From 4b03d7fa0c604209424c5a9205f2a2f03ead68b2 Mon Sep 17 00:00:00 2001
From: Victor Vieux <victorvieux@gmail.com>
Date: Mon, 18 May 2015 12:56:21 -0700
Subject: [PATCH] handle collision

Signed-off-by: Victor Vieux <victorvieux@gmail.com>
---
 cluster/swarm/cluster.go      | 16 ++++++++++++++--
 cluster/swarm/cluster_test.go | 20 +++++++++++---------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/cluster/swarm/cluster.go b/cluster/swarm/cluster.go
index b08f988288..440066ce7b 100644
--- a/cluster/swarm/cluster.go
+++ b/cluster/swarm/cluster.go
@@ -388,6 +388,8 @@ func (c *Cluster) Container(IDOrName string) *cluster.Container {
 		}
 	}
 
+	candidates := []*cluster.Container{}
+
 	// Match name, /name or engine/name.
 	for _, container := range containers {
 		for _, name := range container.Names {
@@ -397,20 +399,30 @@ func (c *Cluster) Container(IDOrName string) *cluster.Container {
 		}
 	}
 
+	if size := len(candidates); size == 1 {
+		return candidates[0]
+	} else if size > 1 {
+		return nil
+	}
+
 	// Match Container ID prefix.
 	for _, container := range containers {
 		if strings.HasPrefix(container.Id, IDOrName) {
-			return container
+			candidates = append(candidates, container)
 		}
 	}
 
 	// Match Swarm ID prefix.
 	for _, container := range containers {
 		if strings.HasPrefix(container.Config.SwarmID(), IDOrName) {
-			return container
+			candidates = append(candidates, container)
 		}
 	}
 
+	if len(candidates) == 1 {
+		return candidates[0]
+	}
+
 	return nil
 }
 
diff --git a/cluster/swarm/cluster_test.go b/cluster/swarm/cluster_test.go
index 3cfb6dab5f..b870908836 100644
--- a/cluster/swarm/cluster_test.go
+++ b/cluster/swarm/cluster_test.go
@@ -27,24 +27,24 @@ func TestContainerLookup(t *testing.T) {
 	}
 	container1 := &cluster.Container{
 		Container: dockerclient.Container{
-			Id:    "container-id1",
+			Id:    "container1-id",
 			Names: []string{"/container1-name1", "/container1-name2"},
 		},
 		Config: cluster.BuildContainerConfig(dockerclient.ContainerConfig{
 			Labels: map[string]string{
-				"com.docker.swarm.id": "swarm-id1",
+				"com.docker.swarm.id": "swarm1-id",
 			},
 		}),
 	}
 
 	container2 := &cluster.Container{
 		Container: dockerclient.Container{
-			Id:    "container-id2",
+			Id:    "container2-id",
 			Names: []string{"/con"},
 		},
 		Config: cluster.BuildContainerConfig(dockerclient.ContainerConfig{
 			Labels: map[string]string{
-				"com.docker.swarm.id": "swarm-id2",
+				"com.docker.swarm.id": "swarm2-id",
 			},
 		}),
 	}
@@ -56,9 +56,10 @@ func TestContainerLookup(t *testing.T) {
 	assert.Nil(t, c.Container("invalid-id"))
 	assert.Nil(t, c.Container(""))
 	// Container ID lookup.
-	assert.NotNil(t, c.Container("container-id1"))
+	assert.NotNil(t, c.Container("container1-id"))
 	// Container ID prefix lookup.
-	assert.NotNil(t, c.Container("container-"))
+	assert.NotNil(t, c.Container("container1-"))
+	assert.Nil(t, c.Container("container"))
 	// Container name lookup.
 	assert.NotNil(t, c.Container("container1-name1"))
 	assert.NotNil(t, c.Container("container1-name2"))
@@ -66,11 +67,12 @@ func TestContainerLookup(t *testing.T) {
 	assert.NotNil(t, c.Container("test-engine/container1-name1"))
 	assert.NotNil(t, c.Container("test-engine/container1-name2"))
 	// Swarm ID lookup.
-	assert.NotNil(t, c.Container("swarm-id1"))
+	assert.NotNil(t, c.Container("swarm1-id"))
 	// Swarm ID prefix lookup.
-	assert.NotNil(t, c.Container("swarm-"))
+	assert.NotNil(t, c.Container("swarm1-"))
+	assert.Nil(t, c.Container("swarm"))
 	// Match name before ID prefix
 	cc := c.Container("con")
 	assert.NotNil(t, cc)
-	assert.Equal(t, cc.Id, "container-id2")
+	assert.Equal(t, cc.Id, "container2-id")
 }