Should cylc config be able to report the configuration being used by a running workflow?

[dpmatthews]

Given a workflow id, cylc config prints the "workflow configuration" (according to the help text).
But what does that really mean?
What (I think) it means is that it parses whatever configuration files it finds in the workflow directory.
However, this may be very different from the configuration in use by a running workflow because:
a) the config may have been changed by reinstall but not reloaded
b) the config may have been altered via cylc play options (--set #4740, --fcp, etc)

The parsed config file is recorded in the log/flow-config directory.
This includes the result of any --set options although note that it still doesn't reflect any changes made by --fcp for example.
(See also #4755)

The Rose fcm make built-in app uses cylc config to check for the existence of "fcm_make2" tasks.
In theory it could get the wrong result because it is not actually querying the configuration in use.
In practise this is very unlikely and not worth worrying about for this legacy use case.
However, it does raise the question: do we need the ability to query the configuration being used by a running workflow?

[hjoliver]

However, it does raise the question: do we need the ability to query the configuration being used by a running workflow?

Good point. I think we should, ideally. However, we could have another file in the run-directory that records the config of the (latest) running scheduler, rather than literally query the scheduler.

[oliver-sanders]

• Broadcasts alter the config in memory but not on disk.
• We could allow the workflow config to be queried via GraphQL.
• We need to be able to query the [runtime] section for Re-implement edit-run #3751.
• Does the fcm_make2 issue require [scheduling] information or is [runtime] sufficient?

[dpmatthews]

Does the fcm_make2 issue require [scheduling] information or is [runtime] sufficient?

I think [runtime] is sufficient but I'm really not worried about this use case.

[oliver-sanders]

I don't think cylc config needs to be able to display the running config (note we get a file in log/config on reload), but we might want to open up an interface via GraphQL for other purposes.

Can we bump this to 8.x?

[hjoliver]

Broadcasts alter the config in memory but not on disk.

We could potentially write every config change to disk, for provenance reasons. Short of that though, getting current active config via GraphQL would be fine IMO.

[hjoliver]

Can we bump this to 8.x?

I don't this is super urgent, I'll bump it.