terraform: Adding lifecycle config block

config/config.go

@@ -54,13 +54,19 @@ type ProviderConfig struct {
 // A Terraform resource is something that represents some component that
 // can be created and managed, and has some properties associated with it.
 type Resource struct {
-	Name                string
-	Type                string
-	Count               int
-	RawConfig           *RawConfig
-	Provisioners        []*Provisioner
-	DependsOn           []string
-	CreateBeforeDestroy bool
+	Name         string
+	Type         string
+	Count        int
+	RawConfig    *RawConfig
+	Provisioners []*Provisioner
+	DependsOn    []string
+	Lifecycle    ResourceLifecycle
+}
+
+// ResourceLifecycle is used to store the lifecycle tuning parameters
+// to allow customized behavior
+type ResourceLifecycle struct {
+	CreateBeforeDestroy bool `hcl:"create_before_destroy"`
 }
 
 // Provisioner is a configured provisioner step on a resource.

config/loader_hcl.go

@@ -394,7 +394,7 @@ func loadResourcesHcl(os *hclobj.Object) ([]*Resource, error) {
 			delete(config, "count")
 			delete(config, "depends_on")
 			delete(config, "provisioner")
-			delete(config, "create_before_destroy")
+			delete(config, "lifecycle")
 
 			rawConfig, err := NewRawConfig(config)
 			if err != nil {
@@ -460,12 +460,12 @@ func loadResourcesHcl(os *hclobj.Object) ([]*Resource, error) {
 
 			// Check if the resource should be re-created before
 			// destroying the existing instance
-			var createBeforeDestroy bool
-			if o := obj.Get("create_before_destroy", false); o != nil {
-				err = hcl.DecodeObject(&createBeforeDestroy, o)
+			var lifecycle ResourceLifecycle
+			if o := obj.Get("lifecycle", false); o != nil {
+				err = hcl.DecodeObject(&lifecycle, o)
 				if err != nil {
 					return nil, fmt.Errorf(
-						"Error parsing create_before_destroy for %s[%s]: %s",
+						"Error parsing lifecycle for %s[%s]: %s",
 						t.Key,
 						k,
 						err)
@@ -473,13 +473,13 @@ func loadResourcesHcl(os *hclobj.Object) ([]*Resource, error) {
 			}
 
 			result = append(result, &Resource{
-				Name:                k,
-				Type:                t.Key,
-				Count:               count,
-				RawConfig:           rawConfig,
-				Provisioners:        provisioners,
-				DependsOn:           dependsOn,
-				CreateBeforeDestroy: createBeforeDestroy,
+				Name:         k,
+				Type:         t.Key,
+				Count:        count,
+				RawConfig:    rawConfig,
+				Provisioners: provisioners,
+				DependsOn:    dependsOn,
+				Lifecycle:    lifecycle,
 			})
 		}
 	}

config/loader_test.go

@@ -368,7 +368,7 @@ func TestLoad_createBeforeDestroy(t *testing.T) {
 	}
 
 	// Should enable create before destroy
-	if !r.CreateBeforeDestroy {
+	if !r.Lifecycle.CreateBeforeDestroy {
 		t.Fatalf("Bad: %#v", r)
 	}
 
@@ -378,7 +378,7 @@ func TestLoad_createBeforeDestroy(t *testing.T) {
 	}
 
 	// Should not enable create before destroy
-	if r.CreateBeforeDestroy {
+	if r.Lifecycle.CreateBeforeDestroy {
 		t.Fatalf("Bad: %#v", r)
 	}
 }

config/test-fixtures/create-before-destroy.tf

@@ -1,10 +1,14 @@
 
 resource "aws_instance" "web" {
     ami = "foo"
-    create_before_destroy = true
+    lifecycle {
+        create_before_destroy = true
+    }
 }
 
 resource "aws_instance" "bar" {
     ami = "foo"
-    create_before_destroy = false
+    lifecycle {
+        create_before_destroy = false
+    }
 }

terraform/graph.go

@@ -534,7 +534,7 @@ func graphAddDiff(g *depgraph.Graph, d *ModuleDiff) error {
 			// The dependency ordering depends on if the CreateBeforeDestroy
 			// flag is enabled. If so, we must create the replacement first,
 			// and then destroy the old instance.
-			if rn.Config != nil && rn.Config.CreateBeforeDestroy && !rd.Empty() {
+			if rn.Config != nil && rn.Config.Lifecycle.CreateBeforeDestroy && !rd.Empty() {
 				dep := &depgraph.Dependency{
 					Name:   n.Name,
 					Source: newN,

terraform/test-fixtures/graph-diff-create-before/main.tf

@@ -2,5 +2,7 @@ provider "aws" {}
 
 resource "aws_instance" "bar" {
     ami = "abc"
-    create_before_destroy = true
+    lifecycle {
+        create_before_destroy = true
+    }
 }