From 85207e0a7729554ea7ef4a5a8affdc716c862dfc Mon Sep 17 00:00:00 2001
From: Julien Riou <julien.riou@outlook.com>
Date: Sun, 24 Jun 2018 16:10:26 +0200
Subject: [PATCH] Add syslog notifier

---
 base/config.go          |  2 ++
 cmd/pgterminate/main.go | 11 ++++++
 config.yaml.example     |  2 ++
 notifier/notifier.go    |  3 ++
 notifier/syslog.go      | 79 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 97 insertions(+)
 create mode 100644 notifier/syslog.go

diff --git a/base/config.go b/base/config.go
index 82fd21c..cfb528e 100644
--- a/base/config.go
+++ b/base/config.go
@@ -28,6 +28,8 @@ type Config struct {
 	ActiveTimeout  float64 `yaml:"active-timeout"`
 	LogFile        string  `yaml:"log-file"`
 	PidFile        string  `yaml:"pid-file"`
+	SyslogIdent    string  `yaml:"syslog-ident"`
+	SyslogFacility string  `yaml:"syslog-facility"`
 }
 
 func init() {
diff --git a/cmd/pgterminate/main.go b/cmd/pgterminate/main.go
index 6ebeaef..e47c1cf 100644
--- a/cmd/pgterminate/main.go
+++ b/cmd/pgterminate/main.go
@@ -10,6 +10,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"regexp"
 	"strconv"
 	"sync"
 	"syscall"
@@ -36,6 +37,8 @@ func main() {
 	flag.Float64Var(&config.ActiveTimeout, "active-timeout", 0, "Time for active connections to be terminated in seconds")
 	flag.StringVar(&config.LogFile, "log-file", "", "Write logs to a file")
 	flag.StringVar(&config.PidFile, "pid-file", "", "Write process id into a file")
+	flag.StringVar(&config.SyslogIdent, "syslog-ident", "pgterminate", "Define syslog tag")
+	flag.StringVar(&config.SyslogFacility, "syslog-facility", "", "Define syslog facility from LOCAL0 to LOCAL7")
 	flag.Parse()
 
 	if *version {
@@ -63,6 +66,14 @@ func main() {
 		log.Fatalln("Parameter -active-timeout or -idle-timeout required")
 	}
 
+	if config.SyslogFacility != "" {
+		matched, err := regexp.MatchString("^LOCAL[0-7]$", config.SyslogFacility)
+		base.Panic(err)
+		if !matched {
+			log.Fatalln("Syslog facility must range from LOCAL0 to LOCAL7")
+		}
+	}
+
 	if config.PidFile != "" {
 		writePid(config.PidFile)
 		defer removePid(config.PidFile)
diff --git a/config.yaml.example b/config.yaml.example
index 86108b4..f10adb7 100644
--- a/config.yaml.example
+++ b/config.yaml.example
@@ -9,3 +9,5 @@ idle-timeout: 300
 active-timeout: 10
 log-file: /var/log/pgterminate/pgterminate.log
 pid-file: /var/run/pgterminate/pgterminate.pid
+#syslog-ident: pgterminate
+#syslog-facility: LOCAL0
diff --git a/notifier/notifier.go b/notifier/notifier.go
index 9a8ea21..2c6921e 100644
--- a/notifier/notifier.go
+++ b/notifier/notifier.go
@@ -16,5 +16,8 @@ func NewNotifier(ctx *base.Context) Notifier {
 	if ctx.Config.LogFile != "" {
 		return NewFile(ctx.Config.LogFile, ctx.Sessions)
 	}
+	if ctx.Config.SyslogFacility != "" {
+		return NewSyslog(ctx.Config.SyslogFacility, ctx.Config.SyslogIdent, ctx.Sessions)
+	}
 	return NewConsole(ctx.Sessions)
 }
diff --git a/notifier/syslog.go b/notifier/syslog.go
new file mode 100644
index 0000000..8ca7ec0
--- /dev/null
+++ b/notifier/syslog.go
@@ -0,0 +1,79 @@
+package notifier
+
+import (
+	"fmt"
+	"github.com/jouir/pgterminate/base"
+	"log/syslog"
+)
+
+// Syslog notifier
+type Syslog struct {
+	sessions chan base.Session
+	ident    string
+	priority syslog.Priority
+	writer   *syslog.Writer
+}
+
+// NewSyslog creates a syslog notifier
+func NewSyslog(facility string, ident string, sessions chan base.Session) Notifier {
+	var priority syslog.Priority
+	switch facility {
+	case "LOCAL0":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL0
+	case "LOCAL1":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL1
+	case "LOCAL2":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL2
+	case "LOCAL3":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL3
+	case "LOCAL4":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL4
+	case "LOCAL5":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL5
+	case "LOCAL6":
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL6
+	default: // LOCAL7
+		priority = syslog.LOG_INFO | syslog.LOG_LOCAL7
+	}
+	return &Syslog{
+		sessions: sessions,
+		ident:    ident,
+		priority: priority,
+	}
+}
+
+// Run starts syslog notifier
+func (s *Syslog) Run() {
+	var err error
+	if s.writer, err = syslog.New(s.priority, s.ident); err != nil {
+		base.Panic(err)
+	}
+	for session := range s.sessions {
+		s.writer.Info(fmt.Sprintf("%s", session))
+	}
+}
+
+// Reload disconnect from syslog daemon and re-connect
+// Executed when receiving SIGHUP signal
+func (s *Syslog) Reload() {
+	if s.writer != nil {
+		s.disconnect()
+		s.connect()
+	}
+}
+
+// connect to syslog daemon
+func (s *Syslog) connect() {
+	var err error
+	if s.writer, err = syslog.New(s.priority, s.ident); err != nil {
+		base.Panic(err)
+	}
+}
+
+// disconnect from syslog daemon
+func (s *Syslog) disconnect() {
+	var err error
+	if err = s.writer.Close(); err != nil {
+		base.Panic(err)
+	}
+}