builder/googlecompute: validate image_family

builder/googlecompute/config.go

@@ -3,6 +3,7 @@ package googlecompute
 import (
 	"errors"
 	"fmt"
+	"regexp"
 	"time"
 
 	"github.com/mitchellh/packer/common"
@@ -94,6 +95,19 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		}
 	}
 
+	if len(c.ImageFamily) > 63 {
+		errs = packer.MultiErrorAppend(errs,
+			errors.New("Invalid image family: Must not be longer than 63 characters"))
+	}
+
+	if c.ImageFamily != "" {
+		if !regexp.MustCompile(`^[a-z]([-a-z0-9]{0,61}[a-z0-9])?$`).MatchString(c.ImageFamily) {
+			errs = packer.MultiErrorAppend(errs,
+				errors.New("Invalid image family: The first character must be a lowercase letter, and all following characters must be a dash, lowercase letter, or digit, except the last character, which cannot be a dash"))
+		}
+
+	}
+
 	if c.InstanceName == "" {
 		c.InstanceName = fmt.Sprintf("packer-%s", uuid.TimeOrderedUUID())
 	}

builder/googlecompute/config_test.go

@@ -123,6 +123,11 @@ func TestConfigPrepare(t *testing.T) {
 			"foo-bar",
 			false,
 		},
+		{
+			"image_family",
+			"foo bar",
+			true,
+		},
 	}
 
 	for _, tc := range cases {