@Override
  public void register(String source, ReadableMetricsRegistry registry) {
    this.registries.add(new MetricsRegistryWithSource(source, registry));
    LOG.info("Registering {} with producer.", source);
    this.producer.register(source);
  }
MetricsSnapshotReporter is a generic metrics reporter that sends metrics to a stream.

jobName // my-samza-job
jobId // an id that differentiates multiple executions of the same job
taskName // container_567890
host // eat1-app128.gird
version // 0.0.1
blacklist // Regex of metrics to ignore when flushing
samza-core/src/main/java/org/apache/samza/metrics/reporter/MetricsSnapshotReporter.java