github.com/m3db/m3@v1.5.0/src/cluster/services/watch.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package services
    22  
    23  import (
    24  	"github.com/m3db/m3/src/x/watch"
    25  )
    26  
    27  // NewWatch creates a Watch.
    28  func NewWatch(w watch.Watch) Watch {
    29  	return &serviceWatch{value: w}
    30  }
    31  
    32  type serviceWatch struct {
    33  	value watch.Watch
    34  }
    35  
    36  func (w *serviceWatch) Close() {
    37  	w.value.Close()
    38  }
    39  
    40  func (w *serviceWatch) C() <-chan struct{} {
    41  	return w.value.C()
    42  }
    43  
    44  func (w *serviceWatch) Get() Service {
    45  	return w.value.Get().(Service)
    46  }
    47  
    48  type serviceWatchable interface {
    49  	watches() int
    50  	update(v Service)
    51  	get() Service
    52  	watch() (Service, Watch, error)
    53  }
    54  
    55  type watchable struct {
    56  	value watch.Watchable
    57  }
    58  
    59  func newServiceWatchable() serviceWatchable {
    60  	return &watchable{value: watch.NewWatchable()}
    61  }
    62  
    63  func (w *watchable) watches() int {
    64  	return w.value.NumWatches()
    65  }
    66  
    67  func (w *watchable) update(v Service) {
    68  	w.value.Update(v)
    69  }
    70  
    71  func (w *watchable) get() Service {
    72  	return w.value.Get().(Service)
    73  }
    74  
    75  func (w *watchable) watch() (Service, Watch, error) {
    76  	curr, newWatch, err := w.value.Watch()
    77  	if err != nil {
    78  		return nil, nil, err
    79  	}
    80  	return curr.(Service), NewWatch(newWatch), nil
    81  }