1 files changed, 107 insertions, 0 deletions
diff --git a/worker_watcher/container/channel/vec.go b/worker_watcher/container/channel/vec.go
new file mode 100644
index 00000000..fd50c8d1
--- /dev/null
+++ b/worker_watcher/container/channel/vec.go
@@ -0,0 +1,107 @@
+package channel
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+
+	"github.com/spiral/errors"
+	"github.com/spiral/roadrunner/v2/worker"
+)
+
+type Vec struct {
+	sync.RWMutex
+	// destroy signal
+	destroy uint64
+	// channel with the workers
+	workers chan worker.BaseProcess
+}
+
+func NewVector(len uint64) *Vec {
+	vec := &Vec{
+		destroy: 0,
+		workers: make(chan worker.BaseProcess, len),
+	}
+
+	return vec
+}
+
+// Push is O(1) operation
+// In case of TTL and full channel O(n) worst case, where n is len of the channel
+func (v *Vec) Push(w worker.BaseProcess) {
+	// Non-blocking channel send
+	select {
+	case v.workers <- w:
+		// default select branch is only possible when dealing with TTL
+		// because in that case, workers in the v.workers channel can be TTL-ed and killed
+		// but presenting in the channel
+	default:
+		// Stop Pop operations
+		v.Lock()
+		defer v.Unlock()
+
+		/*
+			we can be in the default branch by the following reasons:
+			1. TTL is set with no requests during the TTL
+			2. Violated Get <-> Release operation (how ??)
+		*/
+		for i := 0; i < len(v.workers); i++ {
+			/*
+				We need to drain vector until we found a worker in the Invalid/Killing/Killed/etc states.
+			*/
+			wrk := <-v.workers
+			switch wrk.State().Value() {
+			// skip good states, put worker back
+			case worker.StateWorking, worker.StateReady:
+				// put the worker back
+				// generally, while send and receive operations are concurrent (from the channel), channel behave
+				// like a FIFO, but when re-sending from the same goroutine it behaves like a FILO
+				v.workers <- wrk
+				continue
+				/*
+					Bad states are here.
+				*/
+			default:
+				// kill the current worker (just to be sure it's dead)
+				if wrk != nil {
+					_ = wrk.Kill()
+				}
+				// replace with the new one and return from the loop
+				// new worker can be ttl-ed at this moment, it's possible to replace TTL-ed worker with new TTL-ed worker
+				// But this case will be handled in the worker_watcher::Get
+				v.workers <- w
+				return
+			}
+		}
+	}
+}
+
+func (v *Vec) Remove(_ int64) {}
+
+func (v *Vec) Pop(ctx context.Context) (worker.BaseProcess, error) {
+	/*
+		if *addr == old {
+			*addr = new
+			return true
+		}
+	*/
+
+	if atomic.LoadUint64(&v.destroy) == 1 {
+		return nil, errors.E(errors.WatcherStopped)
+	}
+
+	// used only for the TTL-ed workers
+	v.RLock()
+	defer v.RUnlock()
+
+	select {
+	case w := <-v.workers:
+		return w, nil
+	case <-ctx.Done():
+		return nil, errors.E(ctx.Err(), errors.NoFreeWorkers)
+	}
+}
+
+func (v *Vec) Destroy() {
+	atomic.StoreUint64(&v.destroy, 1)
+}