Initial commit: LogHive centralized log management system

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/database.py

@@ -0,0 +1,37 @@
+"""Database connections and session management."""
+
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+# ── PostgreSQL ────────────────────────────────────────────────────
+engine = create_async_engine(settings.DATABASE_URL, echo=settings.DEBUG)
+async_session_factory = async_sessionmaker(engine, expire_on_commit=False)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+async def get_db() -> AsyncSession:
+    """Yield a DB session per request."""
+    async with async_session_factory() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()
+
+
+async def init_db() -> None:
+    """Create all tables (use Alembic in production)."""
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+
+async def close_db() -> None:
+    await engine.dispose()