3. Add device factory decorator with lazy connect support

Date: 2024-04-26

Status

Accepted

Context

We should add a decorator to support verfied device connection.

Decision

DAQ members led us to this proposal:

• ophyd-async: make Device.connect(mock, timeout, force=False) be idempotent

• ophyd-async: make ensure_connected(*devices) plan stub

• dodal: make device_factory(startup_connect=False) decorator that makes, names, caches and optionally connects a device

• dodal: make get_device_factories() that returns all device factories and whether they should be connected at startup

• blueapi: call get_device_factories(), make all the Devices, connect the ones that should be connected at startup in parallel and log those that fail

• blueapi: when plan is called, run ensure_connected on all plan args and defaults that are Devices

We can then iterate on this if the parallel connect causes a broadcast storm. We could also in future add a monitor to a heartbeat PV per device in Device.connect so that it would reconnect next time it was called.

Consequences

The changes above.