Scriptworker hangs if script writes really long line

[tomprince]

If a balrogworker submit-toplevel task is re-run after all the balrog submit jobs, then the blob printed out by balrogclient here is on the order of 600k. This cause the log processing on scriptworker to hang (or something). Balrogscript currently writes logs synchronously, which meant it hung trying to write the log.

[escapewindow]

Hm. Should we document this, wrap, truncate, throw an exception, or other? I think the middle 3 solutions require us to check the length of each log line.

Finding out what is hanging and fixing it might be the best solution. We may want to add a test case to make sure we don't regress in that case.