package network import ( "errors" "fmt" "io" "net" "runtime/debug" "sort" "strconv" "sync" "time" "github.com/google/uuid" "github.com/micro/go-micro/registry" "github.com/micro/go-micro/network/transport" "github.com/micro/go-micro/util/addr" "github.com/micro/go-micro/util/log" pb "github.com/micro/go-micro/network/proto" ) type node struct { *network // closed channel to close our connection to the network closed chan bool sync.RWMutex // the nodes unique micro assigned mac address muid string // the node id registered in registry id string // address of this node registered in registry address string // our network lease with our network id/address lease *pb.Lease // the node registry registry registry.Registry // the base level transport transport transport.Transport // the listener listener transport.Listener // connected records // record.Address:true connected map[string]bool // leases for connections to us // link remote node:link links map[string][]*link // messages received over links recv chan *Message // messages received over links send chan *Message } // network methods func newNode(n *network) (*node, error) { // create a new node node := &node{ // this nodes unique micro assigned mac address muid: fmt.Sprintf("%s-%s", n.name, uuid.New().String()), // map of connected records connected: make(map[string]bool), // the links links: make(map[string][]*link), // closed channel closed: make(chan bool), // set the nodes network network: n, // set the default transport transport: transport.DefaultTransport, // set the default registry registry: registry.DefaultRegistry, // receive channel for accepted connections recv: make(chan *Message, 128), // send channel for accepted connections send: make(chan *Message, 128), } // get the transport we're going to use for our tunnels // TODO: set to quic or tunnel or something else t, ok := n.Options.Values().Get("network.transport") if ok { node.transport = t.(transport.Transport) } // register the node with the registry for the network // TODO: use a registrar or something else for local things r, ok := n.Options.Values().Get("network.registry") if ok { node.registry = r.(registry.Registry) } // we listen on a random address, this is not advertised // TODO: use util/addr to get something anyone in the same private network can talk to l, err := node.transport.Listen(":0") if err != nil { return nil, err } // set the listener node.listener = l node.address = l.Addr() // TODO: start the router and broadcast advertisements // receive updates and push them to the network in accept(l) below // chan, err := n.router.Advertise() // u <- chan // socket.send("route", u) // u := socket.recv() => r.router.Update(u) // process any incoming messages on the listener // this is our inbound network connection go node.accept(l) // process any messages being sent by node.Send // forwards to every link we have go node.process() var port int // TODO: this should be an overlay address // ideally received via some dhcp style broadcast host, pp, err := net.SplitHostPort(l.Addr()) if err == nil { pt, _ := strconv.Atoi(pp) port = pt } // some horrible things are happening if host == "::" { host = "" } // set the address addr, _ := addr.Extract(host) // used to register in registry for network resolution // separate to our lease on the network itself node.id = uuid.New().String() node.address = fmt.Sprintf("%s:%d", addr, port) // register self with the registry using network: prefix // this is a local registry of nodes separate to the resolver // maybe consolidate registry/resolver // TODO: find a way to do this via gossip or something like // a registrar or tld or whatever if err := node.registry.Register(®istry.Service{ // register with the network id Name: n.Name(), Nodes: []*registry.Node{ {Id: node.id, Address: addr, Port: port}, }, }); err != nil { node.Close() return nil, err } // create a channel to get links linkChan := make(chan *link, 1) // we're going to wait for the first connection go node.connect(linkChan) // wait forever to connect // TODO: do something with the links we receive link := <-linkChan // process this link log.Debugf("connect managing link %s", link.id) go node.manage(link) go func() { for { // process any further new links select { case l := <-linkChan: log.Debugf("Managing new link %s", l.id) go node.manage(l) case <-node.closed: return } } }() return node, nil } // node methods // Accept processes the incoming messages on its listener. // This listener was created with the first call to network.Connect. // Any inbound new socket here is essentially something else attempting // to connect to the network. So we turn it into a socket, then process it. func (n *node) accept(l transport.Listener) error { return l.Accept(func(sock transport.Socket) { defer func() { // close socket sock.Close() if r := recover(); r != nil { log.Log("panic recovered: ", r) log.Log(string(debug.Stack())) } }() // create a new link link := newLink(n, sock, nil) log.Debugf("Accepting connection from %s", link.socket.Remote()) // wait for the link to be connected // the remote end will send "Connect" // and we will return a "Lease" if err := link.accept(); err != nil { log.Debugf("Error accepting connection %v", err) return } log.Debugf("Accepted link from %s", link.socket.Remote()) // save with the muid as the key // where we attempt to connect to nodes // we do not connect to the same thing // TODO: figure out why this is an issue // When we receive a connection from ourself // we can't maintain the two links separately // so we don't save it. It's basically some // weird loopback issue because its our own socket. if n.muid != link.lease.Node.Muid { n.Lock() // get the links links := n.links[link.lease.Node.Muid] // append to the current links links = append(links, link) // save the links with muid as the key n.links[link.lease.Node.Muid] = links n.Unlock() } // manage the link for its lifetime log.Debugf("managing the link now %s", link.id) n.manage(link) }) } // processes the sends the messages from n.Send into the queue of // each link. If multiple links exist for a muid it should only // send on link to figure it out. // If we connected to a record and that link goes down we should // also remove it from the n.connected map. func (n *node) process() { for { select { case <-n.closed: return // process outbound messages on the send queue // these messages are received from n.Send case m := <-n.send: // queue the message on each link // TODO: more than likely use proxy n.RLock() // range over all the links for _, links := range n.links { if len(links) == 0 { continue } // sort the links by weight sort.Slice(links, func(i, j int) bool { return links[i].Weight() < links[j].Weight() }) // queue the message links[0].Send(m) } n.RUnlock() } } } // Manage manages the link for its lifetime. It should ideally throw // away the link in the n.links map if there's any issues or total disconnection // it should look at link.Status. // If we connected to a record and that link goes down we should // also remove it from the n.connected map. func (n *node) manage(l *link) { // now process inbound messages on the link // assumption is this handles everything else for { // the send side uses a link queue but the receive side immediately sends it // ideally we should probably have an internal queue on that side as well // so we can judge link saturation both ways. m, err := l.Accept() if err == io.EOF { return } if err != nil { log.Debugf("Error accepting message on link %s: %v", l.id, err) // ??? return } // if the node connection is closed bail out select { case <-n.closed: return // send to the network recv channel e.g node.Accept() case n.recv <- m: } } } // connect attempts to periodically connect to new nodes in the network. // It will only do this if it has less than 3 connections. this method // is called by network.Connect and fired in a go routine after establishing // the first connection and creating a node. The node attempts to maintain // its connection to the network via multiple links. func (n *node) connect(linkChan chan *link) { // TODO: adjustable ticker t := time.NewTicker(time.Second) var lease *pb.Lease for { select { // exit when told to do so case <-n.closed: return // on every tick check the number of links and then attempt // to connect to new nodes if we don't have sufficient links case <-t.C: n.RLock() // only start processing if we have less than 3 links conns := len(n.links) if conns > 2 { n.RUnlock() continue } // get a list of link addresses so we don't reconnect // to the ones we're already connected to connected := n.connected // unlock our read lock n.RUnlock() // lookup records for our network records := n.network.lookup(n.registry) // for each record check we haven't already got a connection // attempt to dial it, create a new socket and call // connect with our existing network lease. // if its the first call we don't actually have a lease // TODO: determine how to prioritise local records // while still connecting to the global network for _, record := range records { // skip existing connections if connected[record.Address] { log.Tracef("Skipping connection to %s", record.Address) continue } // check how many connections we have if conns > 2 { log.Debugf("Made enough connections") break } // attempt to connect and create a link log.Debugf("Dialing connection to %s", record.Address) // connect to the node sock, err := n.transport.Dial(record.Address) if err != nil { log.Debugf("Dialing connection error %v", err) continue } // create a new link with the lease and socket link := newLink(n, sock, lease) log.Debugf("Connecting link to %s", record.Address) // connect the link: // this broadcasts a "connect" request and gets back a "lease" // this is the tunnel to the outside world and to the network // then push updates and messages over this link // first connect will not have a lease so we get one with node id/address if err := link.connect(); err != nil { // shit continue } log.Debugf("Connected link to %s", record.Address) n.Lock() // set lease for next time we connect to anything else // we want to use the same lease for that. in future // we may have to expire the lease lease = link.lease // save the new link // get existing links using the lease author links := n.links[lease.Author] // append to the links links = append(links, link) // save the links using the author n.links[lease.Author] = links n.Unlock() // update number of connections conns++ // save the connection n.Lock() n.connected[record.Address] = true n.Unlock() // drop this down the link channel to the network // so it can manage the links linkChan <- link } } } } func (n *node) Address() string { n.RLock() defer n.RUnlock() // we have no address yet if n.lease == nil { return "" } // return node address in the lease return n.lease.Node.Address } // Close shutdowns all the links and closes the listener func (n *node) Close() error { select { case <-n.closed: return nil default: // mark as closed, we're now useless and there's no coming back close(n.closed) // shutdown all the links n.Lock() for muid, links := range n.links { for _, link := range links { link.Close() } delete(n.links, muid) } // reset connected n.connected = nil n.Unlock() // deregister self n.registry.Deregister(®istry.Service{ Name: n.network.Name(), Nodes: []*registry.Node{ {Id: n.id, Address: n.address}, }, }) // shutdown the listener return n.listener.Close() } return nil } // Accept receives the incoming messages from all links func (n *node) Accept() (*Message, error) { // process the inbound cruft for { select { case m, ok := <-n.recv: if !ok { return nil, errors.New("connection closed") } // return the message return m, nil case <-n.closed: return nil, errors.New("connection closed") } } // we never get here return nil, nil } func (n *node) Id() string { n.RLock() defer n.RUnlock() if n.lease == nil { return "" } return n.lease.Node.Id } func (n *node) Network() string { return n.network.Name() } // Send propagates a message over all links. This should probably use its proxy. func (n *node) Send(m *Message) error { select { case <-n.closed: return errors.New("connection closed") case n.send <- m: // send the message } return nil }