Method acquireConnectionSlot

controlplane/session_mgr.go:195–271

(ctx context.Context, pid int32, username string, protocol string, profile *WorkerProfile)

		vcpus := 1
		if requestedVCPUs != nil {
			var err error
			vcpus, err = requestedVCPUs(profile)
			if err != nil {
				return nil, err
			}
		}
		if vcpus <= 0 {
			return nil, fmt.Errorf("requested vcpus must be positive, got %d", vcpus)
		}
		limits := func(user string) configstore.OrgResourceLimits {
			if resourceLimits == nil {
				return configstore.OrgResourceLimits{}
			}
			return resourceLimits(user)
		}
		lease, err := limiter.Acquire(ctx, connectionAdmissionRequest{
			PID:            pid,
			Username:       username,
			Protocol:       protocol,
			RequestedVCPUs: vcpus,
		}, limits)
		if err != nil {
			return nil, err
		}
		if sm.lifecycle.isClosed() {
			sm.releaseConnectionSlot(lease)
			return nil, ErrSessionManagerDraining
		}
		return lease, nil
	}

	sm.mu.Lock()
	if sm.lifecycle.isClosed() {
		sm.mu.Unlock()
		return nil, ErrSessionManagerDraining
	}
	if sm.maxConnections <= 0 || sm.activeSlots < sm.maxConnections {
		sm.activeSlots++
		sm.mu.Unlock()
		return nil, nil
	}
	waiter := &connectionWaiter{ready: make(chan struct{})}
	sm.waiters = append(sm.waiters, waiter)
	sm.mu.Unlock()

	select {
	case <-waiter.ready:
		if waiter.err != nil {
			return nil, waiter.err
		}
		return nil, nil
	case <-ctx.Done():
		sm.mu.Lock()
		defer sm.mu.Unlock()
		if waiter.granted {
			return nil, nil
		}
		sm.removeWaiterLocked(waiter)