Filters

A filter is an object that can modify and select traces from the log and prepare it for the Discovery (Log processor stage of the data rodeo process).

A filter follows the interface IPMLogSafeFilter, but in order to have a complete implementation it is highly recommended to build the filter inheriting from pm4h.filter.PMLogParallelFilter :

     public interface IPMLogSafeFilter : IPMLogFilter
    {
        Guid ExpId { get; set; }
        IEnumerable<IPMLog> ProcessLog(IEnumerable<IPMLog> _log);
        IEnumerable<IPMLog> ProcessLog(IPMLog _log, IPMLog target);
        IEnumerable<PMTrace> ProcessTrace(PMTrace _trace);
        IEnumerable<PMTrace> ProcessTrace(PMTrace _trace, TraceMetadata md);
        IEnumerable<PMEvent> ProcessEvent(PMEvent _event);
        IEnumerable<PMEvent> ProcessEvent(PMEvent _event, TraceMetadata md);
        IPMLogFilter Clone();
    }

The following figure shows the main properties of the Log, Traces and Events

This filter has some methods that can be overriden in order to change the behavior of the filter.

• The ProcessLog method starts the filtering process, receiving a set of logs as input. Logs are processed sequentially.
• The ProcessTrace method is called for each trace inside a log. All the trace modifications should be performed in this method. The method receives as input:
  • the trace to be processed, and a
  • threadsafe Metadata object called TraceMetadata that allows the sharing of data between Trace and Events.

important

PMLogParallelFilter executes this method in several threads so it is not possible to update data out of this method. Otherwise a thread exception will be thrown.

• The ProcessEvent method is called for each event inside a trace. Events are processed sequentially. All the event modifications should be performed in this method. The method receives as input
  • the event, and a
  • threadsafe Metadata object called TraceMetadata that allows the sharing of data between Trace and Events.

info

By default, the number of threads in the PMLogParallelFilter is 4, but it can be changed by modifying the Maxthreads property of the class.

tip

For debugging Maxthreads can be changed to 1 in order to avoid parallelism during the execution.

Example:

    public class DeleteVoidTracesFilter : PMLogParallelFilter
    {

        public override IEnumerable<IPMLog> ProcessLog(IEnumerable<IPMLog> _log)
        {
            foreach (var l in base.ProcessLog(_log))
            {
                if (l.Count() > 0)
                {
                    yield return l;
                }
            }

        }

        public override IEnumerable<PMTrace> ProcessTrace(PMTrace _trace)
        {
            foreach (var t in base.ProcessTrace(_trace))
            {
                if (t.Events.Count > 0)
                {
                    yield return t;
                }
            }
        }

        public override IEnumerable<PMEvent> ProcessEvent(PMEvent _event)
        {
            if (_event.ActivityName != null && _event.ActivityName != "")
            {
                yield return _event;
            }
        }
    }

Emit messages in the Ingestor Report

To emit messages in the ingestor report it is needed to call the static function Warning of the class ExtractionReportDataWareHouse

Sintaxis:
ExtractionReportDataWareHouse.Warning([Experiment ID], [WarningLevel], [Message]);


Example:
ExtractionReportDataWareHouse.Warning(ExpId, WarningLevel.SkippedData, $"Trace {t.SampleId} is not according the model: {t.ToTimeString()}");