lbcd/log.go
2014-05-07 11:14:39 -05:00

75 lines
2 KiB
Go

// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcrpcclient
import (
"errors"
"github.com/conformal/btclog"
"io"
)
// log is a logger that is initialized with no output filters. This
// means the package will not perform any logging by default until the caller
// requests it.
var log btclog.Logger
// The default amount of logging is none.
func init() {
DisableLog()
}
// DisableLog disables all library log output. Logging output is disabled
// by default until either UseLogger or SetLogWriter are called.
func DisableLog() {
log = btclog.Disabled
}
// UseLogger uses a specified Logger to output package logging info.
// This should be used in preference to SetLogWriter if the caller is also
// using btclog.
func UseLogger(logger btclog.Logger) {
log = logger
}
// SetLogWriter uses a specified io.Writer to output package logging info.
// This allows a caller to direct package logging output without needing a
// dependency on seelog. If the caller is also using btclog, UseLogger should
// be used instead.
func SetLogWriter(w io.Writer, level string) error {
if w == nil {
return errors.New("nil writer")
}
lvl, ok := btclog.LogLevelFromString(level)
if !ok {
return errors.New("invalid log level")
}
l, err := btclog.NewLoggerFromWriter(w, lvl)
if err != nil {
return err
}
UseLogger(l)
return nil
}
// LogClosure is a closure that can be printed with %v to be used to
// generate expensive-to-create data for a detailed log level and avoid doing
// the work if the data isn't printed.
type logClosure func() string
// String invokes the log closure and returns the results string.
func (c logClosure) String() string {
return c()
}
// newLogClosure returns a new closure over the passed function which allows
// it to be used as a parameter in a logging function that is only invoked when
// the logging level is such that the message will actually be logged.
func newLogClosure(c func() string) logClosure {
return logClosure(c)
}