Hands-On Software Engineering with Golang

Establishing protocol buffer definitions for worker payloads

As we saw in the previous section, we need to define an envelope message for worker payloads:

message WorkerPayload { oneof payload { Step step = 1; RelayMessage relay_message = 2; }}

With the help of the oneof type, we can emulate a message union. A WorkerPayload can contain either a Step message or a RelayMessage message. The Step message is more interesting, so we will examine its definition first:

message Step {  Type type = 1;  map<string, google.protobuf.Any> aggregator_values = 2;  int64 activeInStep = 3;  enum Type {    INVALID = 0;    PRE = 1;    POST = 2;    POST_KEEP_RUNNING = 3;    EXECUTED_GRAPH = 4;    PESISTED_RESULTS = 5;    COMPLETED_JOB = 6;  }}

The Step message will be sent by the worker ...