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gitea/modules/queue/queue_bytefifo.go

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// Copyright 2020 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"
"fmt"
"sync"
"time"
"code.gitea.io/gitea/modules/json"
"code.gitea.io/gitea/modules/log"
)
// ByteFIFOQueueConfiguration is the configuration for a ByteFIFOQueue
type ByteFIFOQueueConfiguration struct {
WorkerPoolConfiguration
Workers int
Name string
WaitOnEmpty bool
}
var _ Queue = &ByteFIFOQueue{}
// ByteFIFOQueue is a Queue formed from a ByteFIFO and WorkerPool
type ByteFIFOQueue struct {
*WorkerPool
byteFIFO ByteFIFO
typ Type
shutdownCtx context.Context
shutdownCtxCancel context.CancelFunc
terminateCtx context.Context
terminateCtxCancel context.CancelFunc
exemplar interface{}
workers int
name string
lock sync.Mutex
waitOnEmpty bool
pushed chan struct{}
}
// NewByteFIFOQueue creates a new ByteFIFOQueue
func NewByteFIFOQueue(typ Type, byteFIFO ByteFIFO, handle HandlerFunc, cfg, exemplar interface{}) (*ByteFIFOQueue, error) {
configInterface, err := toConfig(ByteFIFOQueueConfiguration{}, cfg)
if err != nil {
return nil, err
}
config := configInterface.(ByteFIFOQueueConfiguration)
terminateCtx, terminateCtxCancel := context.WithCancel(context.Background())
shutdownCtx, shutdownCtxCancel := context.WithCancel(terminateCtx)
return &ByteFIFOQueue{
WorkerPool: NewWorkerPool(handle, config.WorkerPoolConfiguration),
byteFIFO: byteFIFO,
typ: typ,
shutdownCtx: shutdownCtx,
shutdownCtxCancel: shutdownCtxCancel,
terminateCtx: terminateCtx,
terminateCtxCancel: terminateCtxCancel,
exemplar: exemplar,
workers: config.Workers,
name: config.Name,
waitOnEmpty: config.WaitOnEmpty,
pushed: make(chan struct{}, 1),
}, nil
}
// Name returns the name of this queue
func (q *ByteFIFOQueue) Name() string {
return q.name
}
// Push pushes data to the fifo
func (q *ByteFIFOQueue) Push(data Data) error {
return q.PushFunc(data, nil)
}
// PushFunc pushes data to the fifo
func (q *ByteFIFOQueue) PushFunc(data Data, fn func() error) error {
if !assignableTo(data, q.exemplar) {
return fmt.Errorf("Unable to assign data: %v to same type as exemplar: %v in %s", data, q.exemplar, q.name)
}
bs, err := json.Marshal(data)
if err != nil {
return err
}
if q.waitOnEmpty {
defer func() {
select {
case q.pushed <- struct{}{}:
default:
}
}()
}
return q.byteFIFO.PushFunc(q.terminateCtx, bs, fn)
}
// IsEmpty checks if the queue is empty
func (q *ByteFIFOQueue) IsEmpty() bool {
q.lock.Lock()
defer q.lock.Unlock()
if !q.WorkerPool.IsEmpty() {
return false
}
return q.byteFIFO.Len(q.terminateCtx) == 0
}
// Run runs the bytefifo queue
func (q *ByteFIFOQueue) Run(atShutdown, atTerminate func(func())) {
atShutdown(q.Shutdown)
atTerminate(q.Terminate)
log.Debug("%s: %s Starting", q.typ, q.name)
_ = q.AddWorkers(q.workers, 0)
log.Trace("%s: %s Now running", q.typ, q.name)
q.readToChan()
<-q.shutdownCtx.Done()
log.Trace("%s: %s Waiting til done", q.typ, q.name)
q.Wait()
log.Trace("%s: %s Waiting til cleaned", q.typ, q.name)
q.CleanUp(q.terminateCtx)
q.terminateCtxCancel()
}
const maxBackOffTime = time.Second * 3
func (q *ByteFIFOQueue) readToChan() {
// handle quick cancels
select {
case <-q.shutdownCtx.Done():
// tell the pool to shutdown.
q.baseCtxCancel()
return
default:
}
// Default backoff values
backOffTime := time.Millisecond * 100
loop:
for {
err := q.doPop()
if err == errQueueEmpty {
log.Trace("%s: %s Waiting on Empty", q.typ, q.name)
select {
case <-q.pushed:
// reset backOffTime
backOffTime = 100 * time.Millisecond
continue loop
case <-q.shutdownCtx.Done():
// Oops we've been shutdown whilst waiting
// Make sure the worker pool is shutdown too
q.baseCtxCancel()
return
}
}
// Reset the backOffTime if there is no error or an unmarshalError
if err == nil || err == errUnmarshal {
backOffTime = 100 * time.Millisecond
}
if err != nil {
// Need to Backoff
select {
case <-q.shutdownCtx.Done():
// Oops we've been shutdown whilst backing off
// Make sure the worker pool is shutdown too
q.baseCtxCancel()
return
case <-time.After(backOffTime):
// OK we've waited - so backoff a bit
backOffTime += backOffTime / 2
if backOffTime > maxBackOffTime {
backOffTime = maxBackOffTime
}
continue loop
}
}
select {
case <-q.shutdownCtx.Done():
// Oops we've been shutdown
// Make sure the worker pool is shutdown too
q.baseCtxCancel()
return
default:
continue loop
}
}
}
var errQueueEmpty = fmt.Errorf("empty queue")
var errEmptyBytes = fmt.Errorf("empty bytes")
var errUnmarshal = fmt.Errorf("failed to unmarshal")
func (q *ByteFIFOQueue) doPop() error {
q.lock.Lock()
defer q.lock.Unlock()
bs, err := q.byteFIFO.Pop(q.shutdownCtx)
if err != nil {
if err == context.Canceled {
q.baseCtxCancel()
return err
}
log.Error("%s: %s Error on Pop: %v", q.typ, q.name, err)
return err
}
if len(bs) == 0 {
if q.waitOnEmpty && q.byteFIFO.Len(q.shutdownCtx) == 0 {
return errQueueEmpty
}
return errEmptyBytes
}
data, err := unmarshalAs(bs, q.exemplar)
if err != nil {
log.Error("%s: %s Failed to unmarshal with error: %v", q.typ, q.name, err)
return errUnmarshal
}
log.Trace("%s %s: Task found: %#v", q.typ, q.name, data)
q.WorkerPool.Push(data)
return nil
}
// Shutdown processing from this queue
func (q *ByteFIFOQueue) Shutdown() {
log.Trace("%s: %s Shutting down", q.typ, q.name)
select {
case <-q.shutdownCtx.Done():
return
default:
}
q.shutdownCtxCancel()
log.Debug("%s: %s Shutdown", q.typ, q.name)
}
// IsShutdown returns a channel which is closed when this Queue is shutdown
func (q *ByteFIFOQueue) IsShutdown() <-chan struct{} {
return q.shutdownCtx.Done()
}
// Terminate this queue and close the queue
func (q *ByteFIFOQueue) Terminate() {
log.Trace("%s: %s Terminating", q.typ, q.name)
q.Shutdown()
select {
case <-q.terminateCtx.Done():
return
default:
}
if log.IsDebug() {
log.Debug("%s: %s Closing with %d tasks left in queue", q.typ, q.name, q.byteFIFO.Len(q.terminateCtx))
}
q.terminateCtxCancel()
if err := q.byteFIFO.Close(); err != nil {
log.Error("Error whilst closing internal byte fifo in %s: %s: %v", q.typ, q.name, err)
}
log.Debug("%s: %s Terminated", q.typ, q.name)
}
// IsTerminated returns a channel which is closed when this Queue is terminated
func (q *ByteFIFOQueue) IsTerminated() <-chan struct{} {
return q.terminateCtx.Done()
}
var _ UniqueQueue = &ByteFIFOUniqueQueue{}
// ByteFIFOUniqueQueue represents a UniqueQueue formed from a UniqueByteFifo
type ByteFIFOUniqueQueue struct {
ByteFIFOQueue
}
// NewByteFIFOUniqueQueue creates a new ByteFIFOUniqueQueue
func NewByteFIFOUniqueQueue(typ Type, byteFIFO UniqueByteFIFO, handle HandlerFunc, cfg, exemplar interface{}) (*ByteFIFOUniqueQueue, error) {
configInterface, err := toConfig(ByteFIFOQueueConfiguration{}, cfg)
if err != nil {
return nil, err
}
config := configInterface.(ByteFIFOQueueConfiguration)
terminateCtx, terminateCtxCancel := context.WithCancel(context.Background())
shutdownCtx, shutdownCtxCancel := context.WithCancel(terminateCtx)
return &ByteFIFOUniqueQueue{
ByteFIFOQueue: ByteFIFOQueue{
WorkerPool: NewWorkerPool(handle, config.WorkerPoolConfiguration),
byteFIFO: byteFIFO,
typ: typ,
shutdownCtx: shutdownCtx,
shutdownCtxCancel: shutdownCtxCancel,
terminateCtx: terminateCtx,
terminateCtxCancel: terminateCtxCancel,
exemplar: exemplar,
workers: config.Workers,
name: config.Name,
},
}, nil
}
// Has checks if the provided data is in the queue
func (q *ByteFIFOUniqueQueue) Has(data Data) (bool, error) {
if !assignableTo(data, q.exemplar) {
return false, fmt.Errorf("Unable to assign data: %v to same type as exemplar: %v in %s", data, q.exemplar, q.name)
}
bs, err := json.Marshal(data)
if err != nil {
return false, err
}
return q.byteFIFO.(UniqueByteFIFO).Has(q.terminateCtx, bs)
}