DEP8 failure in mantic with new memcached

[Andreas Hasenack]

Lots of tests are failing:
https://autopkgtest.ubuntu.com/results/autopkgtest-mantic/mantic/amd64/c/cachelib/20230518_094534_ac160@/log.gz

============================= test session starts ==============================
platform linux -- Python 3.11.3, pytest-7.2.1, pluggy-1.0.0+repack
rootdir: /tmp/autopkgtest.rB0PMy/autopkgtest_tmp
plugins: xprocess-0.22.2
collected 120 items / 1 skipped

tests/test_base_cache.py ............ [ 10%]
tests/test_file_system_cache.py ........................................ [ 43%]
........ [ 50%]
tests/test_interface_uniformity.py E [ 50%]
tests/test_memcached_cache.py EEEEEEEEEEE [ 60%]
tests/test_redis_cache.py ...................... [ 78%]
tests/test_simple_cache.py .......................... [100%]

==================================== ERRORS ====================================

Last time they passed in mantic was with memcached 1.6.16 it seems.

This needs further investigation.

[Andreas Hasenack (ahasenack)]

https://github.com/pallets-eco/cachelib/issues/39

upstream report, unfortunately closed too early I think

[Andreas Hasenack (ahasenack)]

The error seems to be "address already in use" when the test that exercises memcached starts:
$ cat /tmp/autopkgtest.UbrNG3/autopkgtest_tmp/.pytest_cache/d/.xprocess/pylibmc/xprocess.log
@@__xproc_block_delimiter__@@
slab class 1: chunk size 96 perslab 10922
(...)
failed to listen on TCP port 11211: Address already in use

There is a memcached running on 127.0.0.1:11211 already, that's the one started by systemd, but that is the case with memcached 1.6.18 too. I haven't figured out yet what changed with 1.6.19 in that regard.

Ah, maybe...

With 1.6.19, memcached is listening on BOTH of these:
tcp LISTEN 0 1024 127.0.0.1:11211 0.0.0.0:* users:(("memcached",pid=2559,fd=22))

tcp LISTEN 0 1024 [::1]:11211 [::]:* users:(("memcached",pid=2559,fd=23))

Whereas with 1.6.18 it's just:
tcp LISTEN 0 1024 127.0.0.1:11211 0.0.0.0:* users:(("memcached",pid=2431,fd=22))

Which allows the memcached from the test suite to start and take the ipv6 slot. Just a theory, let's see...

[Andreas Hasenack (ahasenack)]

Yeah, 1.6.18 is being started with

/usr/bin/memcached -m 64 -p 11211 -u memcache -l 127.0.0.1 -P /var/run/memcached/memcached.pid

And 1.6.19 is being started with:

/usr/bin/memcached -m 64 -p 11211 -u memcache -l 127.0.0.1 -l ::1 -P /var/run/memcached/memcached.pid

A simple fix for the DEP8 test would be to stop the system-installed memcached before running the test. But I'll check what else can be done that would not require this test to run as root just because of that.

[Andreas Hasenack (ahasenack)]

Sent fix to debian via https://salsa.debian.org/python-team/packages/cachelib/-/merge_requests/2

[Launchpad Janitor (janitor)]

This bug was fixed in the package cachelib - 0.9.0-1ubuntu1

---------------
cachelib (0.9.0-1ubuntu1) mantic; urgency=medium

  * Stop system memcached before running the test, to avoid a port
    conflict (LP: #2021994):
    - d/t/control: add needs-root restriction
    - d/t/upstream: stop the system memcached, and run the test as an
      unprivileged user as before

 -- Andreas Hasenack <email address hidden> Wed, 14 Jun 2023 15:06:55 -0300