swift-init fails with TypeError: reduce() of empty sequence with no initial value

[Kirill Zaitsev]

While running latest devstack I've encountered the following error:

2017-07-31 08:19:47.008 | +lib/swift:start_swift:831 [[ True == \T\r\u\e ]]
2017-07-31 08:19:47.024 | +lib/swift:start_swift:832 swift-init --run-dir=/opt/stack/data/swift/run rest start
2017-07-31 08:19:59.122 | Starting container-updater...(/etc/swift/container-server/1.conf)
2017-07-31 08:19:59.122 | Starting account-auditor...(/etc/swift/account-server/1.conf)
2017-07-31 08:19:59.122 | Starting object-replicator...(/etc/swift/object-server/1.conf)
2017-07-31 08:19:59.122 | Starting container-replicator...(/etc/swift/container-server/1.conf)
2017-07-31 08:19:59.122 | Starting object-auditor...(/etc/swift/object-server/1.conf)
2017-07-31 08:19:59.123 | Unable to locate config for object-expirer
2017-07-31 08:19:59.123 | Starting container-auditor...(/etc/swift/container-server/1.conf)
2017-07-31 08:19:59.123 | Starting account-replicator...(/etc/swift/account-server/1.conf)
2017-07-31 08:19:59.123 | Starting account-reaper...(/etc/swift/account-server/1.conf)
2017-07-31 08:19:59.123 | Starting container-sync...(/etc/swift/container-server/1.conf)
2017-07-31 08:19:59.123 | Starting object-updater...(/etc/swift/object-server/1.conf)
2017-07-31 08:19:59.123 | Unable to locate config for container-reconciler
2017-07-31 08:19:59.123 | Starting object-reconstructor...(/etc/swift/object-server/1.conf)
2017-07-31 08:19:59.123 | Traceback (most recent call last):
2017-07-31 08:19:59.123 | File "/usr/local/bin/swift-object-reconstructor", line 6, in <module>
2017-07-31 08:19:59.123 | exec(compile(open(__file__).read(), __file__, 'exec'))
2017-07-31 08:19:59.123 | File "/opt/stack/swift/bin/swift-object-reconstructor", line 31, in <module>
2017-07-31 08:19:59.124 | run_daemon(ObjectReconstructor, conf_file, **options)
2017-07-31 08:19:59.124 | File "/opt/stack/swift/swift/common/daemon.py", line 301, in run_daemon
2017-07-31 08:19:59.124 | DaemonStrategy(klass(conf), logger).run(once=once, **kwargs)
2017-07-31 08:19:59.124 | File "/opt/stack/swift/swift/obj/reconstructor.py", line 228, in __init__
2017-07-31 08:19:59.124 | self.all_local_devices = self.get_local_devices()
2017-07-31 08:19:59.124 | File "/opt/stack/swift/swift/obj/reconstructor.py", line 1037, in get_local_devices
2017-07-31 08:19:59.124 | for devices in policy2devices.values()))
2017-07-31 08:19:59.124 | TypeError: reduce() of empty sequence with no initial value

[Alistair Coles (alistair-coles)]

Bug introduced here https://review.openstack.org/478416

Fix proposed here https://review.openstack.org/#/c/489133/1 and here https://review.openstack.org/#/c/489112/

The TypeError will be raised when the object-reconstructor is run and no EC policies are configured. When there are no EC policies, the object-reconstructor has no work to do, so no data is 'at risk'. Nevertheless the TypeError should be fixed.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Kirill Zaitsev (<email address hidden>) on branch: master
Review: https://review.openstack.org/489133
Reason: in favor of https://review.openstack.org/#/c/489112/1

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/489112
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=45cc1d02d06f33530cefe742465828f5d0d5cd12
Submitter: Jenkins
Branch: master

commit 45cc1d02d06f33530cefe742465828f5d0d5cd12
Author: Kota Tsuyuzaki <email address hidden>
Date: Mon Jul 31 16:20:11 2017 +0900

    Fix reconstructer to be able to run non ec policy environment

    Since the related change, object-reconstructor gathers the local devices
    for ec policy via get_local_devices method but the method causes TypeError when
    attempting *reduce* for empty set list. the list can be empty when no EC config
    found in swift.conf.

    This patch fixes the get_local_devices to return empty set even when no ec config
    in swift.conf without errors.

    Co-Authored-By: Kirill Zaitsev <email address hidden>
    Change-Id: Ic121fb547966787a43f9eae83c91bb2bf640c4be
    Related-Change: 701a172afac37229b85ea762f20428f6f422d29b
    Closes-Bug: #1707595

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/489281
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=8d05325f03a6ca91cf886c0680455c962243ffb9
Submitter: Jenkins
Branch: master

commit 8d05325f03a6ca91cf886c0680455c962243ffb9
Author: Tim Burke <email address hidden>
Date: Mon Jul 31 17:24:40 2017 +0000

    Test reconstruct() with no EC policies

    We have a test for get_local_devices, but let's make some broader
    assertions as well.

    Related-Bug: #1707595
    Change-Id: Ifa696207ffdb3b39650dfeaa3e7c6cfda94050db

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/swift 2.15.1 release.