| // Copyright 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 xds |
| |
| import ( |
| "sync" |
| ) |
| |
| import ( |
| "github.com/apache/dubbo-go-pixiu/pilot/pkg/model" |
| ) |
| |
| type PushQueue struct { |
| cond *sync.Cond |
| |
| // pending stores all connections in the queue. If the same connection is enqueued again, |
| // the PushRequest will be merged. |
| pending map[*Connection]*model.PushRequest |
| |
| // queue maintains ordering of the queue |
| queue []*Connection |
| |
| // processing stores all connections that have been Dequeue(), but not MarkDone(). |
| // The value stored will be initially be nil, but may be populated if the connection is Enqueue(). |
| // If model.PushRequest is not nil, it will be Enqueued again once MarkDone has been called. |
| processing map[*Connection]*model.PushRequest |
| |
| shuttingDown bool |
| } |
| |
| func NewPushQueue() *PushQueue { |
| return &PushQueue{ |
| pending: make(map[*Connection]*model.PushRequest), |
| processing: make(map[*Connection]*model.PushRequest), |
| cond: sync.NewCond(&sync.Mutex{}), |
| } |
| } |
| |
| // Enqueue will mark a proxy as pending a push. If it is already pending, pushInfo will be merged. |
| // ServiceEntry updates will be added together, and full will be set if either were full |
| func (p *PushQueue) Enqueue(con *Connection, pushRequest *model.PushRequest) { |
| p.cond.L.Lock() |
| defer p.cond.L.Unlock() |
| |
| if p.shuttingDown { |
| return |
| } |
| |
| // If its already in progress, merge the info and return |
| if request, f := p.processing[con]; f { |
| p.processing[con] = request.CopyMerge(pushRequest) |
| return |
| } |
| |
| if request, f := p.pending[con]; f { |
| p.pending[con] = request.CopyMerge(pushRequest) |
| return |
| } |
| |
| p.pending[con] = pushRequest |
| p.queue = append(p.queue, con) |
| // Signal waiters on Dequeue that a new item is available |
| p.cond.Signal() |
| } |
| |
| // Remove a proxy from the queue. If there are no proxies ready to be removed, this will block |
| func (p *PushQueue) Dequeue() (con *Connection, request *model.PushRequest, shutdown bool) { |
| p.cond.L.Lock() |
| defer p.cond.L.Unlock() |
| |
| // Block until there is one to remove. Enqueue will signal when one is added. |
| for len(p.queue) == 0 && !p.shuttingDown { |
| p.cond.Wait() |
| } |
| |
| if len(p.queue) == 0 { |
| // We must be shutting down. |
| return nil, nil, true |
| } |
| |
| con = p.queue[0] |
| // The underlying array will still exist, despite the slice changing, so the object may not GC without this |
| // See https://github.com/grpc/grpc-go/issues/4758 |
| p.queue[0] = nil |
| p.queue = p.queue[1:] |
| |
| request = p.pending[con] |
| delete(p.pending, con) |
| |
| // Mark the connection as in progress |
| p.processing[con] = nil |
| |
| return con, request, false |
| } |
| |
| func (p *PushQueue) MarkDone(con *Connection) { |
| p.cond.L.Lock() |
| defer p.cond.L.Unlock() |
| request := p.processing[con] |
| delete(p.processing, con) |
| |
| // If the info is present, that means Enqueue was called while connection was not yet marked done. |
| // This means we need to add it back to the queue. |
| if request != nil { |
| p.pending[con] = request |
| p.queue = append(p.queue, con) |
| p.cond.Signal() |
| } |
| } |
| |
| // Get number of pending proxies |
| func (p *PushQueue) Pending() int { |
| p.cond.L.Lock() |
| defer p.cond.L.Unlock() |
| return len(p.queue) |
| } |
| |
| // ShutDown will cause queue to ignore all new items added to it. As soon as the |
| // worker goroutines have drained the existing items in the queue, they will be |
| // instructed to exit. |
| func (p *PushQueue) ShutDown() { |
| p.cond.L.Lock() |
| defer p.cond.L.Unlock() |
| p.shuttingDown = true |
| p.cond.Broadcast() |
| } |