mirror of
https://github.com/go-gitea/gitea.git
synced 2024-08-28 23:27:27 +02:00
332 lines
9.6 KiB
Go
332 lines
9.6 KiB
Go
|
// Copyright 2023 The Gitea Authors. All rights reserved.
|
||
|
// SPDX-License-Identifier: MIT
|
||
|
|
||
|
package queue
|
||
|
|
||
|
import (
|
||
|
"context"
|
||
|
"sync"
|
||
|
"sync/atomic"
|
||
|
"time"
|
||
|
|
||
|
"code.gitea.io/gitea/modules/log"
|
||
|
)
|
||
|
|
||
|
var (
|
||
|
infiniteTimerC = make(chan time.Time)
|
||
|
batchDebounceDuration = 100 * time.Millisecond
|
||
|
workerIdleDuration = 1 * time.Second
|
||
|
|
||
|
unhandledItemRequeueDuration atomic.Int64 // to avoid data race during test
|
||
|
)
|
||
|
|
||
|
func init() {
|
||
|
unhandledItemRequeueDuration.Store(int64(5 * time.Second))
|
||
|
}
|
||
|
|
||
|
// workerGroup is a group of workers to work with a WorkerPoolQueue
|
||
|
type workerGroup[T any] struct {
|
||
|
q *WorkerPoolQueue[T]
|
||
|
wg sync.WaitGroup
|
||
|
|
||
|
ctxWorker context.Context
|
||
|
ctxWorkerCancel context.CancelFunc
|
||
|
|
||
|
batchBuffer []T
|
||
|
popItemChan chan []byte
|
||
|
popItemErr chan error
|
||
|
}
|
||
|
|
||
|
func (wg *workerGroup[T]) doPrepareWorkerContext() {
|
||
|
wg.ctxWorker, wg.ctxWorkerCancel = context.WithCancel(wg.q.ctxRun)
|
||
|
}
|
||
|
|
||
|
// doDispatchBatchToWorker dispatches a batch of items to worker's channel.
|
||
|
// If the channel is full, it tries to start a new worker if possible.
|
||
|
func (q *WorkerPoolQueue[T]) doDispatchBatchToWorker(wg *workerGroup[T], flushChan chan flushType) {
|
||
|
batch := wg.batchBuffer
|
||
|
wg.batchBuffer = nil
|
||
|
|
||
|
if len(batch) == 0 {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
full := false
|
||
|
select {
|
||
|
case q.batchChan <- batch:
|
||
|
default:
|
||
|
full = true
|
||
|
}
|
||
|
|
||
|
q.workerNumMu.Lock()
|
||
|
noWorker := q.workerNum == 0
|
||
|
if full || noWorker {
|
||
|
if q.workerNum < q.workerMaxNum || noWorker && q.workerMaxNum <= 0 {
|
||
|
q.workerNum++
|
||
|
q.doStartNewWorker(wg)
|
||
|
}
|
||
|
}
|
||
|
q.workerNumMu.Unlock()
|
||
|
|
||
|
if full {
|
||
|
select {
|
||
|
case q.batchChan <- batch:
|
||
|
case flush := <-flushChan:
|
||
|
q.doWorkerHandle(batch)
|
||
|
q.doFlush(wg, flush)
|
||
|
case <-q.ctxRun.Done():
|
||
|
wg.batchBuffer = batch // return the batch to buffer, the "doRun" function will handle it
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// doWorkerHandle calls the safeHandler to handle a batch of items, and it increases/decreases the active worker number.
|
||
|
// If the context has been canceled, it should not be caller because the "Push" still needs the context, in such case, call q.safeHandler directly
|
||
|
func (q *WorkerPoolQueue[T]) doWorkerHandle(batch []T) {
|
||
|
q.workerNumMu.Lock()
|
||
|
q.workerActiveNum++
|
||
|
q.workerNumMu.Unlock()
|
||
|
|
||
|
defer func() {
|
||
|
q.workerNumMu.Lock()
|
||
|
q.workerActiveNum--
|
||
|
q.workerNumMu.Unlock()
|
||
|
}()
|
||
|
|
||
|
unhandled := q.safeHandler(batch...)
|
||
|
// if none of the items were handled, it should back-off for a few seconds
|
||
|
// in this case the handler (eg: document indexer) may have encountered some errors/failures
|
||
|
if len(unhandled) == len(batch) && unhandledItemRequeueDuration.Load() != 0 {
|
||
|
log.Error("Queue %q failed to handle batch of %d items, backoff for a few seconds", q.GetName(), len(batch))
|
||
|
select {
|
||
|
case <-q.ctxRun.Done():
|
||
|
case <-time.After(time.Duration(unhandledItemRequeueDuration.Load())):
|
||
|
}
|
||
|
}
|
||
|
for _, item := range unhandled {
|
||
|
if err := q.Push(item); err != nil {
|
||
|
if !q.basePushForShutdown(item) {
|
||
|
log.Error("Failed to requeue item for queue %q when calling handler: %v", q.GetName(), err)
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// basePushForShutdown tries to requeue items into the base queue when the WorkerPoolQueue is shutting down.
|
||
|
// If the queue is shutting down, it returns true and try to push the items
|
||
|
// Otherwise it does nothing and returns false
|
||
|
func (q *WorkerPoolQueue[T]) basePushForShutdown(items ...T) bool {
|
||
|
ctxShutdown := q.ctxShutdown.Load()
|
||
|
if ctxShutdown == nil {
|
||
|
return false
|
||
|
}
|
||
|
for _, item := range items {
|
||
|
// if there is still any error, the queue can do nothing instead of losing the items
|
||
|
if err := q.baseQueue.PushItem(*ctxShutdown, q.marshal(item)); err != nil {
|
||
|
log.Error("Failed to requeue item for queue %q when shutting down: %v", q.GetName(), err)
|
||
|
}
|
||
|
}
|
||
|
return true
|
||
|
}
|
||
|
|
||
|
// doStartNewWorker starts a new worker for the queue, the worker reads from worker's channel and handles the items.
|
||
|
func (q *WorkerPoolQueue[T]) doStartNewWorker(wp *workerGroup[T]) {
|
||
|
wp.wg.Add(1)
|
||
|
|
||
|
go func() {
|
||
|
defer wp.wg.Done()
|
||
|
|
||
|
log.Debug("Queue %q starts new worker", q.GetName())
|
||
|
defer log.Debug("Queue %q stops idle worker", q.GetName())
|
||
|
|
||
|
t := time.NewTicker(workerIdleDuration)
|
||
|
keepWorking := true
|
||
|
stopWorking := func() {
|
||
|
q.workerNumMu.Lock()
|
||
|
keepWorking = false
|
||
|
q.workerNum--
|
||
|
q.workerNumMu.Unlock()
|
||
|
}
|
||
|
for keepWorking {
|
||
|
select {
|
||
|
case <-wp.ctxWorker.Done():
|
||
|
stopWorking()
|
||
|
case batch, ok := <-q.batchChan:
|
||
|
if !ok {
|
||
|
stopWorking()
|
||
|
} else {
|
||
|
q.doWorkerHandle(batch)
|
||
|
t.Reset(workerIdleDuration)
|
||
|
}
|
||
|
case <-t.C:
|
||
|
q.workerNumMu.Lock()
|
||
|
keepWorking = q.workerNum <= 1
|
||
|
if !keepWorking {
|
||
|
q.workerNum--
|
||
|
}
|
||
|
q.workerNumMu.Unlock()
|
||
|
}
|
||
|
}
|
||
|
}()
|
||
|
}
|
||
|
|
||
|
// doFlush flushes the queue: it tries to read all items from the queue and handles them.
|
||
|
// It is for testing purpose only. It's not designed to work for a cluster.
|
||
|
func (q *WorkerPoolQueue[T]) doFlush(wg *workerGroup[T], flush flushType) {
|
||
|
log.Debug("Queue %q starts flushing", q.GetName())
|
||
|
defer log.Debug("Queue %q finishes flushing", q.GetName())
|
||
|
|
||
|
// stop all workers, and prepare a new worker context to start new workers
|
||
|
|
||
|
wg.ctxWorkerCancel()
|
||
|
wg.wg.Wait()
|
||
|
|
||
|
defer func() {
|
||
|
close(flush)
|
||
|
wg.doPrepareWorkerContext()
|
||
|
}()
|
||
|
|
||
|
// drain the batch channel first
|
||
|
loop:
|
||
|
for {
|
||
|
select {
|
||
|
case batch := <-q.batchChan:
|
||
|
q.doWorkerHandle(batch)
|
||
|
default:
|
||
|
break loop
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// drain the popItem channel
|
||
|
emptyCounter := 0
|
||
|
for {
|
||
|
select {
|
||
|
case data, dataOk := <-wg.popItemChan:
|
||
|
if !dataOk {
|
||
|
return
|
||
|
}
|
||
|
emptyCounter = 0
|
||
|
if v, jsonOk := q.unmarshal(data); !jsonOk {
|
||
|
continue
|
||
|
} else {
|
||
|
q.doWorkerHandle([]T{v})
|
||
|
}
|
||
|
case err := <-wg.popItemErr:
|
||
|
if !q.isCtxRunCanceled() {
|
||
|
log.Error("Failed to pop item from queue %q (doFlush): %v", q.GetName(), err)
|
||
|
}
|
||
|
return
|
||
|
case <-q.ctxRun.Done():
|
||
|
log.Debug("Queue %q is shutting down", q.GetName())
|
||
|
return
|
||
|
case <-time.After(20 * time.Millisecond):
|
||
|
// There is no reliable way to make sure all queue items are consumed by the Flush, there always might be some items stored in some buffers/temp variables.
|
||
|
// If we run Gitea in a cluster, we can even not guarantee all items are consumed in a deterministic instance.
|
||
|
// Luckily, the "Flush" trick is only used in tests, so far so good.
|
||
|
if cnt, _ := q.baseQueue.Len(q.ctxRun); cnt == 0 && len(wg.popItemChan) == 0 {
|
||
|
emptyCounter++
|
||
|
}
|
||
|
if emptyCounter >= 2 {
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func (q *WorkerPoolQueue[T]) isCtxRunCanceled() bool {
|
||
|
select {
|
||
|
case <-q.ctxRun.Done():
|
||
|
return true
|
||
|
default:
|
||
|
return false
|
||
|
}
|
||
|
}
|
||
|
|
||
|
var skipFlushChan = make(chan flushType) // an empty flush chan, used to skip reading other flush requests
|
||
|
|
||
|
// doRun is the main loop of the queue. All related "doXxx" functions are executed in its context.
|
||
|
func (q *WorkerPoolQueue[T]) doRun() {
|
||
|
log.Debug("Queue %q starts running", q.GetName())
|
||
|
defer log.Debug("Queue %q stops running", q.GetName())
|
||
|
|
||
|
wg := &workerGroup[T]{q: q}
|
||
|
wg.doPrepareWorkerContext()
|
||
|
wg.popItemChan, wg.popItemErr = popItemByChan(q.ctxRun, q.baseQueue.PopItem)
|
||
|
|
||
|
defer func() {
|
||
|
q.ctxRunCancel()
|
||
|
|
||
|
// drain all data on the fly
|
||
|
// since the queue is shutting down, the items can't be dispatched to workers because the context is canceled
|
||
|
// it can't call doWorkerHandle either, because there is no chance to push unhandled items back to the queue
|
||
|
var unhandled []T
|
||
|
close(q.batchChan)
|
||
|
for batch := range q.batchChan {
|
||
|
unhandled = append(unhandled, batch...)
|
||
|
}
|
||
|
unhandled = append(unhandled, wg.batchBuffer...)
|
||
|
for data := range wg.popItemChan {
|
||
|
if v, ok := q.unmarshal(data); ok {
|
||
|
unhandled = append(unhandled, v)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
ctxShutdownPtr := q.ctxShutdown.Load()
|
||
|
if ctxShutdownPtr != nil {
|
||
|
// if there is a shutdown context, try to push the items back to the base queue
|
||
|
q.basePushForShutdown(unhandled...)
|
||
|
workerDone := make(chan struct{})
|
||
|
// the only way to wait for the workers, because the handlers do not have context to wait for
|
||
|
go func() { wg.wg.Wait(); close(workerDone) }()
|
||
|
select {
|
||
|
case <-workerDone:
|
||
|
case <-(*ctxShutdownPtr).Done():
|
||
|
log.Error("Queue %q is shutting down, but workers are still running after timeout", q.GetName())
|
||
|
}
|
||
|
} else {
|
||
|
// if there is no shutdown context, just call the handler to try to handle the items. if the handler fails again, the items are lost
|
||
|
q.safeHandler(unhandled...)
|
||
|
}
|
||
|
|
||
|
close(q.shutdownDone)
|
||
|
}()
|
||
|
|
||
|
var batchDispatchC <-chan time.Time = infiniteTimerC
|
||
|
for {
|
||
|
select {
|
||
|
case data, dataOk := <-wg.popItemChan:
|
||
|
if !dataOk {
|
||
|
return
|
||
|
}
|
||
|
if v, jsonOk := q.unmarshal(data); !jsonOk {
|
||
|
testRecorder.Record("pop:corrupted:%s", data) // in rare cases the levelqueue(leveldb) might be corrupted
|
||
|
continue
|
||
|
} else {
|
||
|
wg.batchBuffer = append(wg.batchBuffer, v)
|
||
|
}
|
||
|
if len(wg.batchBuffer) >= q.batchLength {
|
||
|
q.doDispatchBatchToWorker(wg, q.flushChan)
|
||
|
} else if batchDispatchC == infiniteTimerC {
|
||
|
batchDispatchC = time.After(batchDebounceDuration)
|
||
|
} // else: batchDispatchC is already a debounce timer, it will be triggered soon
|
||
|
case <-batchDispatchC:
|
||
|
batchDispatchC = infiniteTimerC
|
||
|
q.doDispatchBatchToWorker(wg, q.flushChan)
|
||
|
case flush := <-q.flushChan:
|
||
|
// before flushing, it needs to try to dispatch the batch to worker first, in case there is no worker running
|
||
|
// after the flushing, there is at least one worker running, so "doFlush" could wait for workers to finish
|
||
|
// since we are already in a "flush" operation, so the dispatching function shouldn't read the flush chan.
|
||
|
q.doDispatchBatchToWorker(wg, skipFlushChan)
|
||
|
q.doFlush(wg, flush)
|
||
|
case err := <-wg.popItemErr:
|
||
|
if !q.isCtxRunCanceled() {
|
||
|
log.Error("Failed to pop item from queue %q (doRun): %v", q.GetName(), err)
|
||
|
}
|
||
|
return
|
||
|
case <-q.ctxRun.Done():
|
||
|
log.Debug("Queue %q is shutting down", q.GetName())
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
}
|