move region validation to run so that we don't break validation when we don't have aws creds set

builder/amazon/common/access_config.go

@@ -162,13 +162,6 @@ func (c *AccessConfig) Prepare(ctx *interpolate.Context) []error {
 			fmt.Errorf("`access_key` and `secret_key` must both be either set or not set."))
 	}
 
-	if c.RawRegion != "" && !c.SkipValidation {
-		err := c.ValidateRegion(c.RawRegion)
-		if err != nil {
-			errs = append(errs, fmt.Errorf("error validating region: %s", err.Error()))
-		}
-	}
-
 	return errs
 }
 

builder/amazon/common/ami_config.go

@@ -96,14 +96,6 @@ func (c *AMIConfig) Prepare(accessConfig *AccessConfig, ctx *interpolate.Context
 
 func (c *AMIConfig) prepareRegions(accessConfig *AccessConfig) (errs []error) {
 	if len(c.AMIRegions) > 0 {
-		if !c.AMISkipRegionValidation {
-			// Verify the regions are real
-			err := accessConfig.ValidateRegion(c.AMIRegions...)
-			if err != nil {
-				errs = append(errs, fmt.Errorf("error validating regions: %v", err))
-			}
-		}
-
 		regionSet := make(map[string]struct{})
 		regions := make([]string, 0, len(c.AMIRegions))
 

builder/amazon/ebs/builder.go

@@ -86,11 +86,17 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 }
 
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {
-
 	session, err := b.config.Session()
 	if err != nil {
 		return nil, err
 	}
+	if !b.config.AMISkipRegionValidation {
+		regionsToValidate := append(b.config.AMIRegions, b.config.RawRegion)
+		err := b.config.AccessConfig.ValidateRegion(regionsToValidate...)
+		if err != nil {
+			return nil, fmt.Errorf("error validating regions: %v", err)
+		}
+	}
 	ec2conn := ec2.New(session)
 
 	// Setup the state bag and initial state for the steps