feat: add bounded task priority and fair application dispatch

internal/transport/httpserver/worker.go

@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	"git.yuntuo.hk/k2safe/orbit/internal/dispatch"
 	"git.yuntuo.hk/k2safe/orbit/internal/fault"
 	"git.yuntuo.hk/k2safe/orbit/internal/jsonvalue"
 	"git.yuntuo.hk/k2safe/orbit/internal/jsonwire"
@@ -25,19 +26,25 @@ const WorkerSubprotocol = "pulse.worker.v1"
 
 // WorkerHub 管理节点内连接生命周期；任务归属和容量仍由 MySQL 决定。
 type WorkerHub struct {
-	service *worker.Service
-	ctx     context.Context
-	cancel  context.CancelFunc
-	slots   chan struct{}
-	mu      sync.Mutex
-	closing bool
-	wg      sync.WaitGroup
-	poll    time.Duration
+	service    *worker.Service
+	ctx        context.Context
+	cancel     context.CancelFunc
+	slots      chan struct{}
+	mu         sync.Mutex
+	closing    bool
+	wg         sync.WaitGroup
+	poll       time.Duration
+	dispatch   *dispatch.Pool
+	emptyPolls map[[32]byte]time.Time
 }
 
 func NewWorkerHub(parent context.Context, service *worker.Service) *WorkerHub {
 	ctx, cancel := context.WithCancel(parent)
-	return &WorkerHub{service: service, ctx: ctx, cancel: cancel, slots: make(chan struct{}, 128), poll: time.Second}
+	h := &WorkerHub{service: service, ctx: ctx, cancel: cancel, slots: make(chan struct{}, 128), poll: time.Second, emptyPolls: make(map[[32]byte]time.Time)}
+	h.dispatch = dispatch.New(ctx, 4, 128)
+	h.wg.Add(1)
+	go func() { defer h.wg.Done(); <-h.dispatch.Done() }()
+	return h
 }
 func RegisterWorkers(server *http.Server, hub *WorkerHub) {
 	server.Handler.(*http.ServeMux).Handle("GET /v1/worker/connect", hub)
@@ -249,12 +256,53 @@ func (h *WorkerHub) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	eligible := false
 	leases := map[core.ID]time.Time{}
 	cancelSent := map[core.ID]bool{}
+	results := make(chan claimResult, 1)
+	pending, burstLeft := false, 0
+	pollKey := workerPollKey(token.NamespaceID, input)
+	canRequest := func() bool {
+		return eligible && !draining && capacity > 0 && len(leases) < int(capacity) && len(outgoing) < 4
+	}
+	requestClaim := func() {
+		if pending || burstLeft == 0 || !canRequest() {
+			return
+		}
+		pending = h.dispatch.Submit(dispatch.Job{Context: ctx, Application: string(binding.ApplicationID), Queue: string(token.NamespaceID) + "/" + string(input.QueueID), Run: func(jobCtx context.Context) {
+			results <- h.claimFair(jobCtx, token, binding, pollKey)
+		}})
+		if pending {
+			burstLeft--
+		}
+	}
 	ticker := time.NewTicker(h.poll)
 	defer ticker.Stop()
 	for {
 		select {
 		case <-ctx.Done():
 			return
+		case result := <-results:
+			pending = false
+			if result.err != nil {
+				if fault.Code(result.err) == "STALE_SESSION" || fault.Code(result.err) == "UNAUTHENTICATED" || fault.Code(result.err) == "PERMISSION_DENIED" {
+					send(workerFrame{Type: "error", Error: publicWorkerError(result.err)}, true)
+					return
+				}
+				burstLeft = 0
+				continue
+			}
+			if result.assignment == nil {
+				burstLeft = 0
+				continue
+			}
+			assignment := result.assignment
+			raw, err := jsonwire.Marshal(assignment)
+			if err != nil {
+				return
+			}
+			leases[assignment.AttemptID] = assignment.LeaseUntil
+			if !send(workerFrame{Type: "task.assign", Body: raw}, false) {
+				return
+			}
+			requestClaim()
 		case frame := <-incoming:
 			call, stop := context.WithTimeout(ctx, 8*time.Second)
 			var body any
@@ -370,31 +418,9 @@ func (h *WorkerHub) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 					delete(leases, attempt)
 				}
 			}
-			if !eligible || draining || capacity == 0 || len(leases) >= int(capacity) || len(outgoing) >= 4 {
-				continue
-			}
-			for burst := 0; burst < 4 && len(leases) < int(capacity) && len(outgoing) < 4; burst++ {
-				call, stop := context.WithTimeout(ctx, 8*time.Second)
-				assignment, err := h.service.Claim(call, token, binding)
-				stop()
-				if err != nil {
-					if fault.Code(err) == "STALE_SESSION" || fault.Code(err) == "UNAUTHENTICATED" || fault.Code(err) == "PERMISSION_DENIED" {
-						send(workerFrame{Type: "error", Error: publicWorkerError(err)}, true)
-						return
-					}
-					break
-				}
-				if assignment == nil {
-					break
-				}
-				raw, err := jsonwire.Marshal(assignment)
-				if err != nil {
-					return
-				}
-				leases[assignment.AttemptID] = assignment.LeaseUntil
-				if !send(workerFrame{Type: "task.assign", Body: raw}, false) {
-					return
-				}
+			if !pending {
+				burstLeft = 4
+				requestClaim()
 			}
 		}
 	}