tfdbg: add Session.sess_str check to Session wrapper base class

Change: 144464664

tensorflow/python/debug/wrappers/framework.py

@@ -325,10 +325,17 @@ class BaseDebugWrapperSession(session.SessionInterface):
 
     Raises:
       ValueError: On invalid `OnSessionInitAction` value.
+      NotImplementedError: If a non-DirectSession sess object is received.
     """
 
     _check_type(sess, session.BaseSession)
 
+    # TODO(cais): Remove this check once tfdbg is integrated with GrpcSession.
+    if sess.sess_str:
+      raise NotImplementedError(
+          "Non-DirectSession support is not available from TensorFlow "
+          "Debugger yet (sess_str=%s)" % sess.sess_str)
+
     # The session being wrapped.
     self._sess = sess
 

tensorflow/python/debug/wrappers/framework_test.py

@@ -311,6 +311,18 @@ class DebugWrapperSessionTest(test_util.TensorFlowTestCase):
                                       self._observer)
     wrapper.close()
 
+  def testUsingNonDirectSessionRaisesNotImplementedError(self):
+    # TODO(cais): Remove this test once tfdbg is integrated with GrpcSession.
+    fake_non_direct_session = session.Session()
+    fake_non_direct_session._target = "foo"
+
+    with self.assertRaisesRegexp(
+        NotImplementedError,
+        r"Non-DirectSession support is not available from TensorFlow Debugger "
+        r"yet \(sess_str=foo\)"):
+      TestDebugWrapperSession(
+          fake_non_direct_session, self._dump_root, self._observer)
+
 
 if __name__ == "__main__":
   googletest.main()