Jun 26 MT-0 phase

control/base.py

@@ -0,0 +1,75 @@
+"""
+control/base.py
+---------------
+Standalone SQLAlchemy foundation for the control plane.
+
+`ControlBase` keeps control-plane table metadata fully separate from the
+tenant-schema models declared on `app.db.Model`. The engine is built lazily
+from the `CONTROL_DATABASE_URL` environment variable.
+"""
+
+import os
+from contextlib import contextmanager
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import declarative_base, sessionmaker
+
+# Every control model subclasses this base — its own metadata collection.
+ControlBase = declarative_base()
+
+
+def get_control_database_url() -> str:
+    """Return CONTROL_DATABASE_URL or raise a clear error if unset."""
+    url = os.environ.get('CONTROL_DATABASE_URL')
+    if not url:
+        raise RuntimeError(
+            "CONTROL_DATABASE_URL is not set. Example: "
+            "mysql+pymysql://jqc_control:password@localhost/jqc_control"
+        )
+    return url
+
+
+_engine = None
+_Session = None
+
+
+def get_engine():
+    """Lazily build (and cache) the control-plane engine."""
+    global _engine
+    if _engine is None:
+        _engine = create_engine(
+            get_control_database_url(),
+            pool_pre_ping=True,
+            pool_recycle=1800,
+            future=True,
+        )
+    return _engine
+
+
+def get_sessionmaker():
+    """Lazily build (and cache) the control-plane sessionmaker."""
+    global _Session
+    if _Session is None:
+        _Session = sessionmaker(
+            bind=get_engine(), future=True, expire_on_commit=False
+        )
+    return _Session
+
+
+@contextmanager
+def control_session():
+    """Context-managed session — commits on success, rolls back on error.
+
+    Usage:
+        with control_session() as s:
+            s.add(obj)
+    """
+    session = get_sessionmaker()()
+    try:
+        yield session
+        session.commit()
+    except Exception:
+        session.rollback()
+        raise
+    finally:
+        session.close()