Distributed Services with Go

What You Learned

Now when our servers discover other servers, they replicate each other’s data. That’s a problem with our replication implementation: when one server discovers another, they replicate each other in a cycle! You can verify it by adding this code at the bottom of your test:

consumeResponse, err = leaderClient.Consume(
 context.Background(),
 &api.ConsumeRequest{
  Offset: produceResponse.Offset + 1,
 },
)
require.Nil(t, consumeResponse)
require.Error(t, err)
got := grpc.Code(err)
want := grpc.Code(api.ErrOffsetOutOfRange{}.GRPCStatus().Err())
require.Equal(t, got, want)

We only produced one record to our service, and yet we’re able to consume multiple records from the original server because it’s replicated data from another ...