133 lines
4.3 KiB
Go
133 lines
4.3 KiB
Go
/*
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*
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* Copyright 2021 gRPC authors.
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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*/
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package server
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import (
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"sync"
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"google.golang.org/grpc/xds/internal/xdsclient/xdsresource"
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)
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// rdsHandlerUpdate wraps the full RouteConfigUpdate that are dynamically
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// queried for a given server side listener.
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type rdsHandlerUpdate struct {
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updates map[string]xdsresource.RouteConfigUpdate
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err error
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}
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// rdsHandler handles any RDS queries that need to be started for a given server
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// side listeners Filter Chains (i.e. not inline).
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type rdsHandler struct {
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xdsC XDSClient
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mu sync.Mutex
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updates map[string]xdsresource.RouteConfigUpdate
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cancels map[string]func()
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// For a rdsHandler update, the only update wrapped listener cares about is
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// most recent one, so this channel will be opportunistically drained before
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// sending any new updates.
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updateChannel chan rdsHandlerUpdate
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}
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// newRDSHandler creates a new rdsHandler to watch for RDS resources.
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// listenerWrapper updates the list of route names to watch by calling
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// updateRouteNamesToWatch() upon receipt of new Listener configuration.
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func newRDSHandler(xdsC XDSClient, ch chan rdsHandlerUpdate) *rdsHandler {
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return &rdsHandler{
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xdsC: xdsC,
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updateChannel: ch,
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updates: make(map[string]xdsresource.RouteConfigUpdate),
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cancels: make(map[string]func()),
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}
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}
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// updateRouteNamesToWatch handles a list of route names to watch for a given
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// server side listener (if a filter chain specifies dynamic RDS configuration).
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// This function handles all the logic with respect to any routes that may have
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// been added or deleted as compared to what was previously present.
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func (rh *rdsHandler) updateRouteNamesToWatch(routeNamesToWatch map[string]bool) {
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rh.mu.Lock()
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defer rh.mu.Unlock()
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// Add and start watches for any routes for any new routes in
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// routeNamesToWatch.
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for routeName := range routeNamesToWatch {
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if _, ok := rh.cancels[routeName]; !ok {
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func(routeName string) {
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rh.cancels[routeName] = rh.xdsC.WatchRouteConfig(routeName, func(update xdsresource.RouteConfigUpdate, err error) {
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rh.handleRouteUpdate(routeName, update, err)
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})
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}(routeName)
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}
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}
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// Delete and cancel watches for any routes from persisted routeNamesToWatch
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// that are no longer present.
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for routeName := range rh.cancels {
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if _, ok := routeNamesToWatch[routeName]; !ok {
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rh.cancels[routeName]()
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delete(rh.cancels, routeName)
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delete(rh.updates, routeName)
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}
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}
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// If the full list (determined by length) of updates are now successfully
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// updated, the listener is ready to be updated.
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if len(rh.updates) == len(rh.cancels) && len(routeNamesToWatch) != 0 {
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drainAndPush(rh.updateChannel, rdsHandlerUpdate{updates: rh.updates})
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}
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}
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// handleRouteUpdate persists the route config for a given route name, and also
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// sends an update to the Listener Wrapper on an error received or if the rds
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// handler has a full collection of updates.
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func (rh *rdsHandler) handleRouteUpdate(routeName string, update xdsresource.RouteConfigUpdate, err error) {
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if err != nil {
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drainAndPush(rh.updateChannel, rdsHandlerUpdate{err: err})
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return
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}
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rh.mu.Lock()
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defer rh.mu.Unlock()
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rh.updates[routeName] = update
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// If the full list (determined by length) of updates have successfully
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// updated, the listener is ready to be updated.
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if len(rh.updates) == len(rh.cancels) {
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drainAndPush(rh.updateChannel, rdsHandlerUpdate{updates: rh.updates})
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}
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}
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func drainAndPush(ch chan rdsHandlerUpdate, update rdsHandlerUpdate) {
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select {
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case <-ch:
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default:
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}
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ch <- update
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}
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// close() is meant to be called by wrapped listener when the wrapped listener
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// is closed, and it cleans up resources by canceling all the active RDS
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// watches.
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func (rh *rdsHandler) close() {
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rh.mu.Lock()
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defer rh.mu.Unlock()
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for _, cancel := range rh.cancels {
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cancel()
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}
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}
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