add an option custom_endpoint_ec2 for amazon builder, add a condition if vpc_id is empty don't add the parameter to the aws call

builder/amazon/common/access_config.go

@@ -17,12 +17,13 @@ import (
 
 // AccessConfig is for common configuration related to AWS access
 type AccessConfig struct {
-	AccessKey      string `mapstructure:"access_key"`
-	SecretKey      string `mapstructure:"secret_key"`
-	RawRegion      string `mapstructure:"region"`
-	SkipValidation bool   `mapstructure:"skip_region_validation"`
-	Token          string `mapstructure:"token"`
-	ProfileName    string `mapstructure:"profile"`
+	AccessKey         string `mapstructure:"access_key"`
+	SecretKey         string `mapstructure:"secret_key"`
+	RawRegion         string `mapstructure:"region"`
+	SkipValidation    bool   `mapstructure:"skip_region_validation"`
+	Token             string `mapstructure:"token"`
+	ProfileName       string `mapstructure:"profile"`
+	CustomEndpointEc2 string `mapstructure:"custom_endpoint_ec2"`
 }
 
 // Config returns a valid aws.Config object for access to AWS services, or
@@ -35,6 +36,11 @@ func (c *AccessConfig) Config() (*aws.Config, error) {
 		return nil, err
 	}
 	config := aws.NewConfig().WithRegion(region).WithMaxRetries(11)
+
+	if c.CustomEndpointEc2 != "" {
+		config.Endpoint = &c.CustomEndpointEc2
+	}
+
 	if c.ProfileName != "" {
 		profile, err := NewFromProfile(c.ProfileName)
 		if err != nil {

builder/amazon/common/step_security_group.go

@@ -55,8 +55,12 @@ func (s *StepSecurityGroup) Run(state multistep.StateBag) multistep.StepAction {
 	group := &ec2.CreateSecurityGroupInput{
 		GroupName:   &groupName,
 		Description: aws.String("Temporary group for Packer"),
-		VpcId:       &s.VpcId,
 	}
+
+	if s.VpcId != "" {
+		group.VpcId = &s.VpcId
+	}
+
 	groupResp, err := ec2conn.CreateSecurityGroup(group)
 	if err != nil {
 		ui.Error(err.Error())