commit 6e86c939aa8ef3b801b69f7dc6dc940e38d5f85c
author weitaiting <weitaiting@users.noreply.github.com> Sat Aug 12 03:26:59 2017 +0800
committer Jon Wayne Parrott <jonwayne@google.com> Fri Aug 11 12:26:59 2017 -0700
tree 29944e806445b44cb6430a72561681f0264f1fa9
parent 6a3f0ec79bf4ea115190d7006ca71a61f3d5f2df

Add error message to handle case of empty string or missing file for GOOGLE_APPLICATION_CREDENTIALS (#188)

Fixes #161 

google/auth/_default.py

diff --git a/google/auth/_default.py b/google/auth/_default.py
index 1e91368..7dac642 100644
--- a/google/auth/_default.py
+++ b/google/auth/_default.py
@@ -58,8 +58,12 @@
 
     Raises:
         google.auth.exceptions.DefaultCredentialsError: if the file is in the
-            wrong format.
+            wrong format or is missing.
     """
+    if not os.path.exists(filename):
+        raise exceptions.DefaultCredentialsError(
+            'File {} was not found.'.format(filename))
+
     with io.open(filename, 'r') as file_obj:
         try:
             info = json.load(file_obj)