/
monitor.go
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/
monitor.go
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// Copyright 2017 Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package memory
import (
"istio.io/istio/pilot/pkg/model"
"istio.io/istio/pkg/log"
)
const (
// BufferSize specifies the buffer size of event channel
BufferSize = 100
)
// Handler specifies a function to apply on a Config for a given event type
type Handler func(model.Config, model.Event)
// Monitor provides methods of manipulating changes in the config store
type Monitor interface {
Run(<-chan struct{})
AppendEventHandler(string, Handler)
ScheduleProcessEvent(ConfigEvent)
}
// ConfigEvent defines the event to be processed
type ConfigEvent struct {
config model.Config
event model.Event
}
type configstoreMonitor struct {
store model.ConfigStore
handlers map[string][]Handler
eventCh chan ConfigEvent
}
// NewMonitor returns new Monitor implementation with a default event buffer size.
func NewMonitor(store model.ConfigStore) Monitor {
return NewBufferedMonitor(store, BufferSize)
}
// NewBufferedMonitor returns new Monitor implementation with the specified event buffer size
func NewBufferedMonitor(store model.ConfigStore, bufferSize int) Monitor {
handlers := make(map[string][]Handler)
for _, typ := range store.ConfigDescriptor().Types() {
handlers[typ] = make([]Handler, 0)
}
return &configstoreMonitor{
store: store,
handlers: handlers,
eventCh: make(chan ConfigEvent, bufferSize),
}
}
func (m *configstoreMonitor) ScheduleProcessEvent(configEvent ConfigEvent) {
m.eventCh <- configEvent
}
func (m *configstoreMonitor) Run(stop <-chan struct{}) {
for {
select {
case <-stop:
if _, ok := <-m.eventCh; ok {
close(m.eventCh)
}
return
case ce, ok := <-m.eventCh:
if ok {
m.processConfigEvent(ce)
}
}
}
}
func (m *configstoreMonitor) processConfigEvent(ce ConfigEvent) {
if _, exists := m.handlers[ce.config.Type]; !exists {
log.Warnf("Config Type %s does not exist in config store", ce.config.Type)
return
}
m.applyHandlers(ce.config, ce.event)
}
func (m *configstoreMonitor) AppendEventHandler(typ string, h Handler) {
m.handlers[typ] = append(m.handlers[typ], h)
}
func (m *configstoreMonitor) applyHandlers(config model.Config, e model.Event) {
for _, f := range m.handlers[config.Type] {
f(config, e)
}
}