1 files changed, 193 insertions, 0 deletions
diff --git a/modules/queue/queue_disk_channel.go b/modules/queue/queue_disk_channel.go
new file mode 100644
index 0000000000..895c8ce918
--- /dev/null
+++ b/modules/queue/queue_disk_channel.go
@@ -0,0 +1,193 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package queue
+
+import (
+	"context"
+	"time"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+// PersistableChannelQueueType is the type for persistable queue
+const PersistableChannelQueueType Type = "persistable-channel"
+
+// PersistableChannelQueueConfiguration is the configuration for a PersistableChannelQueue
+type PersistableChannelQueueConfiguration struct {
+	Name         string
+	DataDir      string
+	BatchLength  int
+	QueueLength  int
+	Timeout      time.Duration
+	MaxAttempts  int
+	Workers      int
+	MaxWorkers   int
+	BlockTimeout time.Duration
+	BoostTimeout time.Duration
+	BoostWorkers int
+}
+
+// PersistableChannelQueue wraps a channel queue and level queue together
+type PersistableChannelQueue struct {
+	*ChannelQueue
+	delayedStarter
+	closed chan struct{}
+}
+
+// NewPersistableChannelQueue creates a wrapped batched channel queue with persistable level queue backend when shutting down
+// This differs from a wrapped queue in that the persistent queue is only used to persist at shutdown/terminate
+func NewPersistableChannelQueue(handle HandlerFunc, cfg, exemplar interface{}) (Queue, error) {
+	configInterface, err := toConfig(PersistableChannelQueueConfiguration{}, cfg)
+	if err != nil {
+		return nil, err
+	}
+	config := configInterface.(PersistableChannelQueueConfiguration)
+
+	channelQueue, err := NewChannelQueue(handle, ChannelQueueConfiguration{
+		QueueLength:  config.QueueLength,
+		BatchLength:  config.BatchLength,
+		Workers:      config.Workers,
+		MaxWorkers:   config.MaxWorkers,
+		BlockTimeout: config.BlockTimeout,
+		BoostTimeout: config.BoostTimeout,
+		BoostWorkers: config.BoostWorkers,
+		Name:         config.Name + "-channel",
+	}, exemplar)
+	if err != nil {
+		return nil, err
+	}
+
+	// the level backend only needs temporary workers to catch up with the previously dropped work
+	levelCfg := LevelQueueConfiguration{
+		DataDir:      config.DataDir,
+		QueueLength:  config.QueueLength,
+		BatchLength:  config.BatchLength,
+		Workers:      1,
+		MaxWorkers:   6,
+		BlockTimeout: 1 * time.Second,
+		BoostTimeout: 5 * time.Minute,
+		BoostWorkers: 5,
+		Name:         config.Name + "-level",
+	}
+
+	levelQueue, err := NewLevelQueue(handle, levelCfg, exemplar)
+	if err == nil {
+		queue := &PersistableChannelQueue{
+			ChannelQueue: channelQueue.(*ChannelQueue),
+			delayedStarter: delayedStarter{
+				internal: levelQueue.(*LevelQueue),
+				name:     config.Name,
+			},
+			closed: make(chan struct{}),
+		}
+		_ = GetManager().Add(queue, PersistableChannelQueueType, config, exemplar, nil)
+		return queue, nil
+	}
+	if IsErrInvalidConfiguration(err) {
+		// Retrying ain't gonna make this any better...
+		return nil, ErrInvalidConfiguration{cfg: cfg}
+	}
+
+	queue := &PersistableChannelQueue{
+		ChannelQueue: channelQueue.(*ChannelQueue),
+		delayedStarter: delayedStarter{
+			cfg:         levelCfg,
+			underlying:  LevelQueueType,
+			timeout:     config.Timeout,
+			maxAttempts: config.MaxAttempts,
+			name:        config.Name,
+		},
+		closed: make(chan struct{}),
+	}
+	_ = GetManager().Add(queue, PersistableChannelQueueType, config, exemplar, nil)
+	return queue, nil
+}
+
+// Name returns the name of this queue
+func (p *PersistableChannelQueue) Name() string {
+	return p.delayedStarter.name
+}
+
+// Push will push the indexer data to queue
+func (p *PersistableChannelQueue) Push(data Data) error {
+	select {
+	case <-p.closed:
+		return p.internal.Push(data)
+	default:
+		return p.ChannelQueue.Push(data)
+	}
+}
+
+// Run starts to run the queue
+func (p *PersistableChannelQueue) Run(atShutdown, atTerminate func(context.Context, func())) {
+	p.lock.Lock()
+	if p.internal == nil {
+		err := p.setInternal(atShutdown, p.ChannelQueue.pool.handle, p.exemplar)
+		p.lock.Unlock()
+		if err != nil {
+			log.Fatal("Unable to create internal queue for %s Error: %v", p.Name(), err)
+			return
+		}
+	} else {
+		p.lock.Unlock()
+	}
+	atShutdown(context.Background(), p.Shutdown)
+	atTerminate(context.Background(), p.Terminate)
+
+	// Just run the level queue - we shut it down later
+	go p.internal.Run(func(_ context.Context, _ func()) {}, func(_ context.Context, _ func()) {})
+
+	go func() {
+		_ = p.ChannelQueue.pool.AddWorkers(p.workers, 0)
+	}()
+
+	log.Trace("PersistableChannelQueue: %s Waiting til closed", p.delayedStarter.name)
+	<-p.closed
+	log.Trace("PersistableChannelQueue: %s Cancelling pools", p.delayedStarter.name)
+	p.ChannelQueue.pool.cancel()
+	p.internal.(*LevelQueue).pool.cancel()
+	log.Trace("PersistableChannelQueue: %s Waiting til done", p.delayedStarter.name)
+	p.ChannelQueue.pool.Wait()
+	p.internal.(*LevelQueue).pool.Wait()
+	// Redirect all remaining data in the chan to the internal channel
+	go func() {
+		log.Trace("PersistableChannelQueue: %s Redirecting remaining data", p.delayedStarter.name)
+		for data := range p.ChannelQueue.pool.dataChan {
+			_ = p.internal.Push(data)
+		}
+		log.Trace("PersistableChannelQueue: %s Done Redirecting remaining data", p.delayedStarter.name)
+	}()
+	log.Trace("PersistableChannelQueue: %s Done main loop", p.delayedStarter.name)
+}
+
+// Shutdown processing this queue
+func (p *PersistableChannelQueue) Shutdown() {
+	log.Trace("PersistableChannelQueue: %s Shutdown", p.delayedStarter.name)
+	select {
+	case <-p.closed:
+	default:
+		p.lock.Lock()
+		defer p.lock.Unlock()
+		if p.internal != nil {
+			p.internal.(*LevelQueue).Shutdown()
+		}
+		close(p.closed)
+	}
+}
+
+// Terminate this queue and close the queue
+func (p *PersistableChannelQueue) Terminate() {
+	log.Trace("PersistableChannelQueue: %s Terminating", p.delayedStarter.name)
+	p.Shutdown()
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	if p.internal != nil {
+		p.internal.(*LevelQueue).Terminate()
+	}
+}
+
+func init() {
+	queuesMap[PersistableChannelQueueType] = NewPersistableChannelQueue
+}