Adds region defaults

Signed-off-by: Simon Thulbourn <simon+github@thulbourn.com>

drivers/amazonec2/amazonec2.go

@@ -21,7 +21,6 @@ import (
 const (
 	driverName               = "amazonec2"
 	defaultRegion            = "us-east-1"
-	defaultAMI               = "ami-4ae27e22"
 	defaultInstanceType      = "t2.micro"
 	defaultRootSize          = 16
 	ipRange                  = "0.0.0.0/0"
@@ -96,7 +95,6 @@ func GetCreateFlags() []cli.Flag {
 		cli.StringFlag{
 			Name:   "amazonec2-ami",
 			Usage:  "AWS machine image",
-			Value:  defaultAMI,
 			EnvVar: "AWS_AMI",
 		},
 		cli.StringFlag{
@@ -150,11 +148,21 @@ func NewDriver(machineName string, storePath string, caCert string, privateKey s
 }
 
 func (d *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
+	region, err := validateAwsRegion(flags.String("amazonec2-region"))
+	if err != nil {
+		return nil
+	}
+
+	image := flags.String("amazonec2-ami")
+	if len(image) == 0 {
+		image = regionDetails[region].AmiId
+	}
+
 	d.AccessKey = flags.String("amazonec2-access-key")
 	d.SecretKey = flags.String("amazonec2-secret-key")
 	d.SessionToken = flags.String("amazonec2-session-token")
-	d.AMI = flags.String("amazonec2-ami")
-	d.Region = flags.String("amazonec2-region")
+	d.Region = region
+	d.AMI = image
 	d.InstanceType = flags.String("amazonec2-instance-type")
 	d.VpcId = flags.String("amazonec2-vpc-id")
 	d.SubnetId = flags.String("amazonec2-subnet-id")

drivers/amazonec2/amazonec2_test.go

@@ -92,3 +92,36 @@ func TestConfigureSecurityGroupPermissionsDockerAndSsh(t *testing.T) {
 		t.Fatalf("expected 0 permissions; received %d", len(perms))
 	}
 }
+
+func TestAwsRegionList(t *testing.T) {
+}
+
+func TestValidateAwsRegionValid(t *testing.T) {
+	regions := []string{"eu-west-1", "eu-central-1"}
+
+	for _, v := range regions {
+		r, err := validateAwsRegion(v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if v != r {
+			t.Fatal("Wrong region returned")
+		}
+	}
+}
+
+func TestValidateAwsRegionInvalid(t *testing.T) {
+	regions := []string{"eu-west-2", "eu-central-2"}
+
+	for _, v := range regions {
+		r, err := validateAwsRegion(v)
+		if err == nil {
+			t.Fatal("No error returned")
+		}
+
+		if v == r {
+			t.Fatal("Wrong region returned")
+		}
+	}
+}

drivers/amazonec2/utils.go

@@ -0,0 +1,51 @@
+package amazonec2
+
+import (
+	"errors"
+)
+
+var (
+	errInvalidRegion  = errors.New("invalid region specified")
+	errNoVpcs         = errors.New("No VPCs found in region")
+	errMachineFailure = errors.New("Machine failed to start")
+	errNoIP           = errors.New("No IP Address associated with the instance")
+	errComplete       = errors.New("Complete")
+)
+
+type region struct {
+	AmiId string
+}
+
+var regionDetails map[string]*region = map[string]*region{
+	"ap-northeast-1": {"ami-44f1e245"},
+	"ap-southeast-1": {"ami-f95875ab"},
+	"ap-southeast-2": {"ami-890b62b3"},
+	"cn-north-1":     {"ami-fe7ae8c7"},
+	"eu-west-1":      {"ami-823686f5"},
+	"eu-central-1":   {"ami-ac1524b1"},
+	"sa-east-1":      {"ami-c770c1da"},
+	"us-east-1":      {"ami-4ae27e22"},
+	"us-west-1":      {"ami-d1180894"},
+	"us-west-2":      {"ami-898dd9b9"},
+	"us-gov-west-1":  {"ami-cf5630ec"},
+}
+
+func awsRegionsList() []string {
+	var list []string
+
+	for k := range regionDetails {
+		list = append(list, k)
+	}
+
+	return list
+}
+
+func validateAwsRegion(region string) (string, error) {
+	for _, v := range awsRegionsList() {
+		if v == region {
+			return region, nil
+		}
+	}
+
+	return "", errInvalidRegion
+}