Attribute error during timeout cancelling transfer

- Change remaining instances of errors.TicketCancelTimeout to errors.TransferCancelTimeout
- Include an initial unit test that attempts to mimic two connection attempts:
  - Connection 1 initiates the transfer
  - Connection 2 issues the delete request
- Fixed unit test to incorporate suggestions:
  - Use testutil.create_tempfile to create temporary file
  - Use a smaller file, 8 MiB (hopefully) is enough to simulate the issue
  - Use monkeypatch.setattr() to modify global values for test_delete_conflict test
  - Use time.sleep() instead of reading one byte

Signed-off-by: jsattelb <jsattelb@ldeo.columbia.edu>

ovirt_imageio/_internal/auth.py

@@ -291,8 +291,8 @@ def cancel(self, timeout=60):
             True if ticket can be removed.
 
         Raises:
-            errors.TicketCancelTimeout if timeout is non-zero and the ticket is
-            still used when the timeout expires.
+            errors.TransferCancelTimeout if timeout is non-zero and the ticket
+            is still used when the timeout expires.
         """
         log.debug("Cancelling transfer %s", self.transfer_id)
 

ovirt_imageio/_internal/handlers/tickets.py

@@ -97,7 +97,7 @@ def delete(self, req, resp, ticket_id):
                          req.client_addr, ticket.transfer_id)
                 try:
                     self.auth.remove(ticket_id)
-                except errors.TicketCancelTimeout as e:
+                except errors.TransferCancelTimeout as e:
                     # The ticket is still used by some connection so we cannot
                     # remove it. The caller can retry the call again when the
                     # number connections reach zero.

test/handlers/tickets_test.py

@@ -3,6 +3,7 @@
 
 import http.client as http_client
 import json
+import time
 import uuid
 
 import pytest
@@ -397,3 +398,24 @@ def test_delete_all(srv):
         # Note: incorrect according to RFC, but required for vdsm.
         assert res.getheader("content-length") == "0"
         pytest.raises(KeyError, srv.auth.get, ticket["uuid"])
+
+
+def test_delete_conflict(srv, tmpdir, monkeypatch):
+    image = testutil.create_tempfile(tmpdir, "image", size=8 * 1024**2)
+    ticket = testutil.create_ticket(url="file://" + str(image))
+    srv.auth.add(ticket)
+
+    # Use very short timeout to make the test fast.
+    monkeypatch.setattr(srv.config.control, "remove_timeout", 0.001)
+
+    with http.RemoteClient(srv.config) as remote_client:
+        remote_client.get("/images/" + ticket["uuid"])
+
+        # Wait enough time to get the server connnection thread block on the
+        # client socket trying to write more data.
+        time.sleep(0.1)
+
+        with http.ControlClient(srv.config) as control_client:
+            res = control_client.delete("/tickets/" + ticket["uuid"])
+            res.read()
+            assert res.status == 409