MeterLogManager throws NPE when metrics are disabled

Environment (Required on creation):

all distributions

Description (Required on creation; please attach any relevant screenshots, stacktraces, log files, etc. to the ticket):

If the application starts with Metrics disabled, the MeterLogManager throws an NPE when migrating a process via batch operation.

Steps to reproduce (Required on creation):

With Metrics disabled via "metricEnabled", migrate a process via batch operation.

Observed Behavior (Required on creation):

A Null Pointer Exception is thrown in the MeterLogManager.

Expected behavior (Required on creation):

No NPE thrown

Root Cause (Required on prioritization):

• With "isMetricEnabled" flag disabled, the DbMetricsReporter is not initialized.

    protected void initMetrics() {
      if (isMetricsEnabled) {
  
        if (metricsRegistry == null) {
          metricsRegistry = new MetricsRegistry();
        }
  
        initDefaultMetrics(metricsRegistry);
  
        if (dbMetricsReporter == null) {
          dbMetricsReporter = new DbMetricsReporter(metricsRegistry, commandExecutorTxRequired);
        }
      }
    }
  

• The MeterLogManager accesses the DbMetricsReporter regardless of the configuration flag

    protected boolean isEndTimeAfterLastReportInterval(MetricsQueryImpl query) {
      long reportingIntervalInSeconds = Context.getProcessEngineConfiguration()
        .getDbMetricsReporter()
        .getReportingIntervalInSeconds();
  
      return (query.getEndDate() == null
          || query.getEndDateMilliseconds()>= ClockUtil.getCurrentTime().getTime() - (1000 * reportingIntervalInSeconds));
    }
  

Solution Ideas (Optional):

The MeterLogManager honors the "isMetricEnabled" flag in the configuration and acts accordingly when disabled.

Hints (optional):