Function _connect

asyncpg/connect_utils.py:1205–1252

(*, loop, connection_class, record_class, **kwargs)

async def _connect(*, loop, connection_class, record_class, **kwargs):
    if loop is None:
        loop = asyncio.get_event_loop()

    addrs, params, config = _parse_connect_arguments(**kwargs)
    target_attr = params.target_session_attrs

    candidates = []
    chosen_connection = None
    last_error = None
    try:
        for addr in addrs:
            try:
                conn = await _connect_addr(
                    addr=addr,
                    loop=loop,
                    params=params,
                    config=config,
                    connection_class=connection_class,
                    record_class=record_class,
                )
                candidates.append(conn)
                if await _can_use_connection(conn, target_attr):
                    chosen_connection = conn
                    break
            except OSError as ex:
                last_error = ex
        else:
            if target_attr == SessionAttribute.prefer_standby and candidates:
                chosen_connection = random.choice(candidates)
    finally:

        async def _close_candidates(conns, chosen):
            await asyncio.gather(
                *(c.close() for c in conns if c is not chosen),
                return_exceptions=True
            )
        if candidates:
            asyncio.create_task(
                _close_candidates(candidates, chosen_connection))

    if chosen_connection:
        return chosen_connection

    raise last_error or exceptions.TargetServerAttributeNotMatched(
        'None of the hosts match the target attribute requirement '
        '{!r}'.format(target_attr)
    )


async def _cancel(*, loop, addr, params: _ConnectionParameters,