ¶
Errorf logs to the ERROR, WARNING, and INFO logs. Arguments are handled in the manner of fmt.Printf; a newline is appended if missing.
func Errorln ¶
func Errorln(args ...any)
Errorln logs to the ERROR, WARNING, and INFO logs. Arguments are handled in the manner of fmt.Println; a newline is appended if missing.
func Exit ¶
func Exit(args ...any)
Exit logs to the FATAL, ERROR, WARNING, and INFO logs, then calls os.Exit(1). Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func ExitDepth ¶
ExitDepth acts as Exit but uses depth to determine which call frame to log. ExitDepth(0, "msg") is the same as Exit("msg").
func ExitDepthf ¶
ExitDepthf acts as Exitf but uses depth to determine which call frame to log. ExitDepthf(0, "msg") is the same as Exitf("msg").
func Exitf ¶
Exitf logs to the FATAL, ERROR, WARNING, and INFO logs, then calls os.Exit(1). Arguments are handled in the manner of fmt.Printf; a newline is appended if missing.
func Exitln ¶
func Exitln(args ...any)
Exitln logs to the FATAL, ERROR, WARNING, and INFO logs, then calls os.Exit(1).
func Fatal ¶
func Fatal(args ...any)
Fatal logs to the FATAL, ERROR, WARNING, and INFO logs, including a stack trace of all running goroutines, then calls os.Exit(2). Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func FatalDepth ¶
FatalDepth acts as Fatal but uses depth to determine which call frame to log. FatalDepth(0, "msg") is the same as Fatal("msg").
func FatalDepthf ¶
FatalDepthf acts as Fatalf but uses depth to determine which call frame to log. FatalDepthf(0, "msg") is the same as Fatalf("msg").
func Fatalf ¶
Fatalf logs to the FATAL, ERROR, WARNING, and INFO logs, including a stack trace of all running goroutines, then calls os.Exit(2). Arguments are handled in the manner of fmt.Printf; a newline is appended if missing.
func Fatalln ¶
func Fatalln(args ...any)
Fatalln logs to the FATAL, ERROR, WARNING, and INFO logs, including a stack trace of all running goroutines, then calls os.Exit(2). Arguments are handled in the manner of fmt.Println; a newline is appended if missing.
func Info ¶
func Info(args ...any)
Info logs to the INFO log. Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func InfoDepth ¶
InfoDepth calls Info from a different depth in the call stack. This enables a callee to emit logs that use the callsite information of its caller or any other callers in the stack. When depth == 0, the original callee's line information is emitted. When depth > 0, depth frames are skipped in the call stack and the final frame is treated like the original callee to Info.
func InfoDepthf ¶
InfoDepthf acts as InfoDepth but with format string.
func Infof ¶
Infof logs to the INFO log. Arguments are handled in the manner of fmt.Printf; a newline is appended if missing.
func Infoln ¶
func Infoln(args ...any)
Infoln logs to the INFO log. Arguments are handled in the manner of fmt.Println; a newline is appended if missing.
func Names ¶
Names returns the names of the log files holding the FATAL, ERROR, WARNING, or INFO logs. Returns ErrNoLog if the log for the given level doesn't exist (e.g. because no messages of that level have been written). This may return multiple names if the log type requested has rolled over.
func NewStandardLogger ¶
NewStandardLogger returns a Logger that writes to the Google logs for the named and lower severities.
Valid names are "INFO", "WARNING", "ERROR", and "FATAL". If the name is not recognized, NewStandardLogger panics.
func SetLogPath ¶
func Warning ¶
func Warning(args ...any)
Warning logs to the WARNING and INFO logs. Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func WarningDepth ¶
WarningDepth acts as Warning but uses depth to determine which call frame to log. WarningDepth(0, "msg") is the same as Warning("msg").
func WarningDepthf ¶
WarningDepthf acts as Warningf but uses depth to determine which call frame to log. WarningDepthf(0, "msg") is the same as Warningf("msg").
Types ¶
type Level ¶
type Level int32
Level specifies a level of verbosity for V logs. The -v flag is of type Level and should be modified only through the flag.Value interface.
type OutputStats ¶
type OutputStats struct {
// contains filtered or unexported fields
}
OutputStats tracks the number of output lines and bytes written.
func (*OutputStats) Bytes ¶
func (s *OutputStats) Bytes() int64
Bytes returns the number of bytes written.
func (*OutputStats) Lines ¶
func (s *OutputStats) Lines() int64
Lines returns the number of lines written.
type Verbose ¶
type Verbose bool
Verbose is a boolean type that implements Infof (like Printf) etc. See the documentation of V for more information.
func V ¶
V reports whether verbosity at the call site is at least the requested level. The returned value is a boolean of type Verbose, which implements Info, Infoln and Infof. These methods will write to the Info log if called. Thus, one may write either
if glog.V(2) { glog.Info("log this") }
or
glog.V(2).Info("log this")
The second form is shorter but the first is cheaper if logging is off because it does not evaluate its arguments.
Whether an individual call to V generates a log record depends on the setting of the -v and --vmodule flags; both are off by default. If the level in the call to V is at most the value of -v, or of -vmodule for the source file containing the call, the V call will log.
func VDepth ¶
VDepth acts as V but uses depth to determine which call frame to check vmodule for. VDepth(0, level) is the same as V(level).
func (Verbose) Info ¶
Info is equivalent to the global Info function, guarded by the value of v. See the documentation of V for usage.
func (Verbose) InfoDepth ¶
InfoDepth is equivalent to the global InfoDepth function, guarded by the value of v. See the documentation of V for usage.
func (Verbose) InfoDepthf ¶
InfoDepthf is equivalent to the global InfoDepthf function, guarded by the value of v. See the documentation of V for usage.
Source Files