| 1 | package jobs |
| 2 | |
| 3 | import "sync" |
| 4 | |
| 5 | // RuntimeState counts operational work, including cancelled processes which |
| 6 | // have not exited. Revisions order updates from concurrent jobs in a manager. |
| 7 | type RuntimeState struct { |
| 8 | SessionID string |
| 9 | JobID string |
| 10 | Revision uint64 |
| 11 | Running int |
| 12 | } |
| 13 | |
| 14 | type runtimeObservers struct { |
| 15 | mu sync.Mutex |
| 16 | revision uint64 |
| 17 | next uint64 |
| 18 | listeners map[uint64]*runtimeSubscription |
| 19 | } |
| 20 | |
| 21 | type runtimeSubscription struct { |
| 22 | mu sync.Mutex |
| 23 | session string |
| 24 | callback func(RuntimeState) |
| 25 | pending *RuntimeState |
| 26 | draining bool |
| 27 | closed bool |
| 28 | } |
| 29 | |
| 30 | func (s *runtimeSubscription) enqueue(state RuntimeState) { |
| 31 | s.mu.Lock() |
| 32 | if s.closed { |
| 33 | s.mu.Unlock() |
| 34 | return |
| 35 | } |
| 36 | s.pending = &state |
| 37 | if s.draining { |
| 38 | s.mu.Unlock() |
| 39 | return |
| 40 | } |
| 41 | s.draining = true |
| 42 | s.mu.Unlock() |
| 43 | go func() { |
| 44 | for { |
| 45 | s.mu.Lock() |
| 46 | if s.closed || s.pending == nil { |
| 47 | s.draining = false |
| 48 | s.mu.Unlock() |
| 49 | return |
| 50 | } |
| 51 | state := *s.pending |
| 52 | s.pending = nil |
| 53 | s.mu.Unlock() |
| 54 | s.callback(state) |
| 55 | } |
| 56 | }() |
| 57 | } |
| 58 | |
| 59 | // SubscribeRuntime registers before reading, so a completion cannot disappear |
| 60 | // in the subscribe/read gap. Callbacks run off-lock with one pending snapshot. |
| 61 | func (m *Manager) SubscribeRuntime(session string, callback func(RuntimeState)) (RuntimeState, func()) { |
| 62 | m.runtimeObservers.mu.Lock() |
| 63 | defer m.runtimeObservers.mu.Unlock() |
| 64 | m.runtimeObservers.next++ |
| 65 | id := m.runtimeObservers.next |
| 66 | if m.runtimeObservers.listeners == nil { |
| 67 | m.runtimeObservers.listeners = map[uint64]*runtimeSubscription{} |
| 68 | } |
| 69 | sub := &runtimeSubscription{session: session, callback: callback} |
| 70 | m.runtimeObservers.listeners[id] = sub |
| 71 | initial := RuntimeState{SessionID: session, Revision: m.runtimeObservers.revision, Running: len(m.RunningForSession(session))} |
| 72 | return initial, func() { |
| 73 | m.runtimeObservers.mu.Lock() |
| 74 | delete(m.runtimeObservers.listeners, id) |
| 75 | m.runtimeObservers.mu.Unlock() |
| 76 | sub.mu.Lock() |
| 77 | sub.closed = true |
| 78 | sub.pending = nil |
| 79 | sub.mu.Unlock() |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | // notifyRuntime runs only after committing a start or closing done. Notices |
| 84 | // still precede done to protect DrainCompletedNote; they are not state signals. |
| 85 | func (m *Manager) notifyRuntime(session, jobID string) { |
| 86 | m.runtimeObservers.mu.Lock() |
| 87 | defer m.runtimeObservers.mu.Unlock() |
| 88 | m.runtimeObservers.revision++ |
| 89 | for _, sub := range m.runtimeObservers.listeners { |
| 90 | if sub.session != "" && session != "" && sub.session != session { |
| 91 | continue |
| 92 | } |
| 93 | sub.enqueue(RuntimeState{SessionID: sub.session, JobID: jobID, Revision: m.runtimeObservers.revision, Running: len(m.RunningForSession(sub.session))}) |
| 94 | } |
| 95 | } |
| 96 |