M .gitignore → .gitignore

@@ -1,1 +1,1 @@ 
-,*
+cascade

M agent.go → agent.go

@@ -128,3 +128,9 @@ 
 	log.Println("[INFO] cascade: requesting graceful leave from Serf")
 	return a.serf.Leave()
 }
+
+// ShutdownCh returns a channel that can be selected to wait
+// for the agent to perform a shutdown.
+func (a *Agent) ShutdownCh() <-chan struct{} {
+	return a.shutdownCh
+}

M config.go → config.go

@@ -23,6 +23,7 @@ }
 
 type Config struct {
 	BindAddr string
+	NodeName string
 	StartJoin []string
 	Services []Service
 }

M main.go → main.go

@@ -9,15 +9,23 @@ 
 package main
 
 import (
+	"fmt"
 	"log"
 	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/hashicorp/memberlist"
 	"github.com/hashicorp/serf/serf"
 )
 
+const (
+	// gracefulTimeout controls how long we wait before forcefully terminating
+	gracefulTimeout = 3 * time.Second
+)
+
 func main() {
 	config := readConfig()
 	agent := setupAgent(config)
@@ -29,11 +37,64 @@ // join any specified startup nodes
 	if err := startupJoin(config, agent); err != nil {
 		log.Panic(err)
 	}
-//	handleSignals(config, agent)
+	if err := handleSignals(config, agent); err != nil {
+		log.Panic(err)
+	}
+}
+
+// handleSignals blocks until we get an exit-causing signal
+func handleSignals(config *Config, agent *Agent) error {
+	signalCh := make(chan os.Signal, 4)
+	signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM)
+
+	// Wait for a signal
+	var sig os.Signal
+	select {
+	case s := <-signalCh:
+		sig = s
+	case <-agent.ShutdownCh():
+		// Agent is already shutdown!
+		return nil
+	}
+	log.Printf("Caught signal: %v", sig)
+
+	// Check if we should do a graceful leave
+	graceful := false
+	if sig == os.Interrupt || sig == syscall.SIGTERM {
+		graceful = true
+	}
+
+	// Bail fast if not doing a graceful leave
+	if !graceful {
+		log.Printf("[WARN] cascade: non-graceful leave detected")
+		return nil
+	}
+
+	// Attempt a graceful leave
+	gracefulCh := make(chan struct{})
+	log.Println("Gracefully shutting down agent...")
+	go func() {
+		if err := agent.Leave(); err != nil {
+			log.Printf("Error: %s", err)
+			return
+		}
+		close(gracefulCh)
+	}()
+
+	// Wait for leave or another signal
+	select {
+	case <-signalCh:
+		return fmt.Errorf("[WARN] cascade: idk")
+	case <-time.After(gracefulTimeout):
+		return fmt.Errorf("[WARN] cascade: leave timed out")
+	case <-gracefulCh:
+		return nil
+	}
 }
 
 func readConfig() *Config {
 	config := DefaultConfig()
+	// CASCADE_BIND=127.0.0.1:1234
 	if os.Getenv("CASCADE_BIND") != "" {
 		config.BindAddr = os.Getenv("CASCADE_BIND")
 	}
@@ -41,6 +102,10 @@ // CASCADE_JOIN=127.0.0.1,127.0.0.5
 	if os.Getenv("CASCADE_JOIN") != "" {
 		config.StartJoin = strings.Split(os.Getenv("CASCADE_JOIN"), ",")
 	}
+	// CASCADE_NAME=nostromo.j3s.sh
+	if os.Getenv("CASCADE_NAME") != "" {
+		config.NodeName = os.Getenv("CASCADE_NAME")
+	}
 	return config
 }
 
@@ -65,10 +130,7 @@ if err != nil {
 		log.Panic(err)
 	}
 	serfConfig := serf.DefaultConfig()
-	serfConfig.MemberlistConfig.BindAddr = bindIP
-	serfConfig.MemberlistConfig.BindPort = bindPort
-	serfConfig.MemberlistConfig.AdvertiseAddr = ""
-	serfConfig.MemberlistConfig.AdvertisePort = 0
+	serfConfig.NodeName = config.NodeName
 	serfConfig.ProtocolVersion = uint8(serf.ProtocolVersionMax)
 	serfConfig.CoalescePeriod = 3 * time.Second
 	serfConfig.QuiescentPeriod = time.Second
@@ -84,12 +146,13 @@ serfConfig.TombstoneTimeout = 0
 	serfConfig.BroadcastTimeout = 0
 	// TODO: what are the implications of true here o_O
 	serfConfig.EnableNameConflictResolution = true
-
 	// hardcode DefaultWANConfig because cascade is designed to be
 	// used as a single global system.
 	serfConfig.MemberlistConfig = memberlist.DefaultWANConfig()
 	serfConfig.MemberlistConfig.BindAddr = bindIP
 	serfConfig.MemberlistConfig.BindPort = bindPort
+	serfConfig.MemberlistConfig.AdvertiseAddr = ""
+	serfConfig.MemberlistConfig.AdvertisePort = 0
 
 	agent := Create(serfConfig)
 	return agent