Raise warning if instance limit is reached

[kt474]

Summary

Adding warnings before job submission if the instance limit has been reached.

Details and comments

Fixes #2453

[kt474]

FYI @francabrera

[ElePT]

I added one quick question, and I agree that it would be good to get an additional review from @francabrera.

[ElePT]

One question, what if usage_dict.get("usage_limit_seconds") is 0? In this case I believe that not usage_dict.get("usage_limit_seconds") will evaluate to True, but according to the issue we only want it to evaluate to True if the value is None. Did I follow this correctly?

[diego-plan9]

I agree with you on how the 0 case will be handled - depending on how the above conversation evolves, this line might not be present anymore.

[francabrera]

I don't understand why usage_allocation_seconds is used here? If the instance is limited the limit will be usage_limit_seconds.

If it's there is no limit in the instance, but usage_limit_reached is true, then we always display the message for the instance's plan on the account.

[diego-plan9]

It seems related to #1829 - the logic for the existing usage() method also involves usage_allocation_seconds():

qiskit-ibm-runtime/qiskit_ibm_runtime/qiskit_runtime_service.py

Lines 1185 to 1199 in d03882d

	def usage(self) -> Dict[str, Any]:
	"""Return usage information for the current active instance.
	Returns:
	Dict with usage details.
	"""
	usage_dict = self._active_api_client.cloud_usage()
	if usage_dict.get("usage_limit_seconds") or usage_dict.get("usage_allocation_seconds"):
	usage_remaining = max(
	usage_dict.get("usage_limit_seconds", usage_dict.get("usage_allocation_seconds"))
	- usage_dict.get("usage_consumed_seconds", 0),
	0,
	)
	usage_dict["usage_remaining_seconds"] = usage_remaining
	return usage_dict

@francabrera , can you verify that taking into account usage_allocation_seconds (if usage_limit_seconds) for the calculation is correct? If it is, I think we can just take advantage of the existing method and piggyback on it.

[diego-plan9]

Continuing this PR from Kevin (thanks!) - in d8c778b:

• revised the logic to hopefully take into account review comments
• made use of QiskitRuntimeService::usage() for reusing the interface (rather than on the raw API call)
• added an extra entry to the test