[Bug 1889396] Re: ML2 plugin fails with "AttributeError: module 'select' has no attribute 'poll'"

Corey Bryant 1889396 at bugs.launchpad.net
Tue Sep 1 13:36:22 UTC 2020 

** Also affects: Ubuntu Groovy
   Importance: Undecided
       Status: New

** No longer affects: ubuntu

** No longer affects: Ubuntu Groovy

** Also affects: networking-arista (Ubuntu)
   Importance: Undecided
       Status: New

** Also affects: networking-arista (Ubuntu Groovy)
   Importance: Undecided
       Status: New

** Changed in: networking-arista (Ubuntu Groovy)
   Importance: Undecided => High

** Changed in: networking-arista (Ubuntu Groovy)
       Status: New => Triaged

** Also affects: networking-arista (Ubuntu Focal)
   Importance: Undecided
       Status: New

** Changed in: networking-arista (Ubuntu Focal)
   Importance: Undecided => High

** Changed in: networking-arista (Ubuntu Focal)
       Status: New => Triaged

** Also affects: cloud-archive/ussuri
   Importance: Undecided
       Status: New

** Changed in: cloud-archive/ussuri
   Importance: Undecided => High

** Changed in: cloud-archive/ussuri
       Status: New => Triaged

** Also affects: cloud-archive/train
   Importance: Undecided
       Status: New

** Changed in: cloud-archive/train
   Importance: Undecided => High

** Changed in: cloud-archive/train
       Status: New => Triaged

** Also affects: cloud-archive/stein
   Importance: Undecided
       Status: New

** Changed in: cloud-archive/stein
   Importance: Undecided => High

** Changed in: cloud-archive/stein
       Status: New => Triaged

** Changed in: cloud-archive
   Importance: Undecided => High

** Changed in: cloud-archive
       Status: New => Triaged

** Summary changed:

- ML2 plugin fails with "AttributeError: module 'select' has no attribute 'poll'"
+ [SRU] ML2 plugin fails with "AttributeError: module 'select' has no attribute 'poll'"

** Description changed:

- When running the latest Neutron ML2 Arista plugin on Ubuntu 18.04 with
- Python 3.6 I get:
+ [Impact]
+ When running the latest Neutron ML2 Arista plugin on Ubuntu 18.04 with Python 3.6 I get:
  
  Traceback (most recent call last):
-   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 255, in sync_loop
-     sync_required = self.wait_for_sync_required()
-   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 184, in wait_for_sync_required
-     return self.wait_for_mech_driver_update(timeout)
-   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 165, in wait_for_mech_driver_update
-     resource = self.provision_queue.get(timeout=timeout)
-   File "/usr/lib/python3.6/multiprocessing/queues.py", line 104, in get
-     if not self._poll(timeout):
-   File "/usr/lib/python3.6/multiprocessing/connection.py", line 257, in poll
-     return self._poll(timeout)
-   File "/usr/lib/python3.6/multiprocessing/connection.py", line 414, in _poll
-     r = wait([self], timeout)
-   File "/usr/lib/python3.6/multiprocessing/connection.py", line 903, in wait
-     with _WaitSelector() as selector:
-   File "/usr/lib/python3.6/selectors.py", line 348, in __init__
-     self._poll = select.poll()
+   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 255, in sync_loop
+     sync_required = self.wait_for_sync_required()
+   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 184, in wait_for_sync_required
+     return self.wait_for_mech_driver_update(timeout)
+   File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 165, in wait_for_mech_driver_update
+     resource = self.provision_queue.get(timeout=timeout)
+   File "/usr/lib/python3.6/multiprocessing/queues.py", line 104, in get
+     if not self._poll(timeout):
+   File "/usr/lib/python3.6/multiprocessing/connection.py", line 257, in poll
+     return self._poll(timeout)
+   File "/usr/lib/python3.6/multiprocessing/connection.py", line 414, in _poll
+     r = wait([self], timeout)
+   File "/usr/lib/python3.6/multiprocessing/connection.py", line 903, in wait
+     with _WaitSelector() as selector:
+   File "/usr/lib/python3.6/selectors.py", line 348, in __init__
+     self._poll = select.poll()
  AttributeError: module 'select' has no attribute 'poll'
  
  This is because arista_sync.py imports eventlet, which removes poll()
  from select as it is considered "non-green", see
  https://github.com/eventlet/eventlet/issues/608 . However earlier in
  mechanism_arista.py multiprocessing was imported, which then adjusted
  its implementation based on the fact that hasattr(select, 'poll') was
  True at that time.
  
  The first solution that comes to mind would be to import eventlet way
  earlier in the project, before any import to multiprocessing and
  selectors, see http://eventlet.net/doc/patching.html#monkeypatching-the-
  standard-library . But I couldn't find the perfect place for this.
  
  A cleaner solution (validated locally) is to import eventlet.queue.Queue
  instead of multiprocessing.Queue as we use this queue only to
  synchronise with en eventlet.greenthread. See
  http://eventlet.net/doc/modules/queue.html . So basically:
  
  --- a/networking_arista/ml2/mechanism_arista.py
  +++ b/networking_arista/ml2/mechanism_arista.py
  [...]
  -from multiprocessing import Queue
  +from eventlet.queue import Queue
  
  I'll open a review. Thanks!
  
  PS: I'm hitting this while extending the new OpenStack Neutron API
  Arista Plugin charm ( https://opendev.org/openstack/charm-neutron-api-
  plugin-arista ) in order to support the latest OpenStack releases.
+ 
+ [Test Case]
+ 
+ [Regression Potential]

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https://bugs.launchpad.net/bugs/1889396

Title:
  [SRU] ML2 plugin fails with "AttributeError: module 'select' has no
  attribute 'poll'"

Status in Ubuntu Cloud Archive:
  Triaged
Status in Ubuntu Cloud Archive stein series:
  Triaged
Status in Ubuntu Cloud Archive train series:
  Triaged
Status in Ubuntu Cloud Archive ussuri series:
  Triaged
Status in networking-arista:
  Fix Released
Status in networking-arista package in Ubuntu:
  Triaged
Status in networking-arista source package in Focal:
  Triaged
Status in networking-arista source package in Groovy:
  Triaged

Bug description:
  [Impact]
  When running the latest Neutron ML2 Arista plugin on Ubuntu 18.04 with Python 3.6 I get:

  Traceback (most recent call last):
    File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 255, in sync_loop
      sync_required = self.wait_for_sync_required()
    File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 184, in wait_for_sync_required
      return self.wait_for_mech_driver_update(timeout)
    File "/usr/lib/python3/dist-packages/networking_arista/ml2/arista_sync.py", line 165, in wait_for_mech_driver_update
      resource = self.provision_queue.get(timeout=timeout)
    File "/usr/lib/python3.6/multiprocessing/queues.py", line 104, in get
      if not self._poll(timeout):
    File "/usr/lib/python3.6/multiprocessing/connection.py", line 257, in poll
      return self._poll(timeout)
    File "/usr/lib/python3.6/multiprocessing/connection.py", line 414, in _poll
      r = wait([self], timeout)
    File "/usr/lib/python3.6/multiprocessing/connection.py", line 903, in wait
      with _WaitSelector() as selector:
    File "/usr/lib/python3.6/selectors.py", line 348, in __init__
      self._poll = select.poll()
  AttributeError: module 'select' has no attribute 'poll'

  This is because arista_sync.py imports eventlet, which removes poll()
  from select as it is considered "non-green", see
  https://github.com/eventlet/eventlet/issues/608 . However earlier in
  mechanism_arista.py multiprocessing was imported, which then adjusted
  its implementation based on the fact that hasattr(select, 'poll') was
  True at that time.

  The first solution that comes to mind would be to import eventlet way
  earlier in the project, before any import to multiprocessing and
  selectors, see http://eventlet.net/doc/patching.html#monkeypatching-
  the-standard-library . But I couldn't find the perfect place for this.

  A cleaner solution (validated locally) is to import
  eventlet.queue.Queue instead of multiprocessing.Queue as we use this
  queue only to synchronise with en eventlet.greenthread. See
  http://eventlet.net/doc/modules/queue.html . So basically:

  --- a/networking_arista/ml2/mechanism_arista.py
  +++ b/networking_arista/ml2/mechanism_arista.py
  [...]
  -from multiprocessing import Queue
  +from eventlet.queue import Queue

  I'll open a review. Thanks!

  PS: I'm hitting this while extending the new OpenStack Neutron API
  Arista Plugin charm ( https://opendev.org/openstack/charm-neutron-api-
  plugin-arista ) in order to support the latest OpenStack releases.

  [Test Case]

  [Regression Potential]

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