81 lines
1.6 KiB
Go
81 lines
1.6 KiB
Go
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// Copyright 2019 Drone.IO Inc. All rights reserved.
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// Use of this source code is governed by the Drone Non-Commercial License
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// that can be found in the LICENSE file.
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package queue
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import (
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"context"
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"sync"
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"time"
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)
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type canceller struct {
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sync.Mutex
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subscribers map[chan struct{}]int64
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cancelled map[int64]time.Time
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}
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func newCanceller() *canceller {
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return &canceller{
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subscribers: make(map[chan struct{}]int64),
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cancelled: make(map[int64]time.Time),
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}
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}
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func (c *canceller) Cancel(ctx context.Context, id int64) error {
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c.Lock()
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c.cancelled[id] = time.Now().Add(time.Minute * 5)
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for subscriber, build := range c.subscribers {
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if id == build {
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close(subscriber)
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}
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}
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c.collect()
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c.Unlock()
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return nil
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}
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func (c *canceller) Cancelled(ctx context.Context, id int64) (bool, error) {
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subscriber := make(chan struct{})
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c.Lock()
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c.subscribers[subscriber] = id
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c.Unlock()
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defer func() {
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c.Lock()
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delete(c.subscribers, subscriber)
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c.Unlock()
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}()
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for {
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select {
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case <-ctx.Done():
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return false, ctx.Err()
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case <-time.After(time.Minute):
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c.Lock()
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_, ok := c.cancelled[id]
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c.Unlock()
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if ok {
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return true, nil
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}
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case <-subscriber:
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return true, nil
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}
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}
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}
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func (c *canceller) collect() {
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// the list of cancelled builds is stored with a ttl, and
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// is not removed until the ttl is reached. This provides
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// adequate window for clients with connectivity issues to
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// reconnect and receive notification of cancel events.
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now := time.Now()
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for build, timestamp := range c.cancelled {
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if now.After(timestamp) {
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delete(c.cancelled, build)
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}
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}
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}
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