// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.cobalt;

// The Controller is primarily useful for testing the Cobalt service.
// Cobalt clients should use the Logger.

[Discoverable]
interface Controller {
    // Requests that the collection of Observations that are currently cached
    // locally be sent to the Cobalt server soon. Cobalt will send the
    // Observations in one or more batches and will retry several times upon
    // failure. The response occurs only after that procedure is completed. A
    // return value of true indicates that all Observations were successfully
    // sent. A return value of false indicates otherwise.
    1: RequestSendSoon() -> (bool success);

    // The Cobalt FIDL service will block, not processing any further FIDL
    // requests or responses, on either this interface or the Logger interface,
    // until either |max_wait_seconds| have elapsed or the Cobalt service's
    // worker thread has successfully sent all previously added Observations to
    // the Shuffler. The response will be returned after the blocking period has
    // ended. Note that this method does not request an expedited send and so it
    // is possible that the worker thread is currently waiting for the next
    // scheduled send time and so the empty state will not be achieved prior
    // that time.
    2: BlockUntilEmpty(uint32 max_wait_seconds) -> ();

    // These diagnostic stats are mostly useful in a testing environment but
    // may possibly prove useful in production also.
    3: GetNumSendAttempts() -> (uint32 num);
    4: GetFailedSendAttempts() -> (uint32 num);
};