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woodpecker/cncd/queue/fifo.go
2020-05-18 16:41:15 +01:00

384 lines
8.3 KiB
Go

package queue
import (
"container/list"
"context"
"log"
"runtime"
"sync"
"time"
"github.com/sirupsen/logrus"
)
const (
StatusSkipped = "skipped"
StatusSuccess = "success"
StatusFailure = "failure"
)
type entry struct {
item *Task
done chan bool
retry int
error error
deadline time.Time
}
type worker struct {
filter Filter
channel chan *Task
}
type fifo struct {
sync.Mutex
workers map[*worker]struct{}
running map[string]*entry
pending *list.List
waitingOnDeps *list.List
extension time.Duration
paused bool
}
// New returns a new fifo queue.
func New() Queue {
return &fifo{
workers: map[*worker]struct{}{},
running: map[string]*entry{},
pending: list.New(),
waitingOnDeps: list.New(),
extension: time.Minute * 10,
paused: false,
}
}
// Push pushes an item to the tail of this queue.
func (q *fifo) Push(c context.Context, task *Task) error {
q.Lock()
q.pending.PushBack(task)
q.Unlock()
go q.process()
return nil
}
// Push pushes an item to the tail of this queue.
func (q *fifo) PushAtOnce(c context.Context, tasks []*Task) error {
q.Lock()
for _, task := range tasks {
q.pending.PushBack(task)
}
q.Unlock()
go q.process()
return nil
}
// Poll retrieves and removes the head of this queue.
func (q *fifo) Poll(c context.Context, f Filter) (*Task, error) {
q.Lock()
w := &worker{
channel: make(chan *Task, 1),
filter: f,
}
q.workers[w] = struct{}{}
q.Unlock()
go q.process()
for {
select {
case <-c.Done():
q.Lock()
delete(q.workers, w)
q.Unlock()
return nil, nil
case t := <-w.channel:
return t, nil
}
}
}
// Done signals that the item is done executing.
func (q *fifo) Done(c context.Context, id string, exitStatus string) error {
return q.finished([]string{id}, exitStatus, nil)
}
// Error signals that the item is done executing with error.
func (q *fifo) Error(c context.Context, id string, err error) error {
return q.finished([]string{id}, StatusFailure, err)
}
// Error signals that the item is done executing with error.
func (q *fifo) ErrorAtOnce(c context.Context, id []string, err error) error {
return q.finished(id, StatusFailure, err)
}
func (q *fifo) finished(ids []string, exitStatus string, err error) error {
q.Lock()
for _, id := range ids {
taskEntry, ok := q.running[id]
if ok {
taskEntry.error = err
close(taskEntry.done)
delete(q.running, id)
} else {
q.removeFromPending(id)
}
q.updateDepStatusInQueue(id, exitStatus)
}
q.Unlock()
return nil
}
// Evict removes a pending task from the queue.
func (q *fifo) Evict(c context.Context, id string) error {
return q.EvictAtOnce(c, []string{id})
}
// Evict removes a pending task from the queue.
func (q *fifo) EvictAtOnce(c context.Context, ids []string) error {
q.Lock()
defer q.Unlock()
for _, id := range ids {
var next *list.Element
for e := q.pending.Front(); e != nil; e = next {
next = e.Next()
task, ok := e.Value.(*Task)
if ok && task.ID == id {
q.pending.Remove(e)
return nil
}
}
}
return ErrNotFound
}
// Wait waits until the item is done executing.
func (q *fifo) Wait(c context.Context, id string) error {
q.Lock()
state := q.running[id]
q.Unlock()
if state != nil {
select {
case <-c.Done():
case <-state.done:
return state.error
}
}
return nil
}
// Extend extends the task execution deadline.
func (q *fifo) Extend(c context.Context, id string) error {
q.Lock()
defer q.Unlock()
state, ok := q.running[id]
if ok {
state.deadline = time.Now().Add(q.extension)
return nil
}
return ErrNotFound
}
// Info returns internal queue information.
func (q *fifo) Info(c context.Context) InfoT {
q.Lock()
stats := InfoT{}
stats.Stats.Workers = len(q.workers)
stats.Stats.Pending = q.pending.Len()
stats.Stats.WaitingOnDeps = q.waitingOnDeps.Len()
stats.Stats.Running = len(q.running)
for e := q.pending.Front(); e != nil; e = e.Next() {
stats.Pending = append(stats.Pending, e.Value.(*Task))
}
for e := q.waitingOnDeps.Front(); e != nil; e = e.Next() {
stats.WaitingOnDeps = append(stats.WaitingOnDeps, e.Value.(*Task))
}
for _, entry := range q.running {
stats.Running = append(stats.Running, entry.item)
}
stats.Paused = q.paused
q.Unlock()
return stats
}
func (q *fifo) Pause() {
q.Lock()
q.paused = true
q.Unlock()
}
func (q *fifo) Resume() {
q.Lock()
q.paused = false
q.Unlock()
go q.process()
}
// helper function that loops through the queue and attempts to
// match the item to a single subscriber.
func (q *fifo) process() {
q.Lock()
defer q.Unlock()
if q.paused {
return
}
defer func() {
// the risk of panic is low. This code can probably be removed
// once the code has been used in real world installs without issue.
if err := recover(); err != nil {
const size = 64 << 10
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
log.Printf("queue: unexpected panic: %v\n%s", err, buf)
}
}()
q.resubmitExpiredBuilds()
q.filterWaiting()
for pending, worker := q.assignToWorker(); pending != nil && worker != nil; pending, worker = q.assignToWorker() {
task := pending.Value.(*Task)
delete(q.workers, worker)
q.pending.Remove(pending)
q.running[task.ID] = &entry{
item: task,
done: make(chan bool),
deadline: time.Now().Add(q.extension),
}
worker.channel <- task
}
}
func (q *fifo) filterWaiting() {
// resubmits all waiting tasks to pending, deps may have cleared
var nextWaiting *list.Element
for e := q.waitingOnDeps.Front(); e != nil; e = nextWaiting {
nextWaiting = e.Next()
task := e.Value.(*Task)
q.pending.PushBack(task)
}
// rebuild waitingDeps
q.waitingOnDeps = list.New()
filtered := []*list.Element{}
var nextPending *list.Element
for e := q.pending.Front(); e != nil; e = nextPending {
nextPending = e.Next()
task := e.Value.(*Task)
if q.depsInQueue(task) {
logrus.Debugf("queue: waiting due to unmet dependencies %v", task.ID)
q.waitingOnDeps.PushBack(task)
filtered = append(filtered, e)
}
}
// filter waiting tasks
for _, f := range filtered {
q.pending.Remove(f)
}
}
func (q *fifo) assignToWorker() (*list.Element, *worker) {
var next *list.Element
for e := q.pending.Front(); e != nil; e = next {
next = e.Next()
task := e.Value.(*Task)
logrus.Debugf("queue: trying to assign task: %v with deps %v", task.ID, task.Dependencies)
for w := range q.workers {
if w.filter(task) {
logrus.Debugf("queue: assigned task: %v with deps %v", task.ID, task.Dependencies)
return e, w
}
}
}
return nil, nil
}
func (q *fifo) resubmitExpiredBuilds() {
for id, state := range q.running {
if time.Now().After(state.deadline) {
q.pending.PushFront(state.item)
delete(q.running, id)
close(state.done)
}
}
}
func (q *fifo) depsInQueue(task *Task) bool {
var next *list.Element
for e := q.pending.Front(); e != nil; e = next {
next = e.Next()
possibleDep, ok := e.Value.(*Task)
logrus.Debugf("queue: pending right now: %v", possibleDep.ID)
for _, dep := range task.Dependencies {
if ok && possibleDep.ID == dep {
return true
}
}
}
for possibleDepID := range q.running {
logrus.Debugf("queue: running right now: %v", possibleDepID)
for _, dep := range task.Dependencies {
if possibleDepID == dep {
return true
}
}
}
return false
}
func (q *fifo) updateDepStatusInQueue(taskID string, status string) {
var next *list.Element
for e := q.pending.Front(); e != nil; e = next {
next = e.Next()
pending, ok := e.Value.(*Task)
for _, dep := range pending.Dependencies {
if ok && taskID == dep {
pending.DepStatus[dep] = status
}
}
}
for _, running := range q.running {
for _, dep := range running.item.Dependencies {
if taskID == dep {
running.item.DepStatus[dep] = status
}
}
}
var n *list.Element
for e := q.waitingOnDeps.Front(); e != nil; e = n {
next = e.Next()
waiting, ok := e.Value.(*Task)
for _, dep := range waiting.Dependencies {
if ok && taskID == dep {
waiting.DepStatus[dep] = status
}
}
}
}
func (q *fifo) removeFromPending(taskID string) {
logrus.Debugf("queue: trying to remove %s", taskID)
var next *list.Element
for e := q.pending.Front(); e != nil; e = next {
next = e.Next()
task := e.Value.(*Task)
if task.ID == taskID {
logrus.Debugf("queue: %s is removed from pending", taskID)
q.pending.Remove(e)
return
}
}
}