A simple call to DFUGetFileMetaData blocked for nearly 10 minutes. The ESP ultimately provided a "Could not open key file", but by looking at the ESP it seems that error could have been reported to the client much earlier.
let's consider the following. Have a time out between the ESP and whatever back-end component provides the information. If we're performing multiple re-tries, let's allow the client to specify the number of re-tries.
Either way, the client should be able to quickly move on from the failure on the back-end.
Error encoutered on 190:
<Message>2018-01-24 21:45:08 GMT: Could not open key file at //10.239.190.1/var/lib/HPCCSystems/hpcc-data/roxie/images/key/sexoffender/20170602/matrix_images._401_of_401 or any alternate location.</Message>