github.com/m3db/m3@v1.5.0/src/dbnode/topology/static.go (about)

     1  // Copyright (c) 2016 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 topology
    22  
    23  import (
    24  	"errors"
    25  
    26  	xwatch "github.com/m3db/m3/src/x/watch"
    27  )
    28  
    29  var (
    30  	errUnownedShard = errors.New("unowned shard")
    31  )
    32  
    33  type staticInitializer struct {
    34  	opts StaticOptions
    35  }
    36  
    37  // NewStaticInitializer creates a static topology initializer.
    38  func NewStaticInitializer(opts StaticOptions) Initializer {
    39  	return staticInitializer{opts}
    40  }
    41  
    42  func (i staticInitializer) Init() (Topology, error) {
    43  	if err := i.opts.Validate(); err != nil {
    44  		return nil, err
    45  	}
    46  	return NewStaticTopology(i.opts), nil
    47  }
    48  
    49  func (i staticInitializer) TopologyIsSet() (bool, error) {
    50  	// Always has the specified static topology ready.
    51  	return true, nil
    52  }
    53  
    54  type staticTopology struct {
    55  	w xwatch.Watchable
    56  }
    57  
    58  // NewStaticTopology creates a static topology.
    59  func NewStaticTopology(opts StaticOptions) Topology {
    60  	w := xwatch.NewWatchable()
    61  	w.Update(NewStaticMap(opts))
    62  	return &staticTopology{w: w}
    63  }
    64  
    65  func (t *staticTopology) Get() Map {
    66  	return t.w.Get().(Map)
    67  }
    68  
    69  func (t *staticTopology) Watch() (MapWatch, error) {
    70  	// Topology is static, the returned watch will not receive any updates.
    71  	_, w, err := t.w.Watch()
    72  	if err != nil {
    73  		return nil, err
    74  	}
    75  	return NewMapWatch(w), nil
    76  }
    77  
    78  func (t *staticTopology) Close() {}