// GetAllocs is used to request allocations for a specific node
func (n *Node) GetAllocs(args *structs.NodeSpecificRequest,
	reply *structs.NodeAllocsResponse) error {
	if done, err := n.srv.forward("Node.GetAllocs", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "client", "get_allocs"}, time.Now())

	// Verify the arguments
	if args.NodeID == "" {
		return fmt.Errorf("missing node ID")
	}

	// Setup the blocking query
	opts := blockingOptions{
		queryOpts: &args.QueryOptions,
		queryMeta: &reply.QueryMeta,
		watch:     watch.NewItems(watch.Item{AllocNode: args.NodeID}),
		run: func() error {
			// Look for the node
			snap, err := n.srv.fsm.State().Snapshot()
			if err != nil {
				return err
			}
			allocs, err := snap.AllocsByNode(args.NodeID)
			if err != nil {
				return err
			}

			// Setup the output
			if len(allocs) != 0 {
				reply.Allocs = allocs
				for _, alloc := range allocs {
					reply.Index = maxUint64(reply.Index, alloc.ModifyIndex)
				}
			} else {
				reply.Allocs = nil

				// Use the last index that affected the nodes table
				index, err := snap.Index("allocs")
				if err != nil {
					return err
				}

				// Must provide non-zero index to prevent blocking
				// Index 1 is impossible anyways (due to Raft internals)
				if index == 0 {
					reply.Index = 1
				} else {
					reply.Index = index
				}
			}
			return nil
		}}
	return n.srv.blockingRPC(&opts)
}

func (s *HTTPServer) nodeAllocations(resp http.ResponseWriter, req *http.Request,
	nodeID string) (interface{}, error) {
	if req.Method != "GET" {
		return nil, CodedError(405, ErrInvalidMethod)
	}
	args := structs.NodeSpecificRequest{
		NodeID: nodeID,
	}
	if s.parse(resp, req, &args.Region, &args.QueryOptions) {
		return nil, nil
	}

	var out structs.NodeAllocsResponse
	if err := s.agent.RPC("Node.GetAllocs", &args, &out); err != nil {
		return nil, err
	}

	setMeta(resp, &out.QueryMeta)
	if out.Allocs == nil {
		out.Allocs = make([]*structs.Allocation, 0)
	}
	return out.Allocs, nil
}