Activating fileMetric on EventBuilders causes downstream ART modules to fail
John first discovered this issue while trying to run artdaq-demo with the file metric plugins (the example use-case currently in the develop branch of artdaq-demo). When the file metric was enabled, all events from any EventBuilder past the first would not be accessible to the WFViewer or ToyDumper modules. Further investigation showed that the data was actually present in the output file, and that removing the metrics.evbFile.fileName parameter resolved the issue. Kurt remembered that the Aggregator cannot handle multiple EventBuilder configurations, and therefore the FhiCL code sent to the EventBuilders must be identical (the fileName parameter was uniquified in the generateEventBuilder.rb file, triggering this problem).
I have committed code to the file_metric plugin which accepts a uniquify FCL parameter, which then adds the PID to the output file name (uniquifying the file name while maintaining identical FCL configurations).