Depot library has built-in instrumentation with statsd support. Sinks can have their own metrics, and they will be emmited while using sink connector library into other applications.
Total number of bigquery API operation performed
Time taken for bigquery API operation performed
Total numbers of error occurred on bigquery insert operation
Total number of bigtable insert/update operation performed
Time taken for bigtable insert/update operation performed
Total numbers of error occurred on bigtable insert/update operation