Function proposeOrSend

worker/mutation.go:651–686

proposeOrSend either proposes the mutation if the node serves the group gid or sends it to the leader of the group gid for proposing.

(ctx context.Context, gid uint32, m *pb.Mutations, chr chan res)

// proposeOrSend either proposes the mutation if the node serves the group gid or sends it to
// the leader of the group gid for proposing.
func proposeOrSend(ctx context.Context, gid uint32, m *pb.Mutations, chr chan res) {
	res := res{}
	if groups().ServesGroup(gid) {
		res.ctx = &api.TxnContext{}
		res.err = (&grpcWorker{}).proposeAndWait(ctx, res.ctx, m)
		chr <- res
		return
	}

	pl := groups().Leader(gid)
	if pl == nil {
		res.err = conn.ErrNoConnection
		chr <- res
		return
	}

	var tc *api.TxnContext
	c := pb.NewWorkerClient(pl.Get())

	ch := make(chan error, 1)
	go func() {
		var err error
		tc, err = c.Mutate(ctx, m)
		ch <- err
	}()

	select {
	case <-ctx.Done():
		res.err = ctx.Err()
		res.ctx = nil
	case err := <-ch:
		res.err = err
		res.ctx = tc
	}
	chr <- res
}

// populateMutationMap populates a map from group id to the mutation that
// should be sent to that group.