From e0f229d2caa4a46f06a327deffcfea80fceff915 Mon Sep 17 00:00:00 2001
From: Yong Tang <yong.tang.github@outlook.com>
Date: Thu, 25 Aug 2016 21:08:53 -0700
Subject: [PATCH] Let swarmkit handle cluster defaults in `swarm init` if not
 specified

This fix tries to address the issue raised in 24958 where previously
`docker swarm init` will automatically fill in all the default value
(instead of letting swarmkit to handle the default).

This fix update the `swarm init` so that initial value are passed only
when a flag change has been detected.

This fix fixes 24958.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
---
 command/swarm/init.go   |  2 +-
 command/swarm/opts.go   | 19 ++++++++++++++-----
 command/swarm/update.go |  3 ++-
 command/system/info.go  |  6 +++++-
 4 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/command/swarm/init.go b/command/swarm/init.go
index 9a17224bde..60fb8e8fe3 100644
--- a/command/swarm/init.go
+++ b/command/swarm/init.go
@@ -59,7 +59,7 @@ func runInit(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts initOption
 		ListenAddr:      opts.listenAddr.String(),
 		AdvertiseAddr:   opts.advertiseAddr,
 		ForceNewCluster: opts.forceNewCluster,
-		Spec:            opts.swarmOptions.ToSpec(),
+		Spec:            opts.swarmOptions.ToSpec(flags),
 	}
 
 	nodeID, err := client.SwarmInit(ctx, req)
diff --git a/command/swarm/opts.go b/command/swarm/opts.go
index 7fcf25d136..58330b7f8a 100644
--- a/command/swarm/opts.go
+++ b/command/swarm/opts.go
@@ -169,11 +169,20 @@ func addSwarmFlags(flags *pflag.FlagSet, opts *swarmOptions) {
 	flags.Var(&opts.externalCA, flagExternalCA, "Specifications of one or more certificate signing endpoints")
 }
 
-func (opts *swarmOptions) ToSpec() swarm.Spec {
+func (opts *swarmOptions) ToSpec(flags *pflag.FlagSet) swarm.Spec {
 	spec := swarm.Spec{}
-	spec.Orchestration.TaskHistoryRetentionLimit = opts.taskHistoryLimit
-	spec.Dispatcher.HeartbeatPeriod = opts.dispatcherHeartbeat
-	spec.CAConfig.NodeCertExpiry = opts.nodeCertExpiry
-	spec.CAConfig.ExternalCAs = opts.externalCA.Value()
+
+	if flags.Changed(flagTaskHistoryLimit) {
+		spec.Orchestration.TaskHistoryRetentionLimit = &opts.taskHistoryLimit
+	}
+	if flags.Changed(flagDispatcherHeartbeat) {
+		spec.Dispatcher.HeartbeatPeriod = opts.dispatcherHeartbeat
+	}
+	if flags.Changed(flagCertExpiry) {
+		spec.CAConfig.NodeCertExpiry = opts.nodeCertExpiry
+	}
+	if flags.Changed(flagExternalCA) {
+		spec.CAConfig.ExternalCAs = opts.externalCA.Value()
+	}
 	return spec
 }
diff --git a/command/swarm/update.go b/command/swarm/update.go
index 9884b79169..71451e450c 100644
--- a/command/swarm/update.go
+++ b/command/swarm/update.go
@@ -58,7 +58,8 @@ func mergeSwarm(swarm *swarm.Swarm, flags *pflag.FlagSet) error {
 	spec := &swarm.Spec
 
 	if flags.Changed(flagTaskHistoryLimit) {
-		spec.Orchestration.TaskHistoryRetentionLimit, _ = flags.GetInt64(flagTaskHistoryLimit)
+		taskHistoryRetentionLimit, _ := flags.GetInt64(flagTaskHistoryLimit)
+		spec.Orchestration.TaskHistoryRetentionLimit = &taskHistoryRetentionLimit
 	}
 
 	if flags.Changed(flagDispatcherHeartbeat) {
diff --git a/command/system/info.go b/command/system/info.go
index a2d0abad23..1debf755f1 100644
--- a/command/system/info.go
+++ b/command/system/info.go
@@ -107,7 +107,11 @@ func prettyPrintInfo(dockerCli *command.DockerCli, info types.Info) error {
 			fmt.Fprintf(dockerCli.Out(), " Managers: %d\n", info.Swarm.Managers)
 			fmt.Fprintf(dockerCli.Out(), " Nodes: %d\n", info.Swarm.Nodes)
 			fmt.Fprintf(dockerCli.Out(), " Orchestration:\n")
-			fmt.Fprintf(dockerCli.Out(), "  Task History Retention Limit: %d\n", info.Swarm.Cluster.Spec.Orchestration.TaskHistoryRetentionLimit)
+			taskHistoryRetentionLimit := int64(0)
+			if info.Swarm.Cluster.Spec.Orchestration.TaskHistoryRetentionLimit != nil {
+				taskHistoryRetentionLimit = *info.Swarm.Cluster.Spec.Orchestration.TaskHistoryRetentionLimit
+			}
+			fmt.Fprintf(dockerCli.Out(), "  Task History Retention Limit: %d\n", taskHistoryRetentionLimit)
 			fmt.Fprintf(dockerCli.Out(), " Raft:\n")
 			fmt.Fprintf(dockerCli.Out(), "  Snapshot Interval: %d\n", info.Swarm.Cluster.Spec.Raft.SnapshotInterval)
 			fmt.Fprintf(dockerCli.Out(), "  Heartbeat Tick: %d\n", info.Swarm.Cluster.Spec.Raft.HeartbeatTick)