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options_manager.go
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/
options_manager.go
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// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package runtime
import (
"github.com/m3db/m3/src/x/close"
"github.com/m3db/m3/src/x/watch"
)
// OptionsManager manages runtime options.
type OptionsManager interface {
// SetRuntimeOptions sets the runtime options.
SetRuntimeOptions(value Options)
// RuntimeOptions returns the current runtime options.
RuntimeOptions() Options
// RegisterWatcher registers a watcher that watches updates to runtime options.
// When an update arrives, the manager will deliver the update to all registered
// watchers.
RegisterWatcher(l OptionsWatcher) close.SimpleCloser
// Close closes the watcher and all descendent watches
Close()
}
// OptionsWatcher watches for updates to runtime options.
type OptionsWatcher interface {
// SetRuntimeOptions is called for registerer watchers when the runtime options
// are updated, passing in the updated options as the argument.
SetRuntimeOptions(value Options)
}
type optionsManager struct {
watchable watch.Watchable
}
// NewOptionsManager creates a new runtime options manager.
func NewOptionsManager(initialValue Options) OptionsManager {
watchable := watch.NewWatchable()
watchable.Update(initialValue)
return &optionsManager{
watchable: watchable,
}
}
func (w *optionsManager) SetRuntimeOptions(value Options) {
w.watchable.Update(value)
}
func (w *optionsManager) RuntimeOptions() Options {
return w.watchable.Get().(Options)
}
func (w *optionsManager) RegisterWatcher(
watcher OptionsWatcher,
) close.SimpleCloser {
_, watch, _ := w.watchable.Watch()
// The watchable is always initialized so it's okay to do a blocking read.
<-watch.C()
// Deliver the current runtime options.
watcher.SetRuntimeOptions(watch.Get().(Options))
// Spawn a new goroutine that will terminate when the
// watchable terminates on the close of the runtime options manager.
go func() {
for range watch.C() {
watcher.SetRuntimeOptions(watch.Get().(Options))
}
}()
return watch
}
func (w *optionsManager) Close() {
w.watchable.Close()
}