setup multy db suport

python/orm/common.py

@@ -0,0 +1,51 @@
+"""Shared ORM definitions."""
+
+from __future__ import annotations
+
+from os import getenv
+from typing import cast
+
+from sqlalchemy import create_engine
+from sqlalchemy.engine import URL, Engine
+
+NAMING_CONVENTION = {
+    "ix": "ix_%(table_name)s_%(column_0_name)s",
+    "uq": "uq_%(table_name)s_%(column_0_name)s",
+    "ck": "ck_%(table_name)s_%(constraint_name)s",
+    "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
+    "pk": "pk_%(table_name)s",
+}
+
+
+def get_connection_info(name: str) -> tuple[str, str, str, str, str | None]:
+    """Get connection info from environment variables."""
+    database = getenv(f"{name}_DB")
+    host = getenv(f"{name}_HOST")
+    port = getenv(f"{name}_PORT")
+    username = getenv(f"{name}_USER")
+    password = getenv(f"{name}_PASSWORD")
+
+    if None in (database, host, port, username):
+        error = f"Missing environment variables for Postgres connection.\n{database=}\n{host=}\n{port=}\n{username=}\n"
+        raise ValueError(error)
+    return cast("tuple[str, str, str, str, str | None]", (database, host, port, username, password))
+
+
+def get_postgres_engine(*, name: str = "POSTGRES", pool_pre_ping: bool = True) -> Engine:
+    """Create a SQLAlchemy engine from environment variables."""
+    database, host, port, username, password = get_connection_info(name)
+
+    url = URL.create(
+        drivername="postgresql+psycopg",
+        username=username,
+        password=password,
+        host=host,
+        port=int(port),
+        database=database,
+    )
+
+    return create_engine(
+        url=url,
+        pool_pre_ping=pool_pre_ping,
+        pool_recycle=1800,
+    )