providers/google: update schema to use a DefaultFunc

This makes testing easier and gives you a way to configure the provider
using env variables. It also makes the provider more inline following
the TF 0.2 approach.

builtin/providers/google/config.go

@@ -29,20 +29,6 @@ func (c *Config) loadAndValidate() error {
 	var account accountFile
 	var secrets clientSecretsFile
 
-	// TODO: validation that it isn't blank
-	if c.AccountFile == "" {
-		c.AccountFile = os.Getenv("GOOGLE_ACCOUNT_FILE")
-	}
-	if c.ClientSecretsFile == "" {
-		c.ClientSecretsFile = os.Getenv("GOOGLE_CLIENT_FILE")
-	}
-	if c.Project == "" {
-		c.Project = os.Getenv("GOOGLE_PROJECT")
-	}
-	if c.Region == "" {
-		c.Region = os.Getenv("GOOGLE_REGION")
-	}
-
 	if err := loadJSON(&account, c.AccountFile); err != nil {
 		return fmt.Errorf(
 			"Error loading account file '%s': %s",

builtin/providers/google/provider.go

@@ -1,6 +1,8 @@
 package google
 
 import (
+	"os"
+
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -12,21 +14,25 @@ func Provider() terraform.ResourceProvider {
 			"account_file": &schema.Schema{
 				Type:        schema.TypeString,
 				Required:    true,
+				DefaultFunc: envDefaultFunc("GOOGLE_ACCOUNT_FILE"),
 			},
 
 			"client_secrets_file": &schema.Schema{
 				Type:        schema.TypeString,
 				Required:    true,
+				DefaultFunc: envDefaultFunc("GOOGLE_CLIENT_FILE"),
 			},
 
 			"project": &schema.Schema{
 				Type:        schema.TypeString,
 				Required:    true,
+				DefaultFunc: envDefaultFunc("GOOGLE_PROJECT"),
 			},
 
 			"region": &schema.Schema{
 				Type:        schema.TypeString,
 				Required:    true,
+				DefaultFunc: envDefaultFunc("GOOGLE_REGION"),
 			},
 		},
 
@@ -43,6 +49,16 @@ func Provider() terraform.ResourceProvider {
 	}
 }
 
+func envDefaultFunc(k string) schema.SchemaDefaultFunc {
+	return func() (interface{}, error) {
+		if v := os.Getenv(k); v != "" {
+			return v, nil
+		}
+
+		return nil, nil
+	}
+}
+
 func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 	config := Config{
 		AccountFile:       d.Get("account_file").(string),

builtin/providers/google/provider_test.go

@@ -40,4 +40,8 @@ func testAccPreCheck(t *testing.T) {
 	if v := os.Getenv("GOOGLE_PROJECT"); v == "" {
 		t.Fatal("GOOGLE_PROJECT must be set for acceptance tests")
 	}
+
+	if v := os.Getenv("GOOGLE_REGION"); v != "us-central1" {
+		t.Fatal("GOOGLE_REGION must be set to us-central1 for acceptance tests")
+	}
 }