application_name doesn't seem accepted

[hydrargyrum]

• asyncpg version: 0.23.0
• PostgreSQL version: 12.3
• **Do you use a PostgreSQL SaaS? **: false
• Python version: 3.9
• Platform:
• Do you use pgbouncer?: false
• Did you install asyncpg with pip?: true
• If you built asyncpg locally, which version of Cython did you use?:
• Can the issue be reproduced under both asyncio and
  uvloop?:

taking some code written by zzzeek himself https://stackoverflow.com/a/15691283:

create_async_engine(f"postgresql+asyncpg://{user}:{password}@{hostname}/{database_name}?application_name={APPNAME}")

yields

E           TypeError: connect() got an unexpected keyword argument 'application_name'

using instead something I found in an issue here #204

    create_async_engine(
        f"postgresql+asyncpg://{user}:{password}@{hostname}/{database_name}",
        server_settings={"application_name": APPNAME},
    )

yields instead

E           TypeError: Invalid argument(s) 'server_settings' sent to create_engine(), using configuration PGDialect_asyncpg/AsyncAdaptedQueuePool/Engine.  Please check that the keyword arguments are appropriate for this combination of components.

[elprans]

It would be more appropriate to post this in the SQLAlchemy issue tracker.

[elprans]

That said,

    create_async_engine(
        f"postgresql+asyncpg://{user}:{password}@{hostname}/{database_name}",
        connect_args={"server_settings": {"application_name": APPNAME}},
    )

should work

[hydrargyrum]

It would be more appropriate to post this in the SQLAlchemy issue tracker.

@elprans Why? It's asyncpg which rejects the application_name parameter

[elprans]

It's asyncpg which rejects the application_name parameter

The application_name, like other server-side options should be passed in the server_settings dictionary argument to connect().

In your case, SQLAlchemy is incorrectly interpreting the DSN and tries to pass application_name directly to connect(), and in the explicit argument scenario you should pass it like I've shown above.

[ludaavics]

@CaselIT easy workaround, but FYI this seems still open in 1.4.26

[CaselIT]

I think this is the expected behavior.
psycopg2 (the default postgresql dialect used by sqlalchemy when no dialect is specified) accepts any libpq argument as connection kw parameter, including application_name. see https://www.psycopg.org/docs/module.html#psycopg2.connect
while asyncpg does not, so unless asyncpg gets support you should use the server_settings.

[tuukkamustonen]

A rather old ticket, but anyone know how the application_name is handled? Will passing server_settings={"application_name": "foo"} cause SET application_name='foo' on an opened connection?

Will it do the same with psycopg?

(I'm wondering if that could lead the proxy pinning, e.g. AWS RDS Proxy, which often monitor things like SET ...)