kubernetes: Do kubernetes_pod diff-ing via CompareFunc (WIP)

builtin/providers/kubernetes/resource_pod.go

@@ -2,10 +2,13 @@ package kubernetes
 
 import (
 	"encoding/json"
+	"fmt"
 	"log"
+	"reflect"
 	"strings"
 
 	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/terraform"
 	"k8s.io/kubernetes/pkg/api"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
 	"k8s.io/kubernetes/pkg/util/yaml"
@@ -38,8 +41,9 @@ func resourceKubernetesPod() *schema.Resource {
 			},
 
 			"spec": &schema.Schema{
-				Type:     schema.TypeString,
-				Required: true,
+				Type:        schema.TypeString,
+				Required:    true,
+				CompareFunc: compareNonEmptyFields,
 				StateFunc: func(input interface{}) string {
 					s, err := normalizePodSpec(input.(string))
 					if err != nil {
@@ -162,7 +166,7 @@ func flattenPodSpec(spec api.PodSpec) (string, error) {
 		return "", err
 	}
 
-	return string(b), nil
+	return normalizePodSpec(string(b))
 }
 
 func normalizePodSpec(input string) (string, error) {
@@ -175,12 +179,46 @@ func normalizePodSpec(input string) (string, error) {
 		return "", err
 	}
 
-	// TODO: Add/ignore default structures, e.g. resources.limits.cpu = 100m
-
 	b, err := json.Marshal(spec)
 	if err != nil {
 		return "", err
 	}
 
 	return string(b), nil
 }
+
+func compareNonEmptyFields(o, n string) (*terraform.ResourceAttrDiff, error) {
+	oo := &api.PodSpec{}
+	json.Unmarshal([]byte(o), &oo)
+
+	no := &api.PodSpec{}
+	json.Unmarshal([]byte(n), &no)
+
+	err := stripUndefinedFieldsFromNew(oo, no)
+	if err != nil {
+		return nil, err
+	}
+
+	old_s, err := json.Marshal(oo)
+	if err != nil {
+		return nil, err
+	}
+	new_s, err := json.Marshal(no)
+	if err != nil {
+		return nil, err
+	}
+
+	if !reflect.DeepEqual(oo, no) {
+		return &terraform.ResourceAttrDiff{
+			Old: string(old_s),
+			New: string(new_s),
+		}, nil
+	}
+	return nil, nil
+
+}
+
+func stripUndefinedFieldsFromNew(o, n *api.PodSpec) error {
+	// TODO
+	return nil
+}