helper/resource: nice helper for resourceprovider impl

builtin/providers/aws/refresh.go

@@ -1,31 +0,0 @@
-package aws
-
-import (
-	"github.com/hashicorp/terraform/terraform"
-)
-
-// RefreshFunc is a function that performs a refresh of a specific type
-// of resource.
-type RefreshFunc func(
-	*ResourceProvider,
-	*terraform.ResourceState) (*terraform.ResourceState, error)
-
-// refreshMap keeps track of all the resources that this provider
-// can refresh.
-var refreshMap map[string]RefreshFunc
-
-func init() {
-	refreshMap = map[string]RefreshFunc{
-		"aws_instance": refresh_aws_instance,
-	}
-}
-
-func refresh_aws_instance(
-	p *ResourceProvider,
-	s *terraform.ResourceState) (*terraform.ResourceState, error) {
-	if s.ID != "" {
-		panic("OH MY WOW")
-	}
-
-	return s, nil
-}

builtin/providers/aws/resource_provider.go

@@ -54,16 +54,7 @@ func (p *ResourceProvider) Configure(c *terraform.ResourceConfig) error {
 func (p *ResourceProvider) Apply(
 	s *terraform.ResourceState,
 	d *terraform.ResourceDiff) (*terraform.ResourceState, error) {
-	result := &terraform.ResourceState{
+	return resourceMap.Apply(s, d, p)
-		ID: "foo",
-	}
-	result = result.MergeDiff(d)
-	result.Attributes["public_dns"] = "foo"
-	result.Attributes["public_ip"] = "foo"
-	result.Attributes["private_dns"] = "foo"
-	result.Attributes["private_ip"] = "foo"
-
-	return result, nil
 }
 
 func (p *ResourceProvider) Diff(
@@ -79,24 +70,9 @@ func (p *ResourceProvider) Diff(
 
 func (p *ResourceProvider) Refresh(
 	s *terraform.ResourceState) (*terraform.ResourceState, error) {
-	// If there isn't an ID previously, then the thing didn't exist,
+	return resourceMap.Refresh(s, p)
-	// so there is nothing to refresh.
-	if s.ID == "" {
-		return s, nil
-	}
-
-	f, ok := refreshMap[s.Type]
-	if !ok {
-		return s, fmt.Errorf("Unknown resource type: %s", s.Type)
-	}
-
-	return f(p, s)
 }
 
 func (p *ResourceProvider) Resources() []terraform.ResourceType {
-	return []terraform.ResourceType{
+	return resourceMap.Resources()
-		terraform.ResourceType{
-			Name: "aws_instance",
-		},
-	}
 }

builtin/providers/aws/resources.go

@@ -0,0 +1,66 @@
+package aws
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+	"github.com/mitchellh/goamz/ec2"
+)
+
+var resourceMap *resource.Map
+
+func init() {
+	resourceMap = &resource.Map{
+		Mapping: map[string]resource.Resource{
+			"aws_instance": resource.Resource{
+				Create:  resource_aws_instance_create,
+				Refresh: resource_aws_instance_refresh,
+			},
+		},
+	}
+}
+
+func resource_aws_instance_create(
+	s *terraform.ResourceState,
+	d *terraform.ResourceDiff,
+	meta interface{}) (*terraform.ResourceState, error) {
+	p := meta.(*ResourceProvider)
+	ec2conn := p.ec2conn
+
+	runOpts := &ec2.RunInstances{
+		ImageId:      d.Attributes["ami"].New,
+		InstanceType: d.Attributes["instance_type"].New,
+	}
+
+	log.Printf("Run configuration: %#v", runOpts)
+	runResp, err := ec2conn.RunInstances(runOpts)
+	if err != nil {
+		return nil, fmt.Errorf("Error launching source instance: %s", err)
+	}
+
+	instance := &runResp.Instances[0]
+	log.Printf("Instance ID: %s", instance.InstanceId)
+
+	// TODO(mitchellh): wait until running
+
+	rs := s.MergeDiff(d)
+	rs.ID = instance.InstanceId
+	rs.Attributes["public_dns"] = instance.DNSName
+	rs.Attributes["public_ip"] = instance.PublicIpAddress
+	rs.Attributes["private_dns"] = instance.PrivateDNSName
+	rs.Attributes["private_ip"] = instance.PrivateIpAddress
+
+	return rs, nil
+}
+
+func resource_aws_instance_refresh(
+	s *terraform.ResourceState,
+	meta interface{}) (*terraform.ResourceState, error) {
+	if s.ID != "" {
+		panic("OH MY WOW")
+	}
+
+	return s, nil
+}

helper/resource/map.go

@@ -0,0 +1,68 @@
+package resource
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/terraform/terraform"
+)
+
+// Map is a map of resources that are supported, and provides helpers for
+// more easily implementing a ResourceProvider.
+type Map struct {
+	Mapping map[string]Resource
+}
+
+// Apply performs a create or update depending on the diff, and calls
+// the proper function on the matching Resource.
+func (m *Map) Apply(
+	s *terraform.ResourceState,
+	d *terraform.ResourceDiff,
+	meta interface{}) (*terraform.ResourceState, error) {
+	r, ok := m.Mapping[s.Type]
+	if !ok {
+		return nil, fmt.Errorf("Unknown resource type: %s", s.Type)
+	}
+
+	if s.ID == "" {
+		return r.Create(s, d, meta)
+	} else {
+		panic("update no implemented yet")
+		//return r.Update(s, d, meta)
+	}
+}
+
+// Refresh performs a Refresh on the proper resource type.
+//
+// Refresh on the Resource won't be called if the state represents a
+// non-created resource (ID is blank).
+//
+// An error is returned if the resource isn't registered.
+func (m *Map) Refresh(
+	s *terraform.ResourceState,
+	meta interface{}) (*terraform.ResourceState, error) {
+	// If the resource isn't created, don't refresh.
+	if s.ID == "" {
+		return s, nil
+	}
+
+	r, ok := m.Mapping[s.Type]
+	if !ok {
+		return nil, fmt.Errorf("Unknown resource type: %s", s.Type)
+	}
+
+	return r.Refresh(s, meta)
+}
+
+// Resources returns all the resources that are supported by this
+// resource map and can be used to satisfy the Resources method of
+// a ResourceProvider.
+func (m *Map) Resources() []terraform.ResourceType {
+	rs := make([]terraform.ResourceType, 0, len(m.Mapping))
+	for k, _ := range m.Mapping {
+		rs = append(rs, terraform.ResourceType{
+			Name: k,
+		})
+	}
+
+	return rs
+}

helper/resource/resource.go

@@ -0,0 +1,30 @@
+package resource
+
+import (
+	"github.com/hashicorp/terraform/terraform"
+)
+
+type Resource struct {
+	Create  CreateFunc
+	Diff    DiffFunc
+	Refresh RefreshFunc
+}
+
+// CreateFunc is a function that creates a resource that didn't previously
+// exist.
+type CreateFunc func(
+	*terraform.ResourceState,
+	*terraform.ResourceDiff,
+	interface{}) (*terraform.ResourceState, error)
+
+// DiffFunc is a function that performs a diff of a resource.
+type DiffFunc func(
+	*terraform.ResourceState,
+	*terraform.ResourceConfig,
+	interface{}) (*terraform.ResourceDiff, error)
+
+// RefreshFunc is a function that performs a refresh of a specific type
+// of resource.
+type RefreshFunc func(
+	*terraform.ResourceState,
+	interface{}) (*terraform.ResourceState, error)