Broken latest build on Python 3.9 / Blist 1.3.6 ? (_PyObject_GC_IS_TRACKED symbol missing)

[cbrwflo]

First of all, thank you for stepping up and helping fill the void the Yelp mantainers have left behind! It's awesome to have community support for ElastAlert.

I noticed the latest tagged Docker image (9206ee1e) fails to start with the known issue in Py 3.9 with Blist causing missing symbol: _PyObject_GC_IS_TRACKED.

This was fixed by rolling back to 0.2.4 (ce82cce4)

# after cloning, grabbed an example elastalert.yaml
curl https://raw.githubusercontent.com/Yelp/elastalert/master/config.yaml.example > ./elastalert.yaml
docker run --rm -d -v $(pwd)/elastalert.yaml:/opt/config/elastalert_config.yaml jertel/elastalert-docker


# Elastic Version: 7.1.1
# Reading Elastic 6 index mappings:
# Reading index mapping 'es_mappings/6/silence.json'
# Reading index mapping 'es_mappings/6/elastalert_status.json'
# Reading index mapping 'es_mappings/6/elastalert.json'
# Reading index mapping 'es_mappings/6/past_elastalert.json'
# Reading index mapping 'es_mappings/6/elastalert_error.json'
# Index elastalert_status already exists. Skipping index creation.
# Traceback (most recent call last):
#   File "/usr/local/bin/elastalert", line 5, in <module>
#     from elastalert.elastalert import main
#   File "/usr/local/lib/python3.9/site-packages/elastalert/elastalert.py", line 31, in <module>
#     from .config import load_conf
#   File "/usr/local/lib/python3.9/site-packages/elastalert/config.py", line 9, in <module>
#     from . import loaders
#   File "/usr/local/lib/python3.9/site-packages/elastalert/loaders.py", line 16, in <module>
#     from . import ruletypes
#   File "/usr/local/lib/python3.9/site-packages/elastalert/ruletypes.py", line 6, in <module>
#     from blist import sortedlist
#   File "/usr/local/lib/python3.9/site-packages/blist/__init__.py", line 2, in <module>
#     from blist._blist import *
# ImportError: Error relocating /usr/local/lib/python3.9/site-packages/blist/_blist.cpython-39-x86_64-linux-gnu.so: _PyObject_GC_IS_TRACKED: symbol not found

[jertel]

Thanks for the detailed problem report. I've pinned the jertel/elastalert-docker:latest image to Python 3.6 to avoid this blist lib conflict. If you'd prefer to continue using Python 3.9 you can use the jertel/elastalert-docker:latest-alt image, which is based on my fork of elastalert (https://github.com/jertel/elastalert) and includes PRs like this (Yelp/elastalert#2983), that the Yelp team has not merged.