Russell Owen added a comment - 23/Aug/19 7:46 PM The basic design (as implemented in a preliminary implementation that has since been superseded by more complete code): A command-line script accepts a list of one or more SAL components to listen to. For each SAL component make a ComponentProducer which listens to all messages from that SAL component (using index 0, so all instances). For each topic make a TopicProducer that listens to that one topic. Its callback function produces a kafka message for each DDS sample. The Avro schema is generated by introspecting the DDS sample (with one field added for the time at which the kafka message is produced). Once SAL 4 is released we can parse the IDL files to generate a description and units for each field, though we may well want to continue to generate the rest of the schema the same way we are doing now. One detail: the TopicProducer contains an instance of lsst.ts.salobj.ReadTopic. We cannot use ControllerCommand to listen to commands because we cannot afford to have an ack sent when a command is received. We could use RemoteEvent and RemoteTelemetry for those topics, but it is simpler to treat all topics the same.