add better generate

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/cli/kubernetes/labels/labels.go

@@ -0,0 +1,58 @@
+package labels
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	// ForServiceName is the label for the service name.
+	ForServiceName = "com.docker.service.name"
+	// ForStackName is the label for the stack name.
+	ForStackName = "com.docker.stack.namespace"
+	// ForServiceID is the label for the service id.
+	ForServiceID = "com.docker.service.id"
+)
+
+// ForService gives the labels to select a given service in a stack.
+func ForService(stackName, serviceName string) map[string]string {
+	labels := map[string]string{}
+
+	if serviceName != "" {
+		labels[ForServiceName] = serviceName
+	}
+	if stackName != "" {
+		labels[ForStackName] = stackName
+	}
+	if serviceName != "" && stackName != "" {
+		labels[ForServiceID] = stackName + "-" + serviceName
+	}
+
+	return labels
+}
+
+// Merge merges multiple lists of labels.
+func Merge(labelsList ...map[string]string) map[string]string {
+	merged := map[string]string{}
+
+	for _, labels := range labelsList {
+		for k, v := range labels {
+			merged[k] = v
+		}
+	}
+
+	return merged
+}
+
+// SelectorForStack gives the labelSelector to use for a given stack.
+// Specific service names can be passed to narrow down the selection.
+func SelectorForStack(stackName string, serviceNames ...string) string {
+	switch len(serviceNames) {
+	case 0:
+		return fmt.Sprintf("%s=%s", ForStackName, stackName)
+	case 1:
+		return fmt.Sprintf("%s=%s,%s=%s", ForStackName, stackName, ForServiceName, serviceNames[0])
+	default:
+		return fmt.Sprintf("%s=%s,%s in (%s)", ForStackName, stackName, ForServiceName, strings.Join(serviceNames, ","))
+	}
+}

vendor/github.com/docker/cli/kubernetes/labels/labels_test.go

@@ -0,0 +1,23 @@
+package labels
+
+import (
+	"testing"
+
+	"github.com/gotestyourself/gotestyourself/assert"
+	is "github.com/gotestyourself/gotestyourself/assert/cmp"
+)
+
+func TestForService(t *testing.T) {
+	labels := ForService("stack", "service")
+
+	assert.Check(t, is.Len(labels, 3))
+	assert.Check(t, is.Equal("stack", labels["com.docker.stack.namespace"]))
+	assert.Check(t, is.Equal("service", labels["com.docker.service.name"]))
+	assert.Check(t, is.Equal("stack-service", labels["com.docker.service.id"]))
+}
+
+func TestSelectorForStack(t *testing.T) {
+	assert.Check(t, is.Equal("com.docker.stack.namespace=demostack", SelectorForStack("demostack")))
+	assert.Check(t, is.Equal("com.docker.stack.namespace=stack,com.docker.service.name=service", SelectorForStack("stack", "service")))
+	assert.Check(t, is.Equal("com.docker.stack.namespace=stack,com.docker.service.name in (service1,service2)", SelectorForStack("stack", "service1", "service2")))
+}