Standardize exit codes and improve shutdown handling; update gitignore

sigtrap.go

@@ -0,0 +1,82 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// 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 caddy
+
+import (
+	"log"
+	"os"
+	"os/signal"
+
+	"github.com/mholt/certmagic"
+)
+
+// TrapSignals create signal/interrupt handlers as best it can for the
+// current OS. This is a rather invasive function to call in a Go program
+// that captures signals already, so in that case it would be better to
+// implement these handlers yourself.
+func TrapSignals() {
+	trapSignalsCrossPlatform()
+	trapSignalsPosix()
+}
+
+// trapSignalsCrossPlatform captures SIGINT or interrupt (depending
+// on the OS), which initiates a graceful shutdown. A second SIGINT
+// or interrupt will forcefully exit the process immediately.
+func trapSignalsCrossPlatform() {
+	go func() {
+		shutdown := make(chan os.Signal, 1)
+		signal.Notify(shutdown, os.Interrupt)
+
+		for i := 0; true; i++ {
+			<-shutdown
+
+			if i > 0 {
+				log.Println("[INFO] SIGINT: Force quit")
+				os.Exit(ExitCodeForceQuit)
+			}
+
+			log.Println("[INFO] SIGINT: Shutting down")
+			go gracefulStop("SIGINT")
+		}
+	}()
+}
+
+// gracefulStop exits the process as gracefully as possible.
+func gracefulStop(sigName string) {
+	exitCode := ExitCodeSuccess
+
+	// first stop all the apps
+	err := Stop()
+	if err != nil {
+		log.Printf("[ERROR] %s stop: %v", sigName, err)
+		exitCode = ExitCodeFailedQuit
+	}
+
+	// always, always, always try to clean up locks
+	certmagic.CleanUpOwnLocks()
+
+	log.Printf("[INFO] %s: Shutdown done", sigName)
+	os.Exit(exitCode)
+}
+
+// Exit codes. Generally, you will want to avoid
+// automatically restarting the process if the
+// exit code is 1.
+const (
+	ExitCodeSuccess = iota
+	ExitCodeFailedStartup
+	ExitCodeForceQuit
+	ExitCodeFailedQuit
+)