In some system tests a Streams app is started and then prints a message to stdout, which the system test waits for to confirm the node has successfully been brought up. It then greps for certain log messages in a retriable loop.
But waiting on the Streams app to start/print to stdout does not mean the log file has been created yet, so the grep may return an error. Although this occurs in a retriable loop it is assumed that grep will not fail, and the result is piped to wc and then blindly converted to an int in the python function, which fails since the error message is a string (throws ValueError)
We should catch the ValueError and return a 0 so it can try again rather than immediately crash
Reviewers: Bill Bejeck <bbejeck@gmail.com>, John Roesler <vvcephei@users.noreply.github.com>, Guozhang Wang <wangguoz@gmail.com>
A. Sophie Blee-Goldman