Fixed incorrect ForcesNew settings for parameters and added better acceptance tests to ensure updates are working as expected

builtin/providers/aws/resource_aws_db_parameter_group.go

@@ -37,7 +37,7 @@ func resourceAwsDbParameterGroup() *schema.Resource {
 			"parameter": &schema.Schema{
 				Type:     schema.TypeSet,
 				Optional: true,
-				ForceNew: true,
+				ForceNew: false,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						"apply_method": &schema.Schema{
@@ -85,6 +85,12 @@ func resourceAwsDbParameterGroupCreate(d *schema.ResourceData, meta interface{})
 		return fmt.Errorf("Error creating DB Parameter Group: %s", err)
 	}
 
+	d.Partial(true)
+	d.SetPartial("name")
+	d.SetPartial("family")
+	d.SetPartial("description")
+	d.Partial(false)
+
 	d.SetId(createOpts.DBParameterGroupName)
 	log.Printf("[INFO] DB Parameter Group ID: %s", d.Id())
 
@@ -95,6 +101,8 @@ func resourceAwsDbParameterGroupUpdate(d *schema.ResourceData, meta interface{})
 	p := meta.(*ResourceProvider)
 	rdsconn := p.rdsconn
 
+	d.Partial(true)
+
 	if d.HasChange("parameter") {
 		o, n := d.GetChange("parameter")
 		if o == nil {
@@ -125,9 +133,12 @@ func resourceAwsDbParameterGroupUpdate(d *schema.ResourceData, meta interface{})
 				return fmt.Errorf("Error modifying DB Parameter Group: %s", err)
 			}
 		}
+		d.SetPartial("parameter")
 	}
 
-	return nil
+	d.Partial(false)
+
+	return resourceAwsDbParameterGroupRead(d, meta)
 }
 
 func resourceAwsDbParameterGroupDelete(d *schema.ResourceData, meta interface{}) error {
@@ -175,6 +186,9 @@ func resourceAwsDbParameterGroupRead(d *schema.ResourceData, meta interface{}) e
 		return err
 	}
 
+	// apply_method is only relevant for creates and AWS does not maintain its state.
+
+
 	d.Set("parameter", flattenParameters(describeParametersResp.Parameters))
 
 	return nil

builtin/providers/aws/resource_aws_db_parameter_group_test.go

@@ -19,6 +19,31 @@ func TestAccAWSDBParameterGroup(t *testing.T) {
 		Steps: []resource.TestStep{
 			resource.TestStep{
 				Config: testAccAWSDBParameterGroupConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSDBParameterGroupExists("aws_db_parameter_group.bar", &v),
+					testAccCheckAWSDBParameterGroupAttributes(&v),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "name", "parameter-group-test-terraform"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "family", "mysql5.6"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "description", "Test parameter group for terraform"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.0.name", "character_set_results"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.0.value", "utf8"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.1.name", "character_set_server"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.1.value", "utf8"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.2.name", "character_set_client"),
+					resource.TestCheckResourceAttr(
+						"aws_db_parameter_group.bar", "parameter.2.value", "utf8"),
+				),
+			},
+			resource.TestStep{
+				Config: testAccAWSDBParameterGroupAddParametersConfig,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSDBParameterGroupExists("aws_db_parameter_group.bar", &v),
 					testAccCheckAWSDBParameterGroupAttributes(&v),
@@ -32,32 +57,22 @@ func TestAccAWSDBParameterGroup(t *testing.T) {
 						"aws_db_parameter_group.bar", "parameter.0.name", "collation_connection"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.0.value", "utf8_unicode_ci"),
-					resource.TestCheckResourceAttr(
-						"aws_db_parameter_group.bar", "parameter.0.apply_method", "immediate"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.1.name", "character_set_results"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.1.value", "utf8"),
-					resource.TestCheckResourceAttr(
-						"aws_db_parameter_group.bar", "parameter.1.apply_method", "immediate"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.2.name", "character_set_server"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.2.value", "utf8"),
-					resource.TestCheckResourceAttr(
-						"aws_db_parameter_group.bar", "parameter.2.apply_method", "immediate"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.3.name", "collation_server"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.3.value", "utf8_unicode_ci"),
-					resource.TestCheckResourceAttr(
-						"aws_db_parameter_group.bar", "parameter.3.apply_method", "immediate"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.4.name", "character_set_client"),
 					resource.TestCheckResourceAttr(
 						"aws_db_parameter_group.bar", "parameter.4.value", "utf8"),
-					resource.TestCheckResourceAttr(
-						"aws_db_parameter_group.bar", "parameter.4.apply_method", "immediate"),
 				),
 			},
 		},
@@ -177,6 +192,29 @@ func testAccCheckAWSDBParameterGroupExists(n string, v *rds.DBParameterGroup) re
 }
 
 const testAccAWSDBParameterGroupConfig = `
+resource "aws_db_parameter_group" "bar" {
+	name = "parameter-group-test-terraform"
+	family = "mysql5.6"
+	description = "Test parameter group for terraform"
+	parameter {
+	  name = "character_set_server"
+	  value = "utf8"
+	  apply_method = "immediate"
+	}
+	parameter {
+	  name = "character_set_client"
+	  value = "utf8"
+	  apply_method = "immediate"
+	}
+	parameter{
+	  name = "character_set_results"
+	  value = "utf8"
+	  apply_method = "immediate"
+	}
+}
+`
+
+const testAccAWSDBParameterGroupAddParametersConfig = `
 resource "aws_db_parameter_group" "bar" {
 	name = "parameter-group-test-terraform"
 	family = "mysql5.6"

builtin/providers/aws/structure.go

@@ -192,6 +192,9 @@ func flattenParameters(list []rds.Parameter) []map[string]interface{} {
 		result = append(result, map[string]interface{}{
 				"name":         strings.ToLower(i.ParameterName),
 				"value":        strings.ToLower(i.ParameterValue),
+				// apply_method is only used on create/modify and is not returned when reading from AWS.
+				// This is a dummy value to print out as it's not used when doing the state diff for updating
+				"apply_method": "applied",
 			})
 	}
 	return result

builtin/providers/aws/structure_test.go

@@ -299,6 +299,7 @@ func Test_flattenParameters(t *testing.T) {
 				map[string]interface{}{
 					"name":         "character_set_client",
 					"value":        "utf8",
+					"apply_method": "applied",
 				},
 			},
 		},