♻️ Refactor app_module_setup into Composable Decorators to Enable Modular and Idempotent App Setups

[pcrespov]

What do these changes do?

The app_module_setup decorator is typically used in web applications (like those built with aiohttp) to define setup functions that initialize parts of the application — e.g., routes, background tasks, signals, middleware, etc. These setup functions must be idempotent: they should only run once, even if they are called multiple times (e.g., by different parts of the app or due to reuse of shared components).

✅ Purpose of app_module_setup

• Marks a function as a module setup function.
• Ensures it only runs once per app instance.
• Used to register or configure aspects of the application.
• May allow toggle/setup through config (e.g., optional plugins).

♻️ Why Refactor into Smaller Decorators (e.g., ensure_single_setup)

Refactoring app_module_setup into smaller decorators makes it:

• Composable: Combine different setup constraints or conditions.
• Re-usable: Use ensure_single_setup to guard any function (not just module setup) against multiple calls.
• Split-friendly: Break one big setup into logically separated functions while still ensuring each part only runs once.

🧩 Example: Split Setup with Reusable Guarantees

# Split setup parts
@ensure_single_setup
def setup_routes(app):
    # register routes
    app.router.add_get("/", lambda request: web.Response(text="Hello"))
    
@ensure_single_setup
def setup_events(app):
    # register startup/shutdown signals
    async def on_startup(app): ...
    app.on_startup.append(on_startup)

# High-level setup composed from parts
@app_module_setup("A", ModuleCategory.ADDON, settings_name="WEBSERVER_A")
def setup_module_a(app):
    setup_module_b(app)
    setup_routes(app)
    setup_events(app)
  

# Then during application bootstrapping:
app = web.Application()
setup_module_a(app)
setup_module_b(app) # this is not executed because it was exectued in a

Related issue/s

• Prerequisite for ✨ web-server: Add Stand-alone Auth-App Entrypoint to Web-Server #7818
• Implements parts of ⚗️ web-server refactoring backlog #2008

How to test

cd packages/service-lib
make "install-dev[aiohttp]"
pytest -vv tests/aiohttp/test_application_setup.py

Dev-ops

None

[codecov]

Codecov Report

Attention: Patch coverage is 86.76471% with 9 lines in your changes missing coverage. Please review.

Project coverage is 87.77%. Comparing base (64695c3) to head (76f3cfb).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7982      +/-   ##
==========================================
- Coverage   87.88%   87.77%   -0.12%     
==========================================
  Files        1841     1423     -418     
  Lines       71051    59192   -11859     
  Branches     1228      627     -601     
==========================================
- Hits        62444    51953   -10491     
+ Misses       8252     7028    -1224     
+ Partials      355      211     -144     

Flag	Coverage Δ
integrationtests	64.30% <100.00%> (+0.10%)	⬆️
unittests	86.08% <86.76%> (-0.40%)	⬇️

Components	Coverage Δ
api	∅ <ø> (∅)
pkg_aws_library	∅ <ø> (∅)
pkg_celery_library	∅ <ø> (∅)
pkg_dask_task_models_library	∅ <ø> (∅)
pkg_models_library	∅ <ø> (∅)
pkg_notifications_library	∅ <ø> (∅)
pkg_postgres_database	∅ <ø> (∅)
pkg_service_integration	∅ <ø> (∅)
pkg_service_library	71.63% <86.15%> (+0.06%)	⬆️
pkg_settings_library	∅ <ø> (∅)
pkg_simcore_sdk	85.05% <ø> (-0.06%)	⬇️
agent	96.29% <ø> (ø)
api_server	92.64% <ø> (ø)
autoscaling	96.03% <ø> (ø)
catalog	92.29% <ø> (ø)
clusters_keeper	99.13% <ø> (ø)
dask_sidecar	92.35% <ø> (ø)
datcore_adapter	97.94% <ø> (ø)
director	76.73% <ø> (ø)
director_v2	91.08% <ø> (-0.03%)	⬇️
dynamic_scheduler	96.69% <ø> (ø)
dynamic_sidecar	90.09% <ø> (ø)
efs_guardian	89.65% <ø> (ø)
invitations	93.60% <ø> (ø)
payments	92.57% <ø> (ø)
resource_usage_tracker	89.10% <ø> (+0.10%)	⬆️
storage	86.23% <ø> (ø)
webclient	∅ <ø> (∅)
webserver	87.63% <100.00%> (+<0.01%)	⬆️

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[Copilot]

Pull Request Overview

This PR refactors the legacy app_module_setup decorator into smaller, composable decorators to improve modularity and enforce idempotent application setup routines.

• Introduces ensure_single_setup to guard any setup function against multiple executions per app.
• Adds _SetupTimingContext for consistent timing and logging around setups.
• Rewrites app_module_setup to compose the new decorators and simplify internal logic.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/service-library/tests/aiohttp/test_application_setup.py	Updated and extended tests to cover ensure_single_setup, adjusted fixtures.
packages/service-library/src/servicelib/aiohttp/application_setup.py	Extracted idempotency logic into ensure_single_setup, added timing context, and restructured app_module_setup.

Comments suppressed due to low confidence (5)

packages/service-library/src/servicelib/aiohttp/application_setup.py:23

• There is an extra space before the dot in the f-string, resulting in a storage key with an unintended space. It should be f"{__name__}.setup".

APP_SETUP_COMPLETED_KEY: Final[str] = f"{__name__ }.setup"

packages/service-library/src/servicelib/aiohttp/application_setup.py:180

• [nitpick] Use the instance logger (self.logger) instead of the module‐level _logger here so that exit logs go through the same logger passed into the context.

            _logger.info("%s completed [Elapsed: %3.1f secs]", self.head_msg, elapsed)

packages/service-library/src/servicelib/aiohttp/application_setup.py:206

• The decorator uses functools.wraps but functools is not imported in this module, causing a NameError. Add import functools at the top.

        @functools.wraps(setup_func)

packages/service-library/src/servicelib/aiohttp/application_setup.py:305

• [nitpick] This assertion forces all setup functions to start with setup_, which conflicts with fixtures or helpers named _setup_*. Consider relaxing or removing this constraint or renaming impacted functions.

        assert setup_func.__name__.startswith(  # nosec

packages/service-library/tests/aiohttp/test_application_setup.py:168

• [nitpick] The test hardcodes '<Application. Avoid logging objects like this>' as the app repr, which won’t match actual output. Either mock the app’s __repr__ or loosen the assertion to avoid a fragile placeholder.

        "'test.module' was already initialized in <Application. Avoid logging objects like this>. Setup can only be executed once per app.",

[pcrespov]

@mergify queue

[mergify]

queue

🛑 The pull request has been merged manually

The pull request has been merged manually at e7d9064

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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