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package worker_watcher //nolint:golint,stylecheck
import (
"context"
"sync"
"github.com/spiral/errors"
"github.com/spiral/roadrunner/v2/internal"
"github.com/spiral/roadrunner/v2/pkg/events"
"github.com/spiral/roadrunner/v2/pkg/worker"
)
// workerCreateFunc can be nil, but in that case, dead stack will not be replaced
func NewSyncWorkerWatcher(allocator worker.Allocator, numWorkers int64, events events.Handler) Watcher {
ww := &workerWatcher{
stack: NewWorkersStack(uint64(numWorkers)),
allocator: allocator,
events: events,
}
return ww
}
type workerWatcher struct {
mutex sync.RWMutex
stack *Stack
allocator worker.Allocator
events events.Handler
}
func (ww *workerWatcher) AddToWatch(workers []worker.SyncWorker) error {
for i := 0; i < len(workers); i++ {
ww.stack.Push(workers[i])
go func(swc worker.SyncWorker) {
ww.wait(swc)
}(workers[i])
}
return nil
}
func (ww *workerWatcher) GetFreeWorker(ctx context.Context) (*worker.SyncWorkerImpl, error) {
const op = errors.Op("worker_watcher_get_free_worker")
// thread safe operation
w, stop := ww.stack.Pop()
if stop {
return nil, errors.E(op, errors.WatcherStopped)
}
// handle worker remove state
// in this state worker is destroyed by supervisor
if w != nil && w.State().Value() == internal.StateRemove {
err := ww.RemoveWorker(w)
if err != nil {
return nil, err
}
// try to get next
return ww.GetFreeWorker(ctx)
}
// no free stack
if w == nil {
for {
select {
default:
w, stop = ww.stack.Pop()
if stop {
return nil, errors.E(op, errors.WatcherStopped)
}
if w == nil {
continue
}
return w, nil
case <-ctx.Done():
return nil, errors.E(op, errors.NoFreeWorkers, errors.Str("no free workers in the stack, timeout exceed"))
}
}
}
return w, nil
}
func (ww *workerWatcher) AllocateNew() error {
ww.stack.mutex.Lock()
const op = errors.Op("worker_watcher_allocate_new")
sw, err := ww.allocator()
if err != nil {
return errors.E(op, errors.WorkerAllocate, err)
}
ww.addToWatch(sw)
ww.stack.mutex.Unlock()
ww.PushWorker(sw)
return nil
}
func (ww *workerWatcher) RemoveWorker(wb worker.SyncWorker) error {
ww.mutex.Lock()
defer ww.mutex.Unlock()
const op = errors.Op("worker_watcher_remove_worker")
pid := wb.Pid()
if ww.stack.FindAndRemoveByPid(pid) {
wb.State().Set(internal.StateRemove)
err := wb.Kill()
if err != nil {
return errors.E(op, err)
}
return nil
}
return nil
}
// O(1) operation
func (ww *workerWatcher) PushWorker(w worker.SyncWorker) {
ww.mutex.Lock()
defer ww.mutex.Unlock()
ww.stack.Push(w)
}
// Destroy all underlying stack (but let them to complete the task)
func (ww *workerWatcher) Destroy(ctx context.Context) {
// destroy stack, we don't use ww mutex here, since we should be able to push worker
ww.stack.Destroy(ctx)
}
// Warning, this is O(n) operation, and it will return copy of the actual workers
func (ww *workerWatcher) WorkersList() []*worker.SyncWorkerImpl {
return ww.stack.Workers()
}
func (ww *workerWatcher) wait(w worker.SyncWorker) {
const op = errors.Op("worker_watcher_wait")
err := w.Wait()
if err != nil {
ww.events.Push(events.WorkerEvent{
Event: events.EventWorkerError,
Worker: w,
Payload: errors.E(op, err),
})
}
if w.State().Value() == internal.StateDestroyed {
// worker was manually destroyed, no need to replace
ww.events.Push(events.PoolEvent{Event: events.EventWorkerDestruct, Payload: w})
return
}
_ = ww.stack.FindAndRemoveByPid(w.Pid())
err = ww.AllocateNew()
if err != nil {
ww.events.Push(events.PoolEvent{
Event: events.EventPoolError,
Payload: errors.E(op, err),
})
}
}
func (ww *workerWatcher) addToWatch(wb worker.SyncWorker) {
go func() {
ww.wait(wb)
}()
}
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