google.golang.org/grpc@v1.74.2/xds/internal/testutils/resource_watcher.go (about)

     1  /*
     2   *
     3   * Copyright 2023 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  package testutils
    20  
    21  import "google.golang.org/grpc/xds/internal/xdsclient/xdsresource"
    22  
    23  // TestResourceWatcher implements the xdsresource.ResourceWatcher interface,
    24  // used to receive updates on watches registered with the xDS client, when using
    25  // the resource-type agnostic WatchResource API.
    26  //
    27  // Tests can use the channels provided by this type to get access to updates and
    28  // errors sent by the xDS client.
    29  type TestResourceWatcher struct {
    30  	// UpdateCh is the channel on which xDS client updates are delivered.
    31  	UpdateCh chan *xdsresource.ResourceData
    32  	// AmbientErrorCh is the channel on which ambient errors from the xDS
    33  	// client are delivered.
    34  	AmbientErrorCh chan error
    35  	// ResourceErrorCh is the channel on which resource errors from the xDS
    36  	// client are delivered.
    37  	ResourceErrorCh chan struct{}
    38  }
    39  
    40  // ResourceChanged is invoked by the xDS client to report the latest update.
    41  func (w *TestResourceWatcher) ResourceChanged(data xdsresource.ResourceData, onDone func()) {
    42  	defer onDone()
    43  	select {
    44  	case <-w.UpdateCh:
    45  	default:
    46  	}
    47  	w.UpdateCh <- &data
    48  
    49  }
    50  
    51  // ResourceError is invoked by the xDS client to report the latest error to
    52  // stop watching the resource.
    53  func (w *TestResourceWatcher) ResourceError(err error, onDone func()) {
    54  	defer onDone()
    55  	select {
    56  	case <-w.ResourceErrorCh:
    57  	case <-w.AmbientErrorCh:
    58  	default:
    59  	}
    60  	w.AmbientErrorCh <- err
    61  	w.ResourceErrorCh <- struct{}{}
    62  }
    63  
    64  // AmbientError is invoked by the xDS client to report the latest ambient
    65  // error.
    66  func (w *TestResourceWatcher) AmbientError(err error, onDone func()) {
    67  	defer onDone()
    68  	select {
    69  	case <-w.AmbientErrorCh:
    70  	default:
    71  	}
    72  	w.AmbientErrorCh <- err
    73  }
    74  
    75  // NewTestResourceWatcher returns a TestResourceWatcher to watch for resources
    76  // via the xDS client.
    77  func NewTestResourceWatcher() *TestResourceWatcher {
    78  	return &TestResourceWatcher{
    79  		UpdateCh:        make(chan *xdsresource.ResourceData, 1),
    80  		AmbientErrorCh:  make(chan error, 1),
    81  		ResourceErrorCh: make(chan struct{}, 1),
    82  	}
    83  }