Move dev DB schema creation and stamping to a separate process

.cookiecutter/includes/conf/supervisord-dev.conf.json

@@ -1,5 +1,9 @@
 {
   "programs": {
+    "make_db": {
+      "command": "bin/make_db",
+      "startsecs": "0"
+    },
     "web": {
       "command": "gunicorn -c conf/gunicorn/dev.conf.py --paste conf/development.ini"
     },

bin/make_db

@@ -1,5 +1,35 @@
-"""Initialize the dev environment's DB."""
 #!/usr/bin/env python3
-import sys
+"""Initialize the dev environment's DB."""
+import alembic.command
+import alembic.config
 from pyramid.paster import bootstrap
-bootstrap("conf/development.ini")
+from sqlalchemy import text
+from sqlalchemy.exc import ProgrammingError
+
+from via.db import Base, create_engine
+
+
+def is_stamped(engine) -> bool:
+    """Return True if the DB is stamped with an Alembic revision ID."""
+    with engine.connect() as connection:
+        try:
+            if connection.execute(text("select * from alembic_version")).first():
+                return True
+        except ProgrammingError:
+            pass
+
+    return False
+
+
+def main():
+    with bootstrap("conf/development.ini") as env:
+        settings = env["registry"].settings
+        engine = create_engine(settings)
+
+        if not is_stamped(engine):
+            Base.metadata.create_all(engine)
+            alembic.command.stamp(alembic.config.Config("conf/alembic.ini"), "head")
+
+
+if __name__ == "__main__":
+    main()

conf/supervisord-dev.conf

@@ -2,6 +2,14 @@
 nodaemon=true
 silent=true
 
+[program:make_db]
+command=bin/make_db
+stdout_events_enabled=true
+stderr_events_enabled=true
+stopsignal=KILL
+stopasgroup=true
+startsecs=0
+
 [program:web]
 command=gunicorn -c conf/gunicorn/dev.conf.py --paste conf/development.ini
 stdout_events_enabled=true

via/db.py

@@ -1,8 +1,6 @@
-import alembic.command
-import alembic.config
+import sqlalchemy
 import zope.sqlalchemy
-from sqlalchemy import MetaData, create_engine, text
-from sqlalchemy.exc import ProgrammingError
+from sqlalchemy import MetaData
 from sqlalchemy.orm import DeclarativeBase, MappedAsDataclass, Session
 
 
@@ -18,23 +16,13 @@ class Base(MappedAsDataclass, DeclarativeBase):
     )
 
 
-def stamp(engine):  # pragma: no cover
-    """If the DB isn't already stamped then stamp it with the latest revision."""
-    stamped = False
-
-    with engine.connect() as connection:
-        try:
-            if connection.execute(text("select * from alembic_version")).first():
-                stamped = True
-        except ProgrammingError:
-            pass
-
-    if not stamped:
-        alembic.command.stamp(alembic.config.Config("conf/alembic.ini"), "head")
+def create_engine(settings):  # pragma: no cover
+    """Return a SQLAlchemy engine."""
+    return sqlalchemy.create_engine(settings["database_url"])
 
 
 def includeme(config):  # pragma: no cover
-    engine = create_engine(config.registry.settings["database_url"])
+    engine = create_engine(config.registry.settings)
 
     def db_session(request):
         """Return the SQLAlchemy session for the given request."""
@@ -47,11 +35,6 @@ def db_session(request):
 
         return session
 
-    if config.registry.settings.get("dev"):
-        # Create the database tables if they don't already exist.
-        Base.metadata.create_all(engine)
-        stamp(engine)
-
     # Make the SQLAlchemy session available as `request.db`.
     # `reify=True` means it'll create only one session per request.
     config.add_request_method(db_session, name="db", reify=True)