Use interface name instead of cluster name

The cluster name option is not required anymore and
removed, the interface name is used to name the cluster
directly. For backward compatibility, the old path for storing
cluster state is tried as a fallback when loading.

cluster/state.go

@@ -17,10 +17,12 @@ type state struct {
 	Nodes      []common.Node
 }
 
-var defaultStatePath = "/var/lib/wesher/%s.json"
+var statePathTemplate = "/var/lib/wesher/%s.json"
+
+const deprecatedStatePath = "/var/lib/wesher/state.json"
 
 func (s *state) save(clusterName string) error {
-	statePath := fmt.Sprintf(defaultStatePath, clusterName)
+	statePath := fmt.Sprintf(statePathTemplate, clusterName)
 	if err := os.MkdirAll(path.Dir(statePath), 0700); err != nil {
 		return err
 	}
@@ -34,13 +36,21 @@ func (s *state) save(clusterName string) error {
 }
 
 func loadState(cs *state, clusterName string) {
-	statePath := fmt.Sprintf(defaultStatePath, clusterName)
+	statePath := fmt.Sprintf(statePathTemplate, clusterName)
 	content, err := ioutil.ReadFile(statePath)
 	if err != nil {
-		if !os.IsNotExist(err) {
-			logrus.Warnf("could not open state in %s: %s", statePath, err)
+		// try the deprecated pre 0.3 state path, it will later
+		// be saved to the proper path
+		if os.IsNotExist(err) {
+			content, err = ioutil.ReadFile(deprecatedStatePath)
+		}
+
+		if err != nil {
+			if !os.IsNotExist(err) {
+				logrus.Warnf("could not open state in %s: %s", statePath, err)
+			}
+			return
 		}
-		return
 	}
 
 	// avoid partially unmarshalled content by using a temp var

cluster/state_test.go

@@ -9,7 +9,7 @@ import (
 )
 
 func Test_state_save_soad(t *testing.T) {
-	defaultStatePath = "/tmp/%s.json"
+	statePathTemplate = "/tmp/%s.json"
 	key := "abcdefghijklmnopqrstuvwxyzABCDEF"
 	node := common.Node{
 		Name: "node",