[I] Python driver: No public API for connection pooling / external connection management [age]

["uesleilima (via GitHub)" <gi...@apache.org>]

uesleilima opened a new issue, #2369:
URL: https://github.com/apache/age/issues/2369

   **Is your feature request related to a problem?**
   
   The `Age` class and `Age.connect()` create and own a single `psycopg.Connection` internally. In production applications that need connection pooling (via `psycopg_pool.ConnectionPool` or similar), there is no supported way to:
   
   1. Register agtype adapters on externally-managed connections.
   2. Use a pool's `configure` callback to set up AGE on each new connection.
   3. Pass a pre-existing connection into the `Age` wrapper.
   4. Access `AgeLoader` and `ClientCursor` without reaching into private module attributes (`age.age.AgeLoader`, `age.age.ClientCursor`).
   
   The only option is to replicate the driver's internal setup logic manually, which is fragile and tightly coupled to implementation details.
   
   **Current workaround**
   
   ```python
   import age
   import psycopg
   from psycopg.types import TypeInfo
   from psycopg_pool import ConnectionPool
   
   def _configure_age_connection(conn):
       """Per-connection AGE setup — replicates driver internals."""
       with conn.cursor() as cur:
           cur.execute('SET search_path = ag_catalog, "$user", public;')
   
       ag_info = TypeInfo.fetch(conn, "agtype")
       if ag_info is None:
           raise RuntimeError("AGE agtype type not found")
   
       # These are private module attributes — no public API exists
       conn.adapters.register_loader(ag_info.oid, age.age.AgeLoader)       # type: ignore
       conn.adapters.register_loader(ag_info.array_oid, age.age.AgeLoader)  # type: ignore
       conn.commit()
   
   pool = ConnectionPool(
       conninfo="host=localhost dbname=mydb",
       configure=_configure_age_connection,
       kwargs={"cursor_factory": age.age.ClientCursor},  # type: ignore
   )
   pool.open()
   ```
   
   This works, but relies on `age.age.AgeLoader` and `age.age.ClientCursor` which are not part of any documented public API and require `# type: ignore` to satisfy type checkers.
   
   **Describe the solution you'd like**
   
   Expose a public function that configures an existing connection for AGE use, without creating a new connection or running `LOAD 'age'`:
   
   ```python
   # Proposed API
   def configure_connection(conn, graph_name=None, skip_load=False):
       """Register agtype adapters on an existing connection.
   
       Sets search_path, fetches agtype OIDs, and registers AgeLoader.
       Optionally checks/creates the graph.
   
       This enables use with external connection pools.
       """
       ...
   ```
   
   Additionally, export `AgeLoader` and `ClientCursor` as documented public symbols (e.g., via `__all__` in `__init__.py` or as top-level imports).
   
   **Describe alternatives you've considered**
   
   - Monkeypatching `Age.connect()` to accept an existing connection — fragile.
   - Subclassing `Age` to override connection creation — the class was not designed for inheritance.
   
   Related: #2353 (skip_load parameter) addresses part of this by making `setUpAge()` work on managed PostgreSQL, but even with that fix, there is no clean way to use the driver with a connection pool.
   
   **Environment**
   
   - Python driver: master branch (psycopg3 version)
   - psycopg: 3.2.x
   - psycopg_pool: 3.2.x


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Re: [I] Python driver: No public API for connection pooling / external connection management [age]

["jrgemignani (via GitHub)" <gi...@apache.org>]

jrgemignani closed issue #2369: Python driver: No public API for connection pooling / external connection management
URL: https://github.com/apache/age/issues/2369


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