package network import ( "container/list" "errors" "sync" "time" pb "github.com/micro/go-micro/network/proto" ) var ( // MaxDepth defines max depth of peer topology MaxDepth uint = 3 ) var ( // ErrPeerExists is returned when adding a peer which already exists ErrPeerExists = errors.New("peer already exists") // ErrPeerNotFound is returned when a peer could not be found in node topology ErrPeerNotFound = errors.New("peer not found") ) // node is network node type node struct { sync.RWMutex // id is node id id string // address is node address address string // peers are nodes with direct link to this node peers map[string]*node // network returns the node network network Network // lastSeen keeps track of node lifetime and updates lastSeen time.Time } // Id is node ide func (n *node) Id() string { return n.id } // Address returns node address func (n *node) Address() string { return n.address } // Network returns node network func (n *node) Network() Network { return n.network } // walk walks the node graph until some condition is met func (n *node) walk(until func(peer *node) bool, action func(parent, peer *node)) map[string]*node { // track the visited nodes visited := make(map[string]*node) // queue of the nodes to visit queue := list.New() // push node to the back of queue queue.PushBack(n) // mark the node as visited visited[n.id] = n // keep iterating over the queue until its empty for queue.Len() > 0 { // pop the node from the front of the queue qnode := queue.Front() if until(qnode.Value.(*node)) { return visited } // iterate through all of the node peers // mark the visited nodes; enqueue the non-visted for id, peer := range qnode.Value.(*node).peers { if _, ok := visited[id]; !ok { visited[id] = peer action(qnode.Value.(*node), peer) queue.PushBack(peer) } } // remove the node from the queue queue.Remove(qnode) } return visited } // AddPeer adds a new peer to node topology // It returns false if the peer already exists func (n *node) AddPeer(peer *node) error { n.Lock() defer n.Unlock() if _, ok := n.peers[peer.id]; !ok { n.peers[peer.id] = peer return nil } return ErrPeerExists } // DeletePeer deletes a peer from node peers // It returns true if the peer has been deleted func (n *node) DeletePeer(id string) bool { n.Lock() defer n.Unlock() delete(n.peers, id) return true } // UpdatePeer updates a peer if it already exists // It returns error if the peer does not exist func (n *node) UpdatePeer(peer *node) error { n.Lock() defer n.Unlock() if _, ok := n.peers[peer.id]; ok { n.peers[peer.id] = peer return nil } return ErrPeerNotFound } // RefreshPeer updates node timestamp // It returns false if the peer has not been found. func (n *node) RefreshPeer(id string, now time.Time) error { n.Lock() defer n.Unlock() peer, ok := n.peers[id] if !ok { return ErrPeerNotFound } if peer.lastSeen.Before(now) { peer.lastSeen = now } return nil } // Nodes returns a slice of all nodes in the whole node topology func (n *node) Nodes() []Node { // we need to freeze the network graph here // otherwise we might get inconsisten results n.RLock() defer n.RUnlock() // NOTE: this should never be true untilNoMorePeers := func(node *node) bool { return node == nil } justWalk := func(parent, node *node) {} visited := n.walk(untilNoMorePeers, justWalk) var nodes []Node // collect all the nodes and return them for _, node := range visited { nodes = append(nodes, node) } return nodes } // GetPeerNode returns a node from node MaxDepth topology // It returns nil if the peer was not found func (n *node) GetPeerNode(id string) *node { // get node topology up to MaxDepth top := n.Topology(MaxDepth) untilFoundPeer := func(n *node) bool { return n.id == id } justWalk := func(paent, node *node) {} visited := top.walk(untilFoundPeer, justWalk) peerNode, ok := visited[id] if !ok { return nil } return peerNode } // DeletePeerNode removes peer node from node topology func (n *node) DeletePeerNode(id string) error { n.Lock() defer n.Unlock() untilNoMorePeers := func(node *node) bool { return node == nil } deleted := make(map[string]*node) deletePeer := func(parent, node *node) { if node.id != n.id && node.id == id { delete(parent.peers, node.id) deleted[node.id] = node } } n.walk(untilNoMorePeers, deletePeer) if _, ok := deleted[id]; !ok { return ErrPeerNotFound } return nil } // PruneStalePeerNodes prune the peers that have not been seen for longer than given time // It returns a map of the the nodes that got pruned func (n *node) PruneStalePeerNodes(pruneTime time.Duration) map[string]*node { n.Lock() defer n.Unlock() untilNoMorePeers := func(node *node) bool { return node == nil } pruned := make(map[string]*node) pruneStalePeer := func(parent, node *node) { if node.id != n.id && time.Since(node.lastSeen) > PruneTime { delete(parent.peers, node.id) pruned[node.id] = node } } n.walk(untilNoMorePeers, pruneStalePeer) return pruned } // getTopology traverses node graph and builds node topology // NOTE: this function is not thread safe func (n *node) getTopology(depth uint) *node { // make a copy of yourself node := &node{ id: n.id, address: n.address, peers: make(map[string]*node), network: n.network, lastSeen: n.lastSeen, } // return if we reach requested depth or we have no more peers if depth == 0 || len(n.peers) == 0 { return node } // decrement the depth depth-- // iterate through our peers and update the node peers for _, peer := range n.peers { nodePeer := peer.getTopology(depth) if _, ok := node.peers[nodePeer.id]; !ok { node.peers[nodePeer.id] = nodePeer } } return node } // Topology returns a copy of the node topology down to given depth // NOTE: the returned node is a node graph - not a single node func (n *node) Topology(depth uint) *node { n.RLock() defer n.RUnlock() return n.getTopology(depth) } // Peers returns node peers up to MaxDepth func (n *node) Peers() []Node { n.RLock() defer n.RUnlock() peers := make([]Node, 0, len(n.peers)) for _, nodePeer := range n.peers { peer := nodePeer.getTopology(MaxDepth) peers = append(peers, peer) } return peers } // UnpackPeerTopology unpacks pb.Peer into node topology of given depth func UnpackPeerTopology(pbPeer *pb.Peer, lastSeen time.Time, depth uint) *node { peerNode := &node{ id: pbPeer.Node.Id, address: pbPeer.Node.Address, peers: make(map[string]*node), lastSeen: lastSeen, } // return if have either reached the depth or have no more peers if depth == 0 || len(pbPeer.Peers) == 0 { return peerNode } // decrement the depth depth-- peers := make(map[string]*node) for _, pbPeer := range pbPeer.Peers { peer := UnpackPeerTopology(pbPeer, lastSeen, depth) peers[pbPeer.Node.Id] = peer } peerNode.peers = peers return peerNode } func peerProtoTopology(peer Node, depth uint) *pb.Peer { node := &pb.Node{ Id: peer.Id(), Address: peer.Address(), } // set the network name if network is not nil if peer.Network() != nil { node.Network = peer.Network().Name() } pbPeers := &pb.Peer{ Node: node, Peers: make([]*pb.Peer, 0), } // return if we reached the end of topology or depth if depth == 0 || len(peer.Peers()) == 0 { return pbPeers } // decrement the depth depth-- // iterate through peers of peers aka pops for _, pop := range peer.Peers() { peer := peerProtoTopology(pop, depth) pbPeers.Peers = append(pbPeers.Peers, peer) } return pbPeers } // PeersToProto returns node peers graph encoded into protobuf func PeersToProto(node Node, depth uint) *pb.Peer { // network node aka root node pbNode := &pb.Node{ Id: node.Id(), Address: node.Address(), } // set the network name if network is not nil if node.Network() != nil { pbNode.Network = node.Network().Name() } // we will build proto topology into this pbPeers := &pb.Peer{ Node: pbNode, Peers: make([]*pb.Peer, 0), } for _, peer := range node.Peers() { pbPeer := peerProtoTopology(peer, depth) pbPeers.Peers = append(pbPeers.Peers, pbPeer) } return pbPeers }