From 3894254dddc56bf283d7361dc88953a167a3be1f Mon Sep 17 00:00:00 2001
From: Aaron Lehmann <aaron.lehmann@docker.com>
Date: Tue, 28 Mar 2017 14:20:25 -0700
Subject: [PATCH] api: Omit Cluster, Nodes, and Managers from swarm info when
 unavailable

Currently these fields are included in the response JSON with zero
values. It's better not to include them if the information is
unavailable (for example, on a worker node).

This turns Cluster into a pointer so that it can be left out.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
---
 api/types/swarm/swarm.go   | 6 +++---
 cli/command/system/info.go | 2 +-
 daemon/cluster/swarm.go    | 3 +--
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/api/types/swarm/swarm.go b/api/types/swarm/swarm.go
index 549671ea43..c513274750 100644
--- a/api/types/swarm/swarm.go
+++ b/api/types/swarm/swarm.go
@@ -179,10 +179,10 @@ type Info struct {
 	Error            string
 
 	RemoteManagers []Peer
-	Nodes          int
-	Managers       int
+	Nodes          int `json:",omitempty"`
+	Managers       int `json:",omitempty"`
 
-	Cluster ClusterInfo
+	Cluster *ClusterInfo `json:",omitempty"`
 }
 
 // Peer represents a peer.
diff --git a/cli/command/system/info.go b/cli/command/system/info.go
index 448fc30514..8498dd8c55 100644
--- a/cli/command/system/info.go
+++ b/cli/command/system/info.go
@@ -97,7 +97,7 @@ func prettyPrintInfo(dockerCli *command.DockerCli, info types.Info) error {
 			fmt.Fprintf(dockerCli.Out(), " Error: %v\n", info.Swarm.Error)
 		}
 		fmt.Fprintf(dockerCli.Out(), " Is Manager: %v\n", info.Swarm.ControlAvailable)
-		if info.Swarm.ControlAvailable && info.Swarm.Error == "" && info.Swarm.LocalNodeState != swarm.LocalNodeStateError {
+		if info.Swarm.Cluster != nil && info.Swarm.ControlAvailable && info.Swarm.Error == "" && info.Swarm.LocalNodeState != swarm.LocalNodeStateError {
 			fmt.Fprintf(dockerCli.Out(), " ClusterID: %s\n", info.Swarm.Cluster.ID)
 			fmt.Fprintf(dockerCli.Out(), " Managers: %d\n", info.Swarm.Managers)
 			fmt.Fprintf(dockerCli.Out(), " Nodes: %d\n", info.Swarm.Nodes)
diff --git a/daemon/cluster/swarm.go b/daemon/cluster/swarm.go
index 84c8582fcd..3e01a99cfc 100644
--- a/daemon/cluster/swarm.go
+++ b/daemon/cluster/swarm.go
@@ -407,8 +407,7 @@ func (c *Cluster) Info() types.Info {
 			info.Error = err.Error()
 		}
 
-		// Strip JoinTokens
-		info.Cluster = swarm.ClusterInfo
+		info.Cluster = &swarm.ClusterInfo
 
 		if r, err := state.controlClient.ListNodes(ctx, &swarmapi.ListNodesRequest{}); err != nil {
 			info.Error = err.Error()