Task 003: add postgres schema and seed data

apps/backend/alembic/env.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+
+import os
+import sys
+from logging.config import fileConfig
+from pathlib import Path
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+
+BACKEND_ROOT = Path(__file__).resolve().parents[1]
+for import_root in (BACKEND_ROOT, BACKEND_ROOT.parents[1]):
+    if (import_root / "src").exists():
+        sys.path.insert(0, str(import_root))
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = None
+
+
+def _database_url() -> str:
+    configured = os.environ.get("DATABASE_URL") or os.environ.get("POSTGRES_DSN")
+    if not configured:
+        return config.get_main_option("sqlalchemy.url")
+
+    if configured.startswith("postgresql://"):
+        return "postgresql+psycopg://" + configured.removeprefix("postgresql://")
+    if configured.startswith("postgres://"):
+        return "postgresql+psycopg://" + configured.removeprefix("postgres://")
+    return configured
+
+
+def run_migrations_offline() -> None:
+    context.configure(
+        url=_database_url(),
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    configuration = config.get_section(config.config_ini_section, {})
+    configuration["sqlalchemy.url"] = _database_url()
+    connectable = engine_from_config(
+        configuration,
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(connection=connection, target_metadata=target_metadata)
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()