Esempio n. 1
0
// exportPtr returns *permPtrMsg if importer is nil, and *ptrMsg otherwise.
func (r *Runtime) exportPtr(v interface{}, importer circuit.Addr) interface{} {
	// Add exported value to export table
	exph := r.exp.Add(v, importer)

	if importer == nil {
		return &permPtrMsg{ID: exph.ID, TypeID: exph.Type.ID}
	}

	// Monitor the importer for liveness.
	// DropPtr the handles upon importer death.
	r.lk.Lock()
	defer r.lk.Unlock()
	_, ok := r.live[importer]
	if !ok {
		r.live[importer] = struct{}{}

		// The anonymous function creates a "lifeline" connection to the worker importing v.
		// When this conncetion is broken, v is released.
		go func() {

			// Defer removal of v's handle from the export table to the end of this function
			defer func() {
				r.lk.Lock()
				delete(r.live, importer)
				r.lk.Unlock()
				// DropPtr/forget all exported handles
				r.exp.RemoveImporter(importer)
			}()

			conn, err := r.dialer.Dial(importer)
			if err != nil {
				println("problem dialing lifeline to", importer.String(), err.Error())
				return
			}
			defer conn.Close()

			if conn.Write(&dontReplyMsg{}) != nil {
				println("problem writing on lifeline to", importer.String(), err.Error())
				return
			}
			// Read returns when the remote dies and
			// runs the conn into an error
			conn.Read()
		}()
	}
	return &ptrMsg{ID: exph.ID, TypeID: exph.Type.ID}
}
Esempio n. 2
0
func getReducerTop(addr circuit.Addr, lk *sync.Mutex, top *SortablePosts) {
	// Obtain cross-runtime pointer to reducer service on the worker owning file f
	x, err := circuit.TryDial(addr, "reducer-service")
	if err != nil {
		println("dial", addr.String(), "error", err.Error())
		// Skip reducers that seem to be dead
		return
	}
	// Catch panics due to dead worker and return empty list of top ten posts in this case
	defer func() {
		if p := recover(); p != nil {
			fmt.Fprintf(os.Stderr, "%s.Top panic: %#v\n", x.String(), p)
		}
	}()
	// Fetch top ten posts
	rtop := x.Call("Top")[0].([]*Post)
	lk.Lock()
	defer lk.Unlock()
	println("Reducer", addr.String(), "contributed", len(rtop), "posts")
	(*top) = append(*top, rtop...)
}