Fix a bug where an unbounded number of credentials wrappers got added. (

#296)

* Fix a bug where an unbounded number of credentials wrappers got added.

This fixes #1251, where the fact that we were sharing a single
`httplib2.Http` instance caused each request to add an additional
credentials wrapper around that single instance.

That, in turn, caused a `RuntimeError: maximum recursion depth ...`
error message once too many API calls had been made.

* Only copy the http instance when we need to

* Include the fix for authorizing HTTP requests in the older `datalab` module

datalab/utils/_http.py

@@ -19,6 +19,7 @@
 from past.builtins import basestring
 from builtins import object
 
+import copy
 import datetime
 import json
 import urllib.request, urllib.parse, urllib.error
@@ -119,9 +120,12 @@ def request(url, args=None, data=None, headers=None, method=None,
     if method is None:
       method = 'GET'
 
-    # Authorize with credentials if given.
     http = Http.http
+
+    # Authorize with credentials if given.
     if credentials is not None:
+      # Make a copy of the shared http instance before we modify it.
+      http = copy.copy(http)
       http = credentials.authorize(http)
     if stats is not None:
       stats['duration'] = datetime.datetime.utcnow()

google/datalab/utils/_http.py

@@ -19,6 +19,7 @@
 from past.builtins import basestring
 from builtins import object
 
+import copy
 import datetime
 import json
 import urllib.request, urllib.parse, urllib.error
@@ -119,9 +120,12 @@ def request(url, args=None, data=None, headers=None, method=None,
     if method is None:
       method = 'GET'
 
-    # Authorize with credentials if given
     http = Http.http
+
+    # Authorize with credentials if given
     if credentials is not None:
+      # Make a copy of the shared http instance before we modify it.
+      http = copy.copy(http)
       http = credentials.authorize(http)
     if stats is not None:
       stats['duration'] = datetime.datetime.utcnow()