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/*
*
* Copyright 2020 gRPC 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 xdsclient
import (
"context"
"fmt"
"sync"
"google.golang.org/grpc/xds/internal/xdsclient/xdsresource"
)
// This is only required temporarily, while we modify the
// clientImpl.WatchListener API to be implemented via the wrapper
// WatchListener() API which calls the WatchResource() API.
type listenerWatcher struct {
resourceName string
cb func(xdsresource.ListenerUpdate, error)
}
func (l *listenerWatcher) OnUpdate(update *xdsresource.ListenerResourceData) {
l.cb(update.Resource, nil)
}
func (l *listenerWatcher) OnError(err error) {
l.cb(xdsresource.ListenerUpdate{}, err)
}
func (l *listenerWatcher) OnResourceDoesNotExist() {
err := xdsresource.NewErrorf(xdsresource.ErrorTypeResourceNotFound, "resource name %q of type Listener not found in received response", l.resourceName)
l.cb(xdsresource.ListenerUpdate{}, err)
}
// WatchListener uses LDS to discover information about the Listener resource
// identified by resourceName.
func (c *clientImpl) WatchListener(resourceName string, cb func(xdsresource.ListenerUpdate, error)) (cancel func()) {
watcher := &listenerWatcher{resourceName: resourceName, cb: cb}
return xdsresource.WatchListener(c, resourceName, watcher)
}
// This is only required temporarily, while we modify the
// clientImpl.WatchRouteConfig API to be implemented via the wrapper
// WatchRouteConfig() API which calls the WatchResource() API.
type routeConfigWatcher struct {
resourceName string
cb func(xdsresource.RouteConfigUpdate, error)
}
func (r *routeConfigWatcher) OnUpdate(update *xdsresource.RouteConfigResourceData) {
r.cb(update.Resource, nil)
}
func (r *routeConfigWatcher) OnError(err error) {
r.cb(xdsresource.RouteConfigUpdate{}, err)
}
func (r *routeConfigWatcher) OnResourceDoesNotExist() {
err := xdsresource.NewErrorf(xdsresource.ErrorTypeResourceNotFound, "resource name %q of type RouteConfiguration not found in received response", r.resourceName)
r.cb(xdsresource.RouteConfigUpdate{}, err)
}
// WatchRouteConfig uses RDS to discover information about the
// RouteConfiguration resource identified by resourceName.
func (c *clientImpl) WatchRouteConfig(resourceName string, cb func(xdsresource.RouteConfigUpdate, error)) (cancel func()) {
watcher := &routeConfigWatcher{resourceName: resourceName, cb: cb}
return xdsresource.WatchRouteConfig(c, resourceName, watcher)
}
// This is only required temporarily, while we modify the
// clientImpl.WatchCluster API to be implemented via the wrapper WatchCluster()
// API which calls the WatchResource() API.
type clusterWatcher struct {
resourceName string
cb func(xdsresource.ClusterUpdate, error)
}
func (c *clusterWatcher) OnUpdate(update *xdsresource.ClusterResourceData) {
c.cb(update.Resource, nil)
}
func (c *clusterWatcher) OnError(err error) {
c.cb(xdsresource.ClusterUpdate{}, err)
}
func (c *clusterWatcher) OnResourceDoesNotExist() {
err := xdsresource.NewErrorf(xdsresource.ErrorTypeResourceNotFound, "resource name %q of type Cluster not found in received response", c.resourceName)
c.cb(xdsresource.ClusterUpdate{}, err)
}
// WatchCluster uses CDS to discover information about the Cluster resource
// identified by resourceName.
//
// WatchCluster can be called multiple times, with same or different
// clusterNames. Each call will start an independent watcher for the resource.
func (c *clientImpl) WatchCluster(resourceName string, cb func(xdsresource.ClusterUpdate, error)) (cancel func()) {
watcher := &clusterWatcher{resourceName: resourceName, cb: cb}
return xdsresource.WatchCluster(c, resourceName, watcher)
}
// This is only required temporarily, while we modify the
// clientImpl.WatchEndpoints API to be implemented via the wrapper
// WatchEndpoints() API which calls the WatchResource() API.
type endpointsWatcher struct {
resourceName string
cb func(xdsresource.EndpointsUpdate, error)
}
func (c *endpointsWatcher) OnUpdate(update *xdsresource.EndpointsResourceData) {
c.cb(update.Resource, nil)
}
func (c *endpointsWatcher) OnError(err error) {
c.cb(xdsresource.EndpointsUpdate{}, err)
}
func (c *endpointsWatcher) OnResourceDoesNotExist() {
err := xdsresource.NewErrorf(xdsresource.ErrorTypeResourceNotFound, "resource name %q of type Endpoints not found in received response", c.resourceName)
c.cb(xdsresource.EndpointsUpdate{}, err)
}
// WatchEndpoints uses EDS to discover information about the
// ClusterLoadAssignment resource identified by resourceName.
//
// WatchEndpoints can be called multiple times, with same or different
// clusterNames. Each call will start an independent watcher for the resource.
func (c *clientImpl) WatchEndpoints(resourceName string, cb func(xdsresource.EndpointsUpdate, error)) (cancel func()) {
watcher := &endpointsWatcher{resourceName: resourceName, cb: cb}
return xdsresource.WatchEndpoints(c, resourceName, watcher)
}
// WatchResource uses xDS to discover the resource associated with the provided
// resource name. The resource type implementation determines how xDS requests
// are sent out and how responses are deserialized and validated. Upon receipt
// of a response from the management server, an appropriate callback on the
// watcher is invoked.
func (c *clientImpl) WatchResource(rType xdsresource.Type, resourceName string, watcher xdsresource.ResourceWatcher) (cancel func()) {
// Return early if the client is already closed.
//
// The client returned from the top-level API is a ref-counted client which
// contains a pointer to `clientImpl`. When all references are released, the
// ref-counted client sets its pointer to `nil`. And if any watch APIs are
// made on such a closed client, we will get here with a `nil` receiver.
if c == nil || c.done.HasFired() {
logger.Warningf("Watch registered for name %q of type %q, but client is closed", rType.TypeName(), resourceName)
return func() {}
}
if err := c.resourceTypes.maybeRegister(rType); err != nil {
logger.Warningf("Watch registered for name %q of type %q which is already registered", rType.TypeName(), resourceName)
c.serializer.Schedule(func(context.Context) { watcher.OnError(err) })
return func() {}
}
// TODO: replace this with the code does the following when we have
// implemented generic watch API on the authority:
// - Parse the resource name and extract the authority.
// - Locate the corresponding authority object and acquire a reference to
// it. If the authority is not found, error out.
// - Call the watchResource() method on the authority.
// - Return a cancel function to cancel the watch on the authority and to
// release the reference.
// TODO: Make ParseName return an error if parsing fails, and
// schedule the OnError callback in that case.
n := xdsresource.ParseName(resourceName)
a, unref, err := c.findAuthority(n)
if err != nil {
logger.Warningf("Watch registered for name %q of type %q, authority %q is not found", rType.TypeName(), resourceName, n.Authority)
c.serializer.Schedule(func(context.Context) { watcher.OnError(err) })
return func() {}
}
cancelF := a.watchResource(rType, n.String(), watcher)
return func() {
cancelF()
unref()
}
}
// A registry of xdsresource.Type implementations indexed by their corresponding
// type URLs. Registration of an xdsresource.Type happens the first time a watch
// for a resource of that type is invoked.
type resourceTypeRegistry struct {
mu sync.Mutex
types map[string]xdsresource.Type
}
func newResourceTypeRegistry() *resourceTypeRegistry {
return &resourceTypeRegistry{types: make(map[string]xdsresource.Type)}
}
func (r *resourceTypeRegistry) get(url string) xdsresource.Type {
r.mu.Lock()
defer r.mu.Unlock()
return r.types[url]
}
func (r *resourceTypeRegistry) maybeRegister(rType xdsresource.Type) error {
r.mu.Lock()
defer r.mu.Unlock()
url := rType.TypeURL()
typ, ok := r.types[url]
if ok && typ != rType {
return fmt.Errorf("attempt to re-register a resource type implementation for %v", rType.TypeName())
}
r.types[url] = rType
return nil
}
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