discarded host handler

discarded-host.go

@@ -0,0 +1,79 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"sync"
+	"time"
+)
+
+type DiscardedHost struct {
+	*Connection
+	Host  string
+	Tries int
+}
+
+type DiscardedHostHandler struct {
+	mu           sync.RWMutex
+	port         int
+	hosts        []*DiscardedHost
+	onConnection *func(string)
+}
+
+func (d *DiscardedHostHandler) run() {
+	for range time.Tick(time.Second) {
+		d.mu.RLock()
+		lst := make([]*DiscardedHost, 0, len(d.hosts))
+		for _, host := range d.hosts {
+			if host.Tries >= 0 || host.Tries < 5 {
+				go d.testConnection(host)
+				lst = append(lst, host)
+			}
+		}
+		d.mu.RUnlock()
+		d.mu.Lock()
+		d.hosts = lst
+		d.mu.Unlock()
+	}
+
+}
+
+func (d *DiscardedHostHandler) testConnection(host *DiscardedHost) {
+	addr := fmt.Sprintf("%s:%d", host.Host, d.port)
+	conn, err := net.Dial("tcp", addr)
+
+	if err != nil {
+		host.Tries++
+		host.Tries = -1
+	} else {
+		conn.Close()
+		if d.onConnection != nil {
+			fn := *d.onConnection
+			fn(host.Host)
+		}
+	}
+}
+
+func NewDiscardedHostHandler(port int) *DiscardedHostHandler {
+	ret := &DiscardedHostHandler{
+		hosts: make([]*DiscardedHost, 0),
+		port:  port,
+	}
+	go ret.run()
+	return ret
+}
+
+func (d *DiscardedHostHandler) SetReconnectHandler(fn func(string)) {
+	d.onConnection = &fn
+}
+
+func (d *DiscardedHostHandler) AppendHost(host string) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	log.Printf("Retrying host %s", host)
+	d.hosts = append(d.hosts, &DiscardedHost{
+		Host:  host,
+		Tries: 0,
+	})
+}

discarded-host_test.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"testing"
+	"time"
+)
+
+func TestDiscardedHost(t *testing.T) {
+	dh := NewDiscardedHostHandler(func(host string) {
+		t.Log(host)
+	}, 8080)
+	dh.AppendHost("localhost")
+	time.Sleep(2 * time.Second)
+	if dh.hosts[0].Tries == 0 {
+		t.Error("Host not tested")
+	}
+}

synced-pool.go

@@ -24,6 +24,7 @@ type HealthHandler interface {
 type SyncedPool struct {
 	Server               *GenericListener
 	mu                   sync.RWMutex
+	discardedHostHandler *DiscardedHostHandler
 	Hostname             string
 	local                *GrainLocalPool
 	remotes              map[string]*RemoteHost
@@ -110,13 +111,13 @@ func (p *SyncedPool) GrainOwnerChangeHandler(data *FrameWithPayload, resultChan
 
 	idAndHostParts := strings.Split(string(data.Payload), ";")
 	if len(idAndHostParts) != 2 {
-		log.Printf("Invalid remote grain change message\n")
+		log.Printf("Invalid remote grain change message")
 		resultChan <- MakeFrameWithPayload(AckError, 500, []byte("invalid"))
 		return nil
 	}
 	id := ToCartId(idAndHostParts[0])
 	host := idAndHostParts[1]
-	log.Printf("Handling remote grain owner change to %s for id %s\n", host, id)
+	log.Printf("Handling remote grain owner change to %s for id %s", host, id)
 	for _, r := range p.remotes {
 		if r.Host == host && r.IsHealthy() {
 			go p.SpawnRemoteGrain(id, host)
@@ -136,11 +137,11 @@ func (p *SyncedPool) RemoveRemoteGrain(id CartId) {
 
 func (p *SyncedPool) SpawnRemoteGrain(id CartId, host string) {
 	if id.String() == "" {
-		log.Printf("Invalid grain id, %s\n", id)
+		log.Printf("Invalid grain id, %s", id)
 		return
 	}
 	if p.local.grains[id] != nil {
-		log.Printf("Grain %s already exists locally, owner is (%s)\n", id, host)
+		log.Printf("Grain %s already exists locally, owner is (%s)", id, host)
 		p.mu.Lock()
 		delete(p.local.grains, id)
 		p.mu.Unlock()
@@ -148,15 +149,9 @@ func (p *SyncedPool) SpawnRemoteGrain(id CartId, host string) {
 
 	remote, err := NewRemoteGrain(id, host)
 	if err != nil {
-		log.Printf("Error creating remote grain %v\n", err)
+		log.Printf("Error creating remote grain %v", err)
 		return
 	}
-	// go func() {
-	// 	<-remote.Died
-	// 	p.RemoveRemoteGrain(id)
-	// 	p.HandleHostError(host)
-	// 	log.Printf("Remote grain %s died, host: %s\n", id.String(), host)
-	// }()
 
 	p.mu.Lock()
 	p.remoteIndex[id] = remote
@@ -183,16 +178,16 @@ func NewSyncedPool(local *GrainLocalPool, hostname string, discovery Discovery)
 	}
 
 	log.Printf("Listening on %s", listen)
-
+	dh := NewDiscardedHostHandler(1338)
 	pool := &SyncedPool{
 		Server:               server,
 		Hostname:             hostname,
 		local:                local,
-
+		discardedHostHandler: dh,
 		remotes:              make(map[string]*RemoteHost),
 		remoteIndex:          make(map[CartId]*RemoteGrain),
 	}
-
+	dh.SetReconnectHandler(pool.AddRemote)
 	server.AddHandler(Ping, pool.PongHandler)
 	server.AddHandler(GetCartIds, pool.GetCartIdHandler)
 	server.AddHandler(RemoteNegotiate, pool.NegotiateHandler)
@@ -266,11 +261,11 @@ func (p *SyncedPool) ExcludeKnown(hosts []string) []string {
 }
 
 func (p *SyncedPool) RemoveHost(host *RemoteHost) {
-
 	p.mu.Lock()
 	delete(p.remotes, host.Host)
 	p.mu.Unlock()
 	p.RemoveHostMappedCarts(host)
+	p.discardedHostHandler.AppendHost(host.Host)
 	connectedRemotes.Set(float64(len(p.remotes)))
 }