Merge pull request #991 from hashicorp/b-autoscale-lc-update

providers/aws: allow in-place update of launch configuration

builtin/providers/aws/resource_aws_autoscaling_group.go

@@ -29,7 +29,6 @@ func resourceAwsAutoscalingGroup() *schema.Resource {
 			"launch_configuration": &schema.Schema{
 				Type:     schema.TypeString,
 				Required: true,
-				ForceNew: true,
 			},
 
 			"desired_capacity": &schema.Schema{
@@ -150,17 +149,17 @@ func resourceAwsAutoscalingGroupCreate(d *schema.ResourceData, meta interface{})
 		autoScalingGroupOpts.SetHealthCheckGracePeriod = true
 	}
 
-	if v, ok := d.GetOk("load_balancers"); ok {
+	if v, ok := d.GetOk("load_balancers"); ok && v.(*schema.Set).Len() > 0 {
 		autoScalingGroupOpts.LoadBalancerNames = expandStringList(
 			v.(*schema.Set).List())
 	}
 
-	if v, ok := d.GetOk("vpc_zone_identifier"); ok {
+	if v, ok := d.GetOk("vpc_zone_identifier"); ok && v.(*schema.Set).Len() > 0 {
 		autoScalingGroupOpts.VPCZoneIdentifier = expandStringList(
 			v.(*schema.Set).List())
 	}
 
-	if v, ok := d.GetOk("termination_policies"); ok {
+	if v, ok := d.GetOk("termination_policies"); ok && v.(*schema.Set).Len() > 0 {
 		autoScalingGroupOpts.TerminationPolicies = expandStringList(
 			v.(*schema.Set).List())
 	}
@@ -214,6 +213,10 @@ func resourceAwsAutoscalingGroupUpdate(d *schema.ResourceData, meta interface{})
 		opts.SetDesiredCapacity = true
 	}
 
+	if d.HasChange("launch_configuration") {
+		opts.LaunchConfigurationName = d.Get("launch_configuration").(string)
+	}
+
 	if d.HasChange("min_size") {
 		opts.MinSize = d.Get("min_size").(int)
 		opts.SetMinSize = true

builtin/providers/aws/resource_aws_autoscaling_group_test.go

@@ -11,6 +11,7 @@ import (
 
 func TestAccAWSAutoScalingGroup_basic(t *testing.T) {
 	var group autoscaling.AutoScalingGroup
+	var lc autoscaling.LaunchConfiguration
 
 	resource.Test(t, resource.TestCase{
 		PreCheck:     func() { testAccPreCheck(t) },
@@ -47,8 +48,11 @@ func TestAccAWSAutoScalingGroup_basic(t *testing.T) {
 				Config: testAccAWSAutoScalingGroupConfigUpdate,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSAutoScalingGroupExists("aws_autoscaling_group.bar", &group),
+					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.new", &lc),
 					resource.TestCheckResourceAttr(
 						"aws_autoscaling_group.bar", "desired_capacity", "5"),
+					resource.TestCheckResourceAttrPtr(
+						"aws_autoscaling_group.bar", "launch_configuration", &lc.Name),
 				),
 			},
 		},
@@ -217,6 +221,12 @@ resource "aws_launch_configuration" "foobar" {
   instance_type = "t1.micro"
 }
 
+resource "aws_launch_configuration" "new" {
+  name = "foobarautoscaling-terraform-test-new"
+  image_id = "ami-21f78e11"
+  instance_type = "t1.micro"
+}
+
 resource "aws_autoscaling_group" "bar" {
   availability_zones = ["us-west-2a"]
   name = "foobar3-terraform-test"
@@ -227,7 +237,7 @@ resource "aws_autoscaling_group" "bar" {
   desired_capacity = 5
   force_delete = true
 
-  launch_configuration = "${aws_launch_configuration.foobar.name}"
+  launch_configuration = "${aws_launch_configuration.new.name}"
 }
 `
 

helper/resource/testing.go

@@ -275,6 +275,15 @@ func TestCheckResourceAttr(name, key, value string) TestCheckFunc {
 	}
 }
 
+// TestCheckResourceAttrPtr is like TestCheckResourceAttr except the
+// value is a pointer so that it can be updated while the test is running.
+// It will only be dereferenced at the point this step is run.
+func TestCheckResourceAttrPtr(name string, key string, value *string) TestCheckFunc {
+	return func(s *terraform.State) error {
+		return TestCheckResourceAttr(name, key, *value)(s)
+	}
+}
+
 // TestT is the interface used to handle the test lifecycle of a test.
 //
 // Users should just use a *testing.T object, which implements this.

helper/schema/resource_data.go

@@ -70,13 +70,14 @@ func (d *ResourceData) GetChange(key string) (interface{}, interface{}) {
 }
 
 // GetOk returns the data for the given key and whether or not the key
-// has been set.
+// has been set to a non-zero value at some point.
 //
 // The first result will not necessarilly be nil if the value doesn't exist.
 // The second result should be checked to determine this information.
 func (d *ResourceData) GetOk(key string) (interface{}, bool) {
 	r := d.getRaw(key, getSourceSet)
-	return r.Value, r.Exists && !r.Computed
+	exists := r.Exists && !r.Computed
+	return r.Value, exists
 }
 
 func (d *ResourceData) getRaw(key string, level getSource) getResult {
@@ -361,11 +362,13 @@ func (d *ResourceData) get(addr []string, source getSource) getResult {
 	}
 
 	// If the result doesn't exist, then we set the value to the zero value
-	if result.Value == nil {
-		if schemaL := addrToSchema(addr, d.schema); len(schemaL) > 0 {
-			schema := schemaL[len(schemaL)-1]
-			result.Value = result.ValueOrZero(schema)
-		}
+	var schema *Schema
+	if schemaL := addrToSchema(addr, d.schema); len(schemaL) > 0 {
+		schema = schemaL[len(schemaL)-1]
+	}
+
+	if result.Value == nil && schema != nil {
+		result.Value = result.ValueOrZero(schema)
 	}
 
 	// Transform the FieldReadResult into a getResult. It might be worth
@@ -375,5 +378,6 @@ func (d *ResourceData) get(addr []string, source getSource) getResult {
 		ValueProcessed: result.ValueProcessed,
 		Computed:       result.Computed,
 		Exists:         result.Exists,
+		Schema:         schema,
 	}
 }