Newer version of itsdangerous incompatible with Flask:1.1.2

[AnthonyGigerich]

With the 2.1.0 version of itsdangerous on Feb 18, 2022, it is now only compatible with Flask>=1.1.4
label-studio-ml is fixing the version of Flask to 1.1.2

Error when starting the simple text classifier example:

server    | [2022-02-28 08:49:14 +0000] [1] [INFO] Starting gunicorn 20.1.0
server    | [2022-02-28 08:49:14 +0000] [1] [INFO] Listening at: http://0.0.0.0:9090 (1)
server    | [2022-02-28 08:49:14 +0000] [1] [INFO] Using worker: gthread
server    | [2022-02-28 08:49:14 +0000] [8] [INFO] Booting worker with pid: 8
server    | [2022-02-28 08:49:14 +0000] [1] [INFO] Shutting down: Master
server    | [2022-02-28 08:49:14 +0000] [1] [INFO] Reason: Worker failed to boot.
server exited with code 3

If using --preload on the gunicorn call of the Dockerfile to have better logs:

ImportError: cannot import name 'json' from 'itsdangerous' (/usr/local/lib/python3.8/site-packages/itsdangerous/__init__.py)

Temporary fix for me was to downgrade the version of itsdangerous to 2.0.1 in the requirements of the text classifier example backend

Best solution might be to upgrade Flask to 1.1.4 for label-studio-ml dependencies

Related issue and proposed solution on Microsoft Azure CLI:
Azure/azure-cli#21363 (comment)

[ajaymaity]

This pointed me in the right direction. I had to also fix the version of jinja2 and werkzeug. I added the following in requirements.txt file:

itsdangerous==2.0.1
jinja2==3.0.3
werkzeug==2.0.2

[makseq]

The fix was merged yesterday:
https://github.com/heartexlabs/label-studio-ml-backend/pull/96/files