flux-jobs: support output format to show exception notes

[chu11]

While trying to write up a simple tutorial on flux job cancel, I realized that we have no easy way for users to check for exception notes other than writing their own format in flux jobs. This is fine, but exceptions are a bit long to write formats for.

A format for listing failure information in flux jobs would probably be useful when users run flux job --filter=failed or flux job --filter=canceled. Perhaps something like:

{id} {user} {name} {result} {exception.severity} {exception.type} {exception.note}

Maybe could throw {returncode} in as well.

[grondo]

Maybe could throw {returncode} in as well.

What about a new "contextual" field in JobInfo that returns the "exit reason" (we could actually call it exit_reason though that could be confusing because not all inactive jobs actually exited), i.e. if the job is inactive it returns some text describing the exception if one occurred, otherwise a string with the return code, perhaps in shell-like form, e.g. Exit 0, Exit 1, Killed, Terminated, etc. Then we might have room for start and end times which might be nice.

[chu11]

What about a new "contextual" field in JobInfo that returns the "exit reason" (we could actually call it exit_reason though that could be confusing because not all inactive jobs actually exited), i.e. if the job is inactive it returns some text describing the exception if one occurred, otherwise a string with the return code, perhaps in shell-like form, e.g. Exit 0, Exit 1, Killed, Terminated, etc. Then we might have room for start and end times which might be nice.

Oh that's a good idea.