M agent.go → agent.go

@@ -11,7 +11,7 @@ 
 // Agent starts and manages a Serf & adds
 // service discovery
 type Agent struct {
-	conf     *Config
+//	conf     *Config
 	serfConf *serf.Config
 	eventCh  chan serf.Event
 
@@ -29,14 +29,13 @@ shutdownCh   chan struct{}
 	shutdownLock sync.Mutex
 }
 
-func Create(conf *Config, serfConf *serf.Config) *Agent {
+func Create(serfConf *serf.Config) *Agent {
 	// Create a channel to listen for events from Serf
 	eventCh := make(chan serf.Event, 64)
 	serfConf.EventCh = eventCh
 
 	// Setup the agent
 	agent := &Agent{
-		conf:       conf,
 		serfConf:   serfConf,
 		eventCh:    eventCh,
 		shutdownCh: make(chan struct{}),
@@ -51,10 +50,10 @@ serfShutdownCh := a.serf.ShutdownCh()
 	for {
 		select {
 		case e := <-a.eventCh:
-			log.Printf("[INFO] agent: Received event: %s", e.String())
+			log.Printf("[INFO] cascade: Received event: %s", e.String())
 
 		case <-serfShutdownCh:
-			log.Printf("[WARN] agent: Serf shutdown detected, quitting")
+			log.Printf("[WARN] cascade: Serf shutdown detected, quitting")
 			a.Shutdown()
 			return
 
@@ -65,7 +64,7 @@ }
 }
 
 func (a *Agent) Start() error {
-	log.Printf("[INFO] agent: Serf agent starting")
+	log.Printf("[INFO] cascade: Serf agent starting")
 
 	// Create serf first
 	serf, err := serf.Create(a.serfConf)
@@ -93,30 +92,31 @@ if a.serf == nil {
 		goto EXIT
 	}
 
-	log.Println("[INFO] agent: requesting serf shutdown")
+	log.Println("[INFO] cascade: requesting serf shutdown")
 	if err := a.serf.Shutdown(); err != nil {
 		return err
 	}
 
 EXIT:
-	log.Println("[INFO] agent: shutdown complete")
+	log.Println("[INFO] cascade: shutdown complete")
 	a.shutdown = true
 	close(a.shutdownCh)
 	return nil
 }
 
 // Join asks the Serf instance to join. See the Serf.Join function.
-func (a *Agent) Join(addrs []string, replay bool) (n int, err error) {
-	log.Printf("[INFO] agent: joining: %v replay: %v", addrs, replay)
-	ignoreOld := !replay
-	n, err = a.serf.Join(addrs, ignoreOld)
+func (a *Agent) Join(addrs []string) (n int, err error) {
+	log.Printf("[INFO] cascade: joining: %v", addrs)
+	// we always ignore old events because cascade don't
+	// care about the past
+	n, err = a.serf.Join(addrs, true)
 	if n > 0 {
-		log.Printf("[INFO] agent: joined: %d nodes", n)
+		log.Printf("[INFO] cascade: joined: %d nodes", n)
 	}
 	if err != nil {
-		log.Printf("[WARN] agent: error joining: %v", err)
+		log.Printf("[WARN] cascade: error joining: %v", err)
 	}
-	return
+	return n, err
 }
 
 // Leave prepares for a graceful shutdown of the agent and its processes
@@ -125,6 +125,6 @@ if a.serf == nil {
 		return nil
 	}
 
-	log.Println("[INFO] agent: requesting graceful leave from Serf")
+	log.Println("[INFO] cascade: requesting graceful leave from Serf")
 	return a.serf.Leave()
 }

M config.go → config.go

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

M main.go → main.go

@@ -11,6 +11,7 @@ 
 import (
 	"log"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/hashicorp/memberlist"
@@ -18,14 +19,44 @@ "github.com/hashicorp/serf/serf"
 )
 
 func main() {
-	c := DefaultConfig()
+	config := readConfig()
+	agent := setupAgent(config)
+	if err := agent.Start(); err != nil {
+		log.Panic(err)
+	}
+	defer agent.Shutdown()
+	// join any specified startup nodes
+	if err := startupJoin(config, agent); err != nil {
+		log.Panic(err)
+	}
+//	handleSignals(config, agent)
+}
+
+func readConfig() *Config {
+	config := DefaultConfig()
 	if os.Getenv("CASCADE_BIND") != "" {
-		c.BindAddr = os.Getenv("CASCADE_BIND")
+		config.BindAddr = os.Getenv("CASCADE_BIND")
+	}
+	// CASCADE_JOIN=127.0.0.1,127.0.0.5
+	if os.Getenv("CASCADE_JOIN") != "" {
+		config.StartJoin = strings.Split(os.Getenv("CASCADE_JOIN"), ",")
+	}
+	return config
+}
+
+func startupJoin(config *Config, agent *Agent) error {
+	if len(config.StartJoin) == 0 {
+		return nil
 	}
-	// agent does everything tbh
-	agent := setupAgent(c)
-	log.Println(agent)
-	// agent.Run()
+
+	log.Printf("Joining cluster...")
+	n, err := agent.Join(config.StartJoin)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Join completed. Synced with %d initial agents", n)
+	return nil
 }
 
 func setupAgent(config *Config) *Agent {
@@ -60,6 +91,6 @@ serfConfig.MemberlistConfig = memberlist.DefaultWANConfig()
 	serfConfig.MemberlistConfig.BindAddr = bindIP
 	serfConfig.MemberlistConfig.BindPort = bindPort
 
-	agent := Create(config, serfConfig)
+	agent := Create(serfConfig)
 	return agent
 }