Add Node Labels to Cluster Info information

Updates: docker info output and /info API
Check for labels in API integration tests

Signed-off-by: Sriram Natarajan <natarajan.sriram@gmail.com>

cluster/swarm/cluster.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"sort"
+	"strings"
 	"sync"
 
 	log "github.com/Sirupsen/logrus"
@@ -310,6 +311,12 @@ func (c *Cluster) Info() [][2]string {
 		info = append(info, [2]string{" └ Containers", fmt.Sprintf("%d", len(engine.Containers()))})
 		info = append(info, [2]string{" └ Reserved CPUs", fmt.Sprintf("%d / %d", engine.UsedCpus(), engine.TotalCpus())})
 		info = append(info, [2]string{" └ Reserved Memory", fmt.Sprintf("%s / %s", units.BytesSize(float64(engine.UsedMemory())), units.BytesSize(float64(engine.TotalMemory())))})
+		labels := make([]string, 0, len(engine.Labels))
+		for k, v := range engine.Labels {
+			labels = append(labels, k+"="+v)
+		}
+		sort.Strings(labels)
+		info = append(info, [2]string{" └ Labels", fmt.Sprintf("%s", strings.Join(labels, ", "))})
 	}
 
 	return info

test/integration/api.bats

@@ -114,11 +114,12 @@ function teardown() {
 }
 
 @test "docker info" {
-	start_docker 3
+	start_docker 1 --label foo=bar
 	swarm_manage
 	run docker_swarm info
 	[ "$status" -eq 0 ]
-	[[ "${lines[3]}" == *"Nodes: 3" ]]
+	[[ "${lines[3]}" == *"Nodes: 1" ]]
+	[[ "${output}" == *"└ Labels:"*"foo=bar"* ]]
 }
 
 # FIXME