Add error details for failed remote job

[pauljxtan]

Context:

Currently, a failed remote job produces a generic error message that is difficult to diagnose. The job info response from the remote platform contains a meta field that is currently unused, but has some information that may be useful, e.g.,

{
    'error_code': 'hardware-message-error',
    'error_detail': 'The job failed because the message received from the hardware could not be understood.'
}

Description of the Change:

• Add a meta property to the Job class. In the event of job failure, this dictionary will contain an error-code and error-detail.
• Refresh the meta attribute (along with status) when Job.refresh() is called.
• Add the contents of meta to the error message for a failed job.

Example:

• Previous error message: "The remote job 928ee53e-677a-48c0-8ba5-a0566ba3e295 failed due to an internal server error. Please try again."
• New error message: "The remote job 928ee53e-677a-48c0-8ba5-a0566ba3e295 failed due to an internal server error. Please try again. {'error_code': 'hardware-message-error', 'error_detail': 'The job failed because the message received from the hardware could not be understood.'}"

Benefits:

The added context in a copy-pastable error message is likely to make it easier to diagnose and debug job failures.

Possible Drawbacks:

The new error message is slightly verbose.

Related GitHub Issues:

N/A

[codecov[bot]]

Codecov Report

Merging #370 into master will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #370   +/-   ##
=======================================
  Coverage   97.69%   97.70%           
=======================================
  Files          52       52           
  Lines        6478     6485    +7     
=======================================
+ Hits         6329     6336    +7     
  Misses        149      149           

Impacted Files	Coverage Δ
strawberryfields/api/connection.py	100.00% <ø> (ø)
strawberryfields/engine.py	94.90% <ø> (ø)
strawberryfields/api/job.py	94.11% <100.00%> (+0.93%)	:arrow_up:

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[pauljxtan]

Just FYI, @lneuhaus and I coordinated an end-to-end test for a deliberately failing job and didn't find any problems.

[antalszava]

Thanks so much for this @pauljxtan, looks really good! :100: Had a couple of suggestions which might be improvements to add, but I'm also happy with the current state.