server: Move all the top level files into cmd folder. (#2490)

This change brings a change which was done for the 'mc'
package to allow for clean repo and have a cleaner
github drop in experience.

cmd/logger-syslog-hook_nix.go

@@ -0,0 +1,82 @@
+// +build !windows
+
+/*
+ * Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
+ *
+ * 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.
+ */
+
+package cmd
+
+import (
+	"fmt"
+	"log/syslog"
+
+	"github.com/Sirupsen/logrus"
+)
+
+type syslogLogger struct {
+	Enable bool   `json:"enable"`
+	Addr   string `json:"address"`
+	Level  string `json:"level"`
+}
+
+// syslogHook to send logs via syslog.
+type syslogHook struct {
+	writer        *syslog.Writer
+	syslogNetwork string
+	syslogRaddr   string
+}
+
+// enableSyslogLogger - enable logger at raddr.
+func enableSyslogLogger(raddr string) {
+	syslogHook, err := newSyslog("udp", raddr, syslog.LOG_ERR, "MINIO")
+	fatalIf(err, "Unable to initialize syslog logger.")
+
+	log.Hooks.Add(syslogHook)               // Add syslog hook.
+	log.Formatter = &logrus.JSONFormatter{} // JSON formatted log.
+	log.Level = logrus.ErrorLevel           // Minimum log level.
+}
+
+// newSyslog - Creates a hook to be added to an instance of logger.
+func newSyslog(network, raddr string, priority syslog.Priority, tag string) (*syslogHook, error) {
+	w, err := syslog.Dial(network, raddr, priority, tag)
+	return &syslogHook{w, network, raddr}, err
+}
+
+// Fire - fire the log event
+func (hook *syslogHook) Fire(entry *logrus.Entry) error {
+	line, err := entry.String()
+	if err != nil {
+		return fmt.Errorf("Unable to read entry, %v", err)
+	}
+	switch entry.Level {
+	case logrus.PanicLevel:
+		return hook.writer.Crit(line)
+	case logrus.FatalLevel:
+		return hook.writer.Crit(line)
+	case logrus.ErrorLevel:
+		return hook.writer.Err(line)
+	default:
+		return nil
+	}
+}
+
+// Levels -
+func (hook *syslogHook) Levels() []logrus.Level {
+	return []logrus.Level{
+		logrus.PanicLevel,
+		logrus.FatalLevel,
+		logrus.ErrorLevel,
+	}
+}