实现预分配 RunnerService facade

internal/assignmentqueue/jetstream.go

@@ -52,6 +52,11 @@ type Accepter interface {
 	Accept(context.Context, taskassignment.Assignment) (bool, error)
 }
 
+type Claims interface {
+	Offer(taskassignment.Assignment) (<-chan struct{}, error)
+	WaitClaimed(context.Context, string) error
+}
+
 // Message is the subset of jetstream.Msg needed by one reconciliation.
 type Message interface {
 	Data() []byte
@@ -62,19 +67,24 @@ type Message interface {
 
 // Processor maps one delivery to one idempotent worker reconciliation.
 type Processor struct {
-	TrustDomain string
-	Accepter    Accepter
-	RetryDelay  time.Duration
+	TrustDomain  string
+	Accepter     Accepter
+	Claims       Claims
+	RetryDelay   time.Duration
+	ClaimTimeout time.Duration
 }
 
 func (p Processor) Process(ctx context.Context, message Message) error {
-	if p.Accepter == nil {
-		return errors.New("assignment accepter is required")
+	if p.Accepter == nil || p.Claims == nil {
+		return errors.New("assignment accepter and claim registry are required")
 	}
 	assignment, err := taskassignment.Unmarshal(message.Data(), p.TrustDomain)
 	if err != nil {
 		return errors.Join(err, message.TermWithReason("invalid assignment"))
 	}
+	if _, err := p.Claims.Offer(assignment); err != nil {
+		return errors.Join(err, message.TermWithReason("conflicting assignment"))
+	}
 	accepted, err := p.Accepter.Accept(ctx, assignment)
 	if err != nil {
 		delay := p.RetryDelay
@@ -84,6 +94,20 @@ func (p Processor) Process(ctx context.Context, message Message) error {
 		return errors.Join(err, message.NakWithDelay(delay))
 	}
 	if accepted {
+		timeout := p.ClaimTimeout
+		if timeout <= 0 {
+			timeout = 4 * time.Minute
+		}
+		claimContext, cancel := context.WithTimeout(ctx, timeout)
+		err := p.Claims.WaitClaimed(claimContext, assignment.ID)
+		cancel()
+		if err != nil {
+			delay := p.RetryDelay
+			if delay <= 0 {
+				delay = 2 * time.Second
+			}
+			return errors.Join(err, message.NakWithDelay(delay))
+		}
 		if err := message.DoubleAck(ctx); err != nil {
 			return fmt.Errorf("ack assignment %s: %w", assignment.ID, err)
 		}