use list of IPs as a discovery

Signed-off-by: Victor Vieux <vieux@docker.com>

discovery/list/list.go

@@ -0,0 +1,33 @@
+package list
+
+import (
+	"strings"
+
+	"github.com/docker/swarm/discovery"
+)
+
+type ListDiscoveryService struct {
+	list []*discovery.Node
+}
+
+func init() {
+	discovery.Register("list", &ListDiscoveryService{})
+}
+
+func (s *ListDiscoveryService) Initialize(uris string, _ int) error {
+	for _, ip := range strings.Split(uris, ",") {
+		s.list = append(s.list, discovery.NewNode(ip))
+	}
+
+	return nil
+}
+func (s *ListDiscoveryService) Fetch() ([]*discovery.Node, error) {
+	return s.list, nil
+}
+
+func (s *ListDiscoveryService) Watch(callback discovery.WatchCallback) {
+}
+
+func (s *ListDiscoveryService) Register(addr string) error {
+	return discovery.ErrNotImplemented
+}

discovery/list/list_test.go

@@ -0,0 +1,20 @@
+package list
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestInitialise(t *testing.T) {
+	discovery := &ListDiscoveryService{}
+	discovery.Initialize("1.1.1.1:1111,2.2.2.2:2222", 0)
+	assert.Equal(t, len(discovery.list), 2)
+	assert.Equal(t, discovery.list[0].String(), "http://1.1.1.1:1111")
+	assert.Equal(t, discovery.list[1].String(), "http://2.2.2.2:2222")
+}
+
+func TestRegister(t *testing.T) {
+	discovery := &ListDiscoveryService{}
+	assert.Error(t, discovery.Register("0.0.0.0"))
+}

main.go

@@ -11,6 +11,7 @@ import (
 	_ "github.com/docker/swarm/discovery/consul"
 	_ "github.com/docker/swarm/discovery/etcd"
 	_ "github.com/docker/swarm/discovery/file"
+	_ "github.com/docker/swarm/discovery/list"
 	"github.com/docker/swarm/discovery/token"
 	_ "github.com/docker/swarm/discovery/zookeeper"
 )

manage.go

@@ -74,29 +74,9 @@ func manage(c *cli.Context) {
 	cluster := cluster.NewCluster(tlsConfig)
 	cluster.Events(&logHandler{})
 
-	go func() {
-		if c.String("discovery") != "" {
-			d, err := discovery.New(c.String("discovery"), c.Int("heartbeat"))
-			if err != nil {
-				log.Fatal(err)
-			}
-
-			nodes, err := d.Fetch()
-			if err != nil {
-				log.Fatal(err)
-
-			}
-			cluster.UpdateNodes(nodes)
-
-			go d.Watch(cluster.UpdateNodes)
-		} else {
-			var nodes []*discovery.Node
-			for _, arg := range c.Args() {
-				nodes = append(nodes, discovery.NewNode(arg))
-			}
-			cluster.UpdateNodes(nodes)
-		}
-	}()
+	if !c.IsSet("discovery") {
+		log.Fatal("--discovery required to manage a cluster")
+	}
 
 	s, err := strategy.New(c.String("strategy"))
 	if err != nil {
@@ -112,6 +92,24 @@ func manage(c *cli.Context) {
 	if err != nil {
 		log.Fatal(err)
 	}
+
+	// get the list of nodes from the discovery service
+	go func() {
+		d, err := discovery.New(c.String("discovery"), c.Int("heartbeat"))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		nodes, err := d.Fetch()
+		if err != nil {
+			log.Fatal(err)
+
+		}
+		cluster.UpdateNodes(nodes)
+
+		go d.Watch(cluster.UpdateNodes)
+	}()
+
 	sched := scheduler.NewScheduler(
 		cluster,
 		s,