Elastalert: blist no longer works in Python 3.9

[maybe-sybr]

ref: DanielStutzbach/blist#90

blist is used for its sortedlist in ruletypes.py and appears to be abandonware - might I suggest that the SortedKeyList [0] from python-sortedcontainers [1] could replace it?

[0] http://www.grantjenks.com/docs/sortedcontainers/introduction.html#sorted-key-list
[1] https://github.com/grantjenks/python-sortedcontainers

[nsano-rururu]

It seems that the operation is guaranteed up to 3.6. Therefore, it seems that the operation of 3.9 is not guaranteed.

[nsano-rururu]

It's just a personal impression, but I think it's better to change to another library than to continue using blist.
Are you planning to make a pull request to change blist to python-sorted containers?

File to change
requirements.txt
setup.py
elastalert/ruletypes.py

[nsano-rururu]

ElastAlert shouldn't officially support Python 3.8 as it starts with Syntax Warning from Python 3.8.

SyntaxWarning: "is" with a literal. Did you mean "=="?

_Files that may need to be modified_

elastalert/
　__init__.py
　alerts.py
　create_index.py
　elastalert.py
　kibana_discover.py
　loaders.py
　opsgenie.py
　ruletypes.py
　test_rule.py
　util.py
tests/
　base_test.py
　elasticsearch_test.py
　kibana_discover_test.py
　loaders_test.py
　rules_test.py
　util_test.py

SyntaxWarning: "is not" with a literal. Did you mean "!="?

_Files that may need to be modified_

elastalert/
　alerts.py
　config.py
　create_index.py
　elastalert.py
　opsgenie.py
　ruletypes.py
　util.py

[nsano-rururu]

If you want to upgrade Python version, you may need to update the following files used by Travis CI
Need to add tests in Python 3.7 / 3.8 / 3.9 environment?

Dockerfile-test
travis.yml

[maybe-sybr]

@nsano-rururu - I can make a PR when i get some time for the replacement of blist. It won't be today but perhaps over the weekend.

wrt those syntaxwarnings, I had a quick grep though the source myself and it appears that most of those are checks against None, which seems like a bad warning rather than an actual syntax/logical issue. What did you use to get those warnings out? I can't replicate them with -Wdefault in a simple test file.

$ python -Wd <<EOF
foo = None
if foo is None:
  pass
if foo is not None:
  pass
if foo:
  pass
if not foo:
  pass
if foo == None:
  pass
if foo != None:
  pass
EOF
$ python -Wd <<EOF
foo = tuple()
if foo is ():
  pass
if foo is not ():
  pass
if foo:
  pass
if not foo:
  pass
if foo == ():
  pass
if foo != ():
  pass
EOF
<stdin>:2: SyntaxWarning: "is" with a literal. Did you mean "=="?
<stdin>:4: SyntaxWarning: "is not" with a literal. Did you mean "!="?

Those warnings for a literal tuple look right to me, and as I would expect using is against None is fine.

[nsano-rururu]

Then what about the situation?

[maybe-sybr]

I've not had the time to put up changes for this unfortunately. For the moment I've worked around the issue by pinning my container images to build from a python:3.8 base image. I've got a few higher priority things to get out of the way before I dig into this - happy for someone else to put up a PR in the meantime if it's affecting them as well.

[PhracturedBlue]

I also had issues with blist with python 3.7. sortedcontainers worked well for me as per https://github.com/Yelp/elastalert/issues/2693

[nsano-rururu]

elastalert/ruletypes.py

from blist import sortedlist
　↓
from sortedcontainers import SortedKeyList as sortedlist

requirements.txt

blist>=1.3.6
　↓
sortedcontainers>=2.2.2

setup.py

'blist>=1.3.6'
　↓
'sortedcontainers>=2.2.2'