add CSV-separated job run causes to RunMessage

[jordanglassman]

Description

Adds a CSV-separated list of run cause simple class names for downstream consumers to decide if they want to consume these events or not.

Submitter checklist

• Link to JIRA ticket in description, if appropriate.
• Change is code complete and matches issue description
• Appropriate unit or acceptance tests or explanation to why this change has no tests
• Reviewer's manual test instructions provided in PR description. See Reviewer's first task below.

Reviewer checklist

• Run the changes and verified the change matches the issue description
• Reviewed the code
• Verified that the appropriate tests have been written or valid explanation given

[tfennelly]

Might want to wrap all of this in a check for null on the return of run.getCauses().

[jordanglassman]

#getCauses is tagged @Nonnull and looks safe:

public @Nonnull List<Cause> getCauses() {
        CauseAction a = getAction(CauseAction.class);
        if (a==null)    return Collections.emptyList();
        return Collections.unmodifiableList(a.getCauses());
    }

[jordanglassman]

@tfennelly ping?

[tfennelly]

So this will be added on every event, right? I'd restrict it just the run_started event.

[jordanglassman]

@tfennelly any objections to going forward with this?

[jordanglassman]

@tfennelly updated with recommended change.

[tfennelly]

Look good @jordanglassman

Would be important to test these changes in a Jenkins that has Blue Ocean installed.

[tfennelly]

Also of course ... the CI is failing there atm.

[jordanglassman]

@tfennelly I've tested this in all the ways I know how.

Blue Ocean acceptance tests pass, and works with local testing. LMK what the next step for moving this ball forward is?