BUG: kwargs configuration no longer passed to model initialization in WSGI files

[WillieMaddox]

Problem Summary

Configuration parameters specified via --with flag or config.json file are not being passed to model initialization in *_wsgi.py files, breaking customization functionality that previously worked.

Expected Behavior

• kwargs from --with flag should be passed to model constructor
• kwargs from config.json should be passed to model constructor
• Model should initialize with custom parameters as specified in configuration

Current Behavior

• kwargs are loaded and parsed correctly
• kwargs are only used during the --check validation step
• kwargs are not passed to the actual model instance used by the web app
• Model initializes with default parameters only

Steps to Reproduce

1. Run any WSGI example with custom kwargs: python examples/yolo/_wsgi.py --with param=value
2. Observe that the web app uses default model parameters

Code Analysis

In examples/yolo/_wsgi.py (and other WSGI files):

kwargs = get_kwargs_from_config()
if args.kwargs:
    kwargs.update(parse_kwargs())

if args.check:
    model = YOLO(**kwargs)  # ✅ kwargs used here
    
app = init_app(
    model_class=YOLO,           # ❌ kwargs not passed here
    basic_auth_user=args.basic_auth_user,
    basic_auth_pass=args.basic_auth_pass,
)

Root Cause

The init_app() function appears to have removed support for passing **kwargs to the model constructor, but the argument parsing logic was left intact, creating a misleading interface.

Questions

1. Is this an intentional breaking change? Should kwargs support be removed entirely?
2. Is there a new recommended way to pass model parameters other than environment variables?
3. Should init_app() be updated to accept and forward kwargs to model initialization?

Proposed Solutions

Option A: Restore kwargs functionality

app = init_app(
    model_class=YOLO,
    model_kwargs=kwargs,  # Pass kwargs to init_app
    basic_auth_user=args.basic_auth_user,
    basic_auth_pass=args.basic_auth_pass,
)

Option B: Remove misleading argument parsing

• Remove --with and --kwargs options if they're no longer supported
• Update documentation to reflect current capabilities

Environment

• Affected files: All *_wsgi.py files in examples/
• Configuration methods: Both --with flag and config.json affected
• Impact: High - breaks existing workflows that rely on model customization

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Labels: bug, breaking-change, configuration, wsgi

[WillieMaddox]

Seems like this has been a problem for a while #248

[heidi-humansignal]

Hello WillieMaddox,

Have you tried deploying ml-backend with docker and seeing if you run into this error?

Thank you,
Abu

Comment by Abubakar Saad
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