builder/amazonebs: Finish basic validation

builder/amazonebs/builder.go

@@ -68,6 +68,10 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 		errs = append(errs, errors.New("An instance_type must be specified"))
 	}
 
+	if b.config.Region == "" {
+		errs = append(errs, errors.New("A region must be specified"))
+	}
+
 	if b.config.SSHUsername == "" {
 		errs = append(errs, errors.New("An ssh_username must be specified"))
 	}
@@ -76,9 +80,6 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 		return &packer.MultiError{errs}
 	}
 
-	// TODO: config validation and asking for fields:
-	// * region (exists and valid)
-
 	log.Printf("Config: %+v", b.config)
 	return
 }

builder/amazonebs/builder_test.go

@@ -11,6 +11,7 @@ func testConfig() map[string]interface{} {
 		"secret_key": "bar",
 		"source_ami": "foo",
 		"instance_type": "foo",
+		"region": "foo",
 		"ssh_username": "root",
 	}
 }
@@ -83,6 +84,30 @@ func TestBuilderPrepare_InstanceType(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_Region(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Test good
+	config["region"] = "foo"
+	err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	if b.config.Region != "foo" {
+		t.Errorf("invalid: %s", b.config.Region)
+	}
+
+	// Test bad
+	delete(config, "region")
+	b = Builder{}
+	err = b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+}
+
 func TestBuilderPrepare_SecretKey(t *testing.T) {
 	var b Builder
 	config := testConfig()