mirror of
https://github.com/optim-enterprises-bv/kubernetes.git
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292 lines
9.3 KiB
Go
292 lines
9.3 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package config
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import (
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"fmt"
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"sync"
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"time"
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"github.com/davecgh/go-spew/spew"
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"github.com/golang/glog"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/fields"
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"k8s.io/apimachinery/pkg/labels"
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"k8s.io/apimachinery/pkg/types"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/client-go/tools/cache"
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"k8s.io/kubernetes/pkg/api"
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listers "k8s.io/kubernetes/pkg/client/listers/core/internalversion"
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"k8s.io/kubernetes/pkg/util/config"
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)
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// Operation is a type of operation of services or endpoints.
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type Operation int
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// These are the available operation types.
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const (
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ADD Operation = iota
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UPDATE
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REMOVE
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SYNCED
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)
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// ServiceUpdate describes an operation of services, sent on the channel.
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// You can add, update or remove single service by setting Op == ADD|UPDATE|REMOVE.
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type ServiceUpdate struct {
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Service *api.Service
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Op Operation
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}
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// EndpointsUpdate describes an operation of endpoints, sent on the channel.
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// You can add, update or remove single endpoints by setting Op == ADD|UPDATE|REMOVE.
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type EndpointsUpdate struct {
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Endpoints *api.Endpoints
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Op Operation
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}
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// ServiceConfigHandler is an abstract interface of objects which receive update notifications for the set of services.
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type ServiceConfigHandler interface {
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// OnServiceUpdate gets called when a configuration has been changed by one of the sources.
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// This is the union of all the configuration sources.
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OnServiceUpdate(services []api.Service)
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}
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// EndpointsConfigHandler is an abstract interface of objects which receive update notifications for the set of endpoints.
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type EndpointsConfigHandler interface {
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// OnEndpointsUpdate gets called when endpoints configuration is changed for a given
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// service on any of the configuration sources. An example is when a new
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// service comes up, or when containers come up or down for an existing service.
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//
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// NOTE: For efficiency, endpoints are being passed by reference, thus,
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// OnEndpointsUpdate should NOT modify pointers of a given slice.
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// Those endpoints objects are shared with other layers of the system and
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// are guaranteed to be immutable with the assumption that are also
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// not mutated by those handlers. Make a deep copy if you need to modify
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// them in your code.
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OnEndpointsUpdate(endpoints []*api.Endpoints)
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}
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// EndpointsConfig tracks a set of endpoints configurations.
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// It accepts "set", "add" and "remove" operations of endpoints via channels, and invokes registered handlers on change.
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type EndpointsConfig struct {
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informer cache.Controller
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lister listers.EndpointsLister
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handlers []EndpointsConfigHandler
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// updates channel is used to trigger registered handlers.
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updates chan struct{}
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}
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// NewEndpointsConfig creates a new EndpointsConfig.
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func NewEndpointsConfig(c cache.Getter, period time.Duration) *EndpointsConfig {
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endpointsLW := cache.NewListWatchFromClient(c, "endpoints", metav1.NamespaceAll, fields.Everything())
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return newEndpointsConfig(endpointsLW, period)
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}
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func newEndpointsConfig(lw cache.ListerWatcher, period time.Duration) *EndpointsConfig {
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result := &EndpointsConfig{}
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store, informer := cache.NewIndexerInformer(
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lw,
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&api.Endpoints{},
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period,
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cache.ResourceEventHandlerFuncs{
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AddFunc: result.handleAddEndpoints,
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UpdateFunc: result.handleUpdateEndpoints,
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DeleteFunc: result.handleDeleteEndpoints,
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},
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cache.Indexers{},
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)
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result.informer = informer
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result.lister = listers.NewEndpointsLister(store)
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return result
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}
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// RegisterHandler registers a handler which is called on every endpoints change.
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func (c *EndpointsConfig) RegisterHandler(handler EndpointsConfigHandler) {
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c.handlers = append(c.handlers, handler)
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}
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func (c *EndpointsConfig) Run(stopCh <-chan struct{}) {
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// The updates channel is used to send interrupts to the Endpoints handler.
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// It's buffered because we never want to block for as long as there is a
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// pending interrupt, but don't want to drop them if the handler is doing
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// work.
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c.updates = make(chan struct{}, 1)
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go c.informer.Run(stopCh)
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if !cache.WaitForCacheSync(stopCh, c.informer.HasSynced) {
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utilruntime.HandleError(fmt.Errorf("endpoint controller not synced"))
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return
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}
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// We have synced informers. Now we can start delivering updates
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// to the registered handler.
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go func() {
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for range c.updates {
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endpoints, err := c.lister.List(labels.Everything())
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if err != nil {
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glog.Errorf("Error while listing endpoints from cache: %v", err)
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// This will cause a retry (if there isn't any other trigger in-flight).
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c.dispatchUpdate()
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continue
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}
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if endpoints == nil {
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endpoints = []*api.Endpoints{}
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}
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for i := range c.handlers {
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glog.V(3).Infof("Calling handler.OnEndpointsUpdate()")
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c.handlers[i].OnEndpointsUpdate(endpoints)
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}
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}
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}()
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// Close updates channel when stopCh is closed.
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go func() {
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<-stopCh
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close(c.updates)
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}()
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}
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func (c *EndpointsConfig) handleAddEndpoints(_ interface{}) {
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c.dispatchUpdate()
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}
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func (c *EndpointsConfig) handleUpdateEndpoints(_, _ interface{}) {
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c.dispatchUpdate()
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}
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func (c *EndpointsConfig) handleDeleteEndpoints(_ interface{}) {
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c.dispatchUpdate()
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}
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func (c *EndpointsConfig) dispatchUpdate() {
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select {
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case c.updates <- struct{}{}:
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default:
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glog.V(4).Infof("Endpoints handler already has a pending interrupt.")
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}
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}
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// ServiceConfig tracks a set of service configurations.
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// It accepts "set", "add" and "remove" operations of services via channels, and invokes registered handlers on change.
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type ServiceConfig struct {
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mux *config.Mux
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bcaster *config.Broadcaster
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store *serviceStore
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}
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// NewServiceConfig creates a new ServiceConfig.
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// It immediately runs the created ServiceConfig.
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func NewServiceConfig() *ServiceConfig {
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// The updates channel is used to send interrupts to the Services handler.
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// It's buffered because we never want to block for as long as there is a
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// pending interrupt, but don't want to drop them if the handler is doing
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// work.
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updates := make(chan struct{}, 1)
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store := &serviceStore{updates: updates, services: make(map[string]map[types.NamespacedName]*api.Service)}
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mux := config.NewMux(store)
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bcaster := config.NewBroadcaster()
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go watchForUpdates(bcaster, store, updates)
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return &ServiceConfig{mux, bcaster, store}
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}
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// RegisterHandler registers a handler which is called on every services change.
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func (c *ServiceConfig) RegisterHandler(handler ServiceConfigHandler) {
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c.bcaster.Add(config.ListenerFunc(func(instance interface{}) {
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glog.V(3).Infof("Calling handler.OnServiceUpdate()")
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handler.OnServiceUpdate(instance.([]api.Service))
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}))
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}
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// Channel returns a channel to which services updates should be delivered.
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func (c *ServiceConfig) Channel(source string) chan ServiceUpdate {
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ch := c.mux.Channel(source)
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serviceCh := make(chan ServiceUpdate)
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go func() {
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for update := range serviceCh {
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ch <- update
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}
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}()
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return serviceCh
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}
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// Config returns list of all services from underlying store.
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func (c *ServiceConfig) Config() []api.Service {
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return c.store.MergedState().([]api.Service)
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}
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type serviceStore struct {
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serviceLock sync.RWMutex
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services map[string]map[types.NamespacedName]*api.Service
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synced bool
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updates chan<- struct{}
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}
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func (s *serviceStore) Merge(source string, change interface{}) error {
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s.serviceLock.Lock()
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services := s.services[source]
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if services == nil {
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services = make(map[types.NamespacedName]*api.Service)
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}
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update := change.(ServiceUpdate)
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switch update.Op {
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case ADD, UPDATE:
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glog.V(5).Infof("Adding new service from source %s : %s", source, spew.Sdump(update.Service))
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name := types.NamespacedName{Namespace: update.Service.Namespace, Name: update.Service.Name}
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services[name] = update.Service
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case REMOVE:
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glog.V(5).Infof("Removing a service %s", spew.Sdump(update.Service))
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name := types.NamespacedName{Namespace: update.Service.Namespace, Name: update.Service.Name}
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delete(services, name)
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case SYNCED:
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s.synced = true
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default:
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glog.V(4).Infof("Received invalid update type: %s", spew.Sdump(update))
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}
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s.services[source] = services
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synced := s.synced
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s.serviceLock.Unlock()
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if s.updates != nil && synced {
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select {
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case s.updates <- struct{}{}:
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default:
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glog.V(4).Infof("Service handler already has a pending interrupt.")
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}
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}
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return nil
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}
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func (s *serviceStore) MergedState() interface{} {
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s.serviceLock.RLock()
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defer s.serviceLock.RUnlock()
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services := make([]api.Service, 0)
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for _, sourceServices := range s.services {
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for _, value := range sourceServices {
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services = append(services, *value)
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}
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}
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return services
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}
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// watchForUpdates invokes bcaster.Notify() with the latest version of an object
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// when changes occur.
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func watchForUpdates(bcaster *config.Broadcaster, accessor config.Accessor, updates <-chan struct{}) {
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for true {
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<-updates
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bcaster.Notify(accessor.MergedState())
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}
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}
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