Log all output of logrus to syslog as well as stdout/stderr

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #1084
Approved by: baude

cmd/podman/main.go

@@ -14,7 +14,9 @@ import (
 	"github.com/projectatomic/libpod/pkg/rootless"
 	"github.com/projectatomic/libpod/version"
 	"github.com/sirupsen/logrus"
+	lsyslog "github.com/sirupsen/logrus/hooks/syslog"
 	"github.com/urfave/cli"
+	"log/syslog"
 )
 
 // This is populated by the Makefile from the VERSION file
@@ -94,6 +96,12 @@ func main() {
 	}
 
 	app.Before = func(c *cli.Context) error {
+		if c.GlobalBool("syslog") {
+			hook, err := lsyslog.NewSyslogHook("", "", syslog.LOG_INFO, "")
+			if err == nil {
+				logrus.AddHook(hook)
+			}
+		}
 		logLevel := c.GlobalString("log-level")
 		if logLevel != "" {
 			level, err := logrus.ParseLevel(logLevel)
@@ -187,6 +195,10 @@ func main() {
 			Name:  "storage-opt",
 			Usage: "used to pass an option to the storage driver",
 		},
+		cli.BoolFlag{
+			Name:  "syslog",
+			Usage: "output logging information to syslog as well as the console",
+		},
 	}
 	if _, err := os.Stat("/etc/containers/registries.conf"); err != nil {
 		if os.IsNotExist(err) {

completions/bash/podman

@@ -2026,6 +2026,7 @@ _podman_podman() {
      local boolean_options="
            --help -h
            --version -v
+           --syslog
      "
      commands="
     attach

docs/podman.1.md

@@ -59,6 +59,10 @@ Select which storage driver is used to manage storage of images and containers (
 
 Used to pass an option to the storage driver
 
+**--syslog**
+
+output logging information to syslog as well as the console
+
 **--version, -v**
 
 Print the version

vendor/github.com/sirupsen/logrus/hooks/syslog/README.md

@@ -0,0 +1,39 @@
+# Syslog Hooks for Logrus <img src="http://i.imgur.com/hTeVwmJ.png" width="40" height="40" alt=":walrus:" class="emoji" title=":walrus:"/>
+
+## Usage
+
+```go
+import (
+  "log/syslog"
+  "github.com/sirupsen/logrus"
+  logrus_syslog "github.com/sirupsen/logrus/hooks/syslog"
+)
+
+func main() {
+  log       := logrus.New()
+  hook, err := logrus_syslog.NewSyslogHook("udp", "localhost:514", syslog.LOG_INFO, "")
+
+  if err == nil {
+    log.Hooks.Add(hook)
+  }
+}
+```
+
+If you want to connect to local syslog (Ex. "/dev/log" or "/var/run/syslog" or "/var/run/log"). Just assign empty string to the first two parameters of `NewSyslogHook`. It should look like the following.
+
+```go
+import (
+  "log/syslog"
+  "github.com/sirupsen/logrus"
+  logrus_syslog "github.com/sirupsen/logrus/hooks/syslog"
+)
+
+func main() {
+  log       := logrus.New()
+  hook, err := logrus_syslog.NewSyslogHook("", "", syslog.LOG_INFO, "")
+
+  if err == nil {
+    log.Hooks.Add(hook)
+  }
+}
+```

vendor/github.com/sirupsen/logrus/hooks/syslog/syslog.go

@@ -0,0 +1,54 @@
+// +build !windows,!nacl,!plan9
+
+package logrus_syslog
+
+import (
+	"fmt"
+	"github.com/sirupsen/logrus"
+	"log/syslog"
+	"os"
+)
+
+// SyslogHook to send logs via syslog.
+type SyslogHook struct {
+	Writer        *syslog.Writer
+	SyslogNetwork string
+	SyslogRaddr   string
+}
+
+// Creates a hook to be added to an instance of logger. This is called with
+// `hook, err := NewSyslogHook("udp", "localhost:514", syslog.LOG_DEBUG, "")`
+// `if err == nil { log.Hooks.Add(hook) }`
+func NewSyslogHook(network, raddr string, priority syslog.Priority, tag string) (*SyslogHook, error) {
+	w, err := syslog.Dial(network, raddr, priority, tag)
+	return &SyslogHook{w, network, raddr}, err
+}
+
+func (hook *SyslogHook) Fire(entry *logrus.Entry) error {
+	line, err := entry.String()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Unable to read entry, %v", err)
+		return 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)
+	case logrus.WarnLevel:
+		return hook.Writer.Warning(line)
+	case logrus.InfoLevel:
+		return hook.Writer.Info(line)
+	case logrus.DebugLevel:
+		return hook.Writer.Debug(line)
+	default:
+		return nil
+	}
+}
+
+func (hook *SyslogHook) Levels() []logrus.Level {
+	return logrus.AllLevels
+}