Fix our provider validation to allow file paths.

google/provider.go

@@ -3,6 +3,7 @@ package google
 import (
 	"encoding/json"
 	"fmt"
+	"os"
 
 	"github.com/hashicorp/terraform/helper/mutexkv"
 	"github.com/hashicorp/terraform/helper/schema"
@@ -198,6 +199,10 @@ func validateCredentials(v interface{}, k string) (warnings []string, errors []e
 		return
 	}
 	creds := v.(string)
+	// if this is a path and we can stat it, assume it's ok
+	if _, err := os.Stat(creds); err == nil {
+		return
+	}
 	var account accountFile
 	if err := json.Unmarshal([]byte(creds), &account); err != nil {
 		errors = append(errors,

google/provider_test.go

@@ -88,6 +88,30 @@ func TestProvider_getRegionFromZone(t *testing.T) {
 	}
 }
 
+func TestProvider_loadCredentialsFromFile(t *testing.T) {
+	ws, es := validateCredentials(testFakeCredentialsPath, "")
+	if len(ws) != 0 {
+		t.Errorf("Expected %d warnings, got %v", len(ws), ws)
+	}
+	if len(es) != 0 {
+		t.Errorf("Expected %d errors, got %v", len(es), es)
+	}
+}
+
+func TestProvider_loadCredentialsFromJSON(t *testing.T) {
+	contents, err := ioutil.ReadFile(testFakeCredentialsPath)
+	if err != nil {
+		t.Fatalf("Unexpected error: %s", err)
+	}
+	ws, es := validateCredentials(string(contents), "")
+	if len(ws) != 0 {
+		t.Errorf("Expected %d warnings, got %v", len(ws), ws)
+	}
+	if len(es) != 0 {
+		t.Errorf("Expected %d errors, got %v", len(es), es)
+	}
+}
+
 // getTestRegion has the same logic as the provider's getRegion, to be used in tests.
 func getTestRegion(is *terraform.InstanceState, config *Config) (string, error) {
 	if res, ok := is.Attributes["region"]; ok {