Merge pull request #3696 from karalabe/contextual-logger

Contextual logger

1 files changed, 57 insertions, 0 deletions

diff --git a/log/syslog.go b/log/syslog.go
new file mode 100644
index 000000000..71a17b30b
--- /dev/null
+++ b/log/syslog.go
@@ -0,0 +1,57 @@
+// +build !windows,!plan9
+
+package log
+
+import (
+	"log/syslog"
+	"strings"
+)
+
+// SyslogHandler opens a connection to the system syslog daemon by calling
+// syslog.New and writes all records to it.
+func SyslogHandler(priority syslog.Priority, tag string, fmtr Format) (Handler, error) {
+	wr, err := syslog.New(priority, tag)
+	return sharedSyslog(fmtr, wr, err)
+}
+
+// SyslogNetHandler opens a connection to a log daemon over the network and writes
+// all log records to it.
+func SyslogNetHandler(net, addr string, priority syslog.Priority, tag string, fmtr Format) (Handler, error) {
+	wr, err := syslog.Dial(net, addr, priority, tag)
+	return sharedSyslog(fmtr, wr, err)
+}
+
+func sharedSyslog(fmtr Format, sysWr *syslog.Writer, err error) (Handler, error) {
+	if err != nil {
+		return nil, err
+	}
+	h := FuncHandler(func(r *Record) error {
+		var syslogFn = sysWr.Info
+		switch r.Lvl {
+		case LvlCrit:
+			syslogFn = sysWr.Crit
+		case LvlError:
+			syslogFn = sysWr.Err
+		case LvlWarn:
+			syslogFn = sysWr.Warning
+		case LvlInfo:
+			syslogFn = sysWr.Info
+		case LvlDebug:
+			syslogFn = sysWr.Debug
+		case LvlTrace:
+			syslogFn = func(m string) error { return nil } // There's no syslog level for trace
+		}
+
+		s := strings.TrimSpace(string(fmtr.Format(r)))
+		return syslogFn(s)
+	})
+	return LazyHandler(&closingHandler{sysWr, h}), nil
+}
+
+func (m muster) SyslogHandler(priority syslog.Priority, tag string, fmtr Format) Handler {
+	return must(SyslogHandler(priority, tag, fmtr))
+}
+
+func (m muster) SyslogNetHandler(net, addr string, priority syslog.Priority, tag string, fmtr Format) Handler {
+	return must(SyslogNetHandler(net, addr, priority, tag, fmtr))
+}