Restructure prepare_server to work similar to make_app

Also, modularize, add comments, load config earlier.

Author: lukasjuhrich

docker-compose.base.yml

@@ -44,6 +44,8 @@ services:
       SWDD_HASH_KEY: key
       MAIL_CONFIRM_URL: "http://localhost/sipa/register/confirm/{}"
       PASSWORD_RESET_URL: "http://localhost/sipa/reset-password/{}"
+      # alternative: `scripts.server_run:prepare_server(echo=True)`
+      FLASK_APP: scripts.server_run:prepare_server
       FLASK_ENV: development
   dev:
     extends: dev-base

docker-compose.dev.yml

@@ -25,7 +25,7 @@ services:
           - app
     ports:
       - "5000:5000"
-    command: ["http", "--debug"]
+    command: ["shell", "flask", "run", "--debug", "--host=0.0.0.0"]
     healthcheck:
       test: curl --fail http://localhost:5000
       interval: 2s

scripts/server_run.py

@@ -3,24 +3,24 @@
 # This file is part of the Pycroft project and licensed under the terms of
 # the Apache License, Version 2.0. See the LICENSE file for details.
 
-import argparse
 import logging
 import os
 import sys
 import time
-from collections.abc import Callable
 
 from babel.support import Translations
 from flask import g, request
 from flask.globals import request_ctx
+from sqlalchemy import create_engine
 from sqlalchemy.orm import scoped_session, sessionmaker
+from sqlalchemy.ext.declarative import DeferredReflection
 from werkzeug.middleware.profiler import ProfilerMiddleware
 
 import pycroft
 import web
 from pycroft.helpers.i18n import set_translation_lookup, get_locale
 from pycroft.model.session import set_scoped_session
-from scripts.connection import try_create_connection, get_connection_string
+from scripts.connection import get_connection_string
 from scripts.schema import AlembicHelper, SchemaStrategist
 from web import make_app, PycroftFlask
 
@@ -30,103 +30,74 @@
 )
 
 
-def prepare_server(args) -> tuple[PycroftFlask, Callable]:
-    """returns both the prepared app and a callback executing `app.run`"""
-    if args.echo:
+def prepare_server(echo=False) -> PycroftFlask:
+    if echo:
         logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
         logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
         logging.getLogger('sqlalchemy.pool').setLevel(logging.DEBUG)
-    app = make_app(args.debug)
-
     logging.getLogger('pycroft').addHandler(default_handler)
 
-    wait_for_db: bool = args.wait_for_database
-
-    connection_string = get_connection_string()
-    connection, engine = try_create_connection(connection_string, wait_for_db, app.logger,
-                                               reflections=False)
-
-    state = AlembicHelper(connection)
-    if args.force_schema_create:
-        strategy = SchemaStrategist(state).create_then_stamp
-    else:
-        strategy = SchemaStrategist(state).determine_schema_strategy()
-    strategy()
-
-    @app.before_request
-    def get_time():
-        g.request_time = time.time()
-
-    @app.teardown_request
-    def time_response(exception=None):
-        request_time = g.pop('request_time', None)
-
-        if request_time:
-            time_taken = time.time() - request_time
-            if time_taken > 0.5:
-                app.logger.warning(
-                    "Response took %s seconds for request %s",
-                    time_taken, request.full_path,
-                )
-
-    connection, engine = try_create_connection(connection_string, wait_for_db, app.logger,
-                                               args.profile)
+    app = make_app()
+    # TODO rename to `default_config.toml`
+    app.config.from_pyfile("flask.cfg")
 
+    engine = create_engine(get_connection_string())
+    with engine.connect() as connection:
+        _ensure_schema_up_to_date(connection)
+    _setup_simple_profiling(app)
+    DeferredReflection.prepare(engine)  # TODO for what is this used?
     set_scoped_session(
         scoped_session(
             sessionmaker(bind=engine),
             scopefunc=lambda: request_ctx._get_current_object(),
         )
     )
+    _setup_translations()
+    if app.config.get("PROFILE", False):
+        app.wsgi_app = ProfilerMiddleware(app.wsgi_app, restrictions=[30])
+    return app
 
+
+def _ensure_schema_up_to_date(connection):
+    state = AlembicHelper(connection)
+    strategy = SchemaStrategist(state).determine_schema_strategy()
+    strategy()
+
+
+def _setup_translations():
     def lookup_translation():
         ctx = request_ctx
         if ctx is None:
             return None
-        translations = getattr(ctx, 'pycroft_translations', None)
+        translations = getattr(ctx, "pycroft_translations", None)
         if translations is None:
             translations = Translations()
             for module in (pycroft, web):
+                # TODO this has a bug. The intention is to merge
+                # `pycroft.translations` and `web.translations`,
+                # but the `os.path.dirname(…)` result is nowhere used.
                 os.path.dirname(module.__file__)
-                dirname = os.path.join(ctx.app.root_path, 'translations')
+                dirname = os.path.join(ctx.app.root_path, "translations")
                 translations.merge(Translations.load(dirname, [get_locale()]))
             ctx.pycroft_translations = translations
         return translations
 
     set_translation_lookup(lookup_translation)
-    app.config.from_pyfile('flask.cfg')
-    if args.profile:
-        app.config['PROFILE'] = True
-        app.wsgi_app = ProfilerMiddleware(app.wsgi_app, restrictions=[30])
-    return app, lambda: app.run(
-        debug=args.debug,
-        port=args.port,
-        host=args.host,
-        threaded=True,
-        exclude_patterns=["**/lib/python3*"],
-    )
 
 
-def create_parser() -> argparse.ArgumentParser:
-    parser = argparse.ArgumentParser(description="Pycroft launcher")
-    parser.add_argument("--debug", action="store_true",
-                        help="run in debug mode")
-    parser.add_argument("--echo", action="store_true",
-                        help="log sqlalchemy actions")
-    parser.add_argument("--profile", action="store_true",
-                        help="profile and log sql queries")
-    parser.add_argument("--exposed", action="store_const", const='0.0.0.0',
-                        dest='host', help="expose server on network")
-    parser.add_argument("-p", "--port", action="store",
-                        help="port to run Pycroft on", type=int, default=5000)
-    parser.add_argument("-w", "--wait-for-database", type=int, default=30,
-                        help="Maximum time to wait for database to become "
-                             "available. Use 0 to wait forever.")
-    parser.add_argument("--force-schema-create", action='store_true')
-    return parser
-
-
-app, run_callable = prepare_server(create_parser().parse_args())
-
-if __name__ == "__main__":
-    run_callable()
+def _setup_simple_profiling(app):
+    @app.before_request
+    def get_time():
+        g.request_time = time.time()
+
+    @app.teardown_request
+    def time_response(exception=None):
+        request_time = g.pop('request_time', None)
+
+        if request_time:
+            time_taken = time.time() - request_time
+            if time_taken > 0.5:
+                app.logger.warning(
+                    "Response took %s seconds for request %s",
+                    time_taken, request.full_path,
+                )

web/app.py

@@ -83,10 +83,9 @@ def maybe_add_config_from_env(self, keys: t.Iterable[str]) -> None:
                 self.logger.debug("Config key %s successfuly read from environment", key)
 
 
-def make_app(debug: bool = False, hades_logs: bool = True) -> PycroftFlask:
+def make_app(hades_logs: bool = True) -> PycroftFlask:
     """Create and configure the main? Flask app object"""
     app = PycroftFlask(__name__)
-    app.debug = debug
 
     # initialization code
     login_manager.init_app(app)
@@ -104,6 +103,8 @@ def make_app(debug: bool = False, hades_logs: bool = True) -> PycroftFlask:
     template_filters.register_filters(app)
     template_tests.register_checks(app)
 
+    # NOTE: this is _only_ used for its datetime formatting capabilities,
+    # for translations we have our own babel interface in `pycroft.helpers.i18n.babel`!
     Babel(app)
     if hades_logs:
         try: