micro/network/default.go
2019-12-10 11:46:13 +00:00

1380 lines
34 KiB
Go

package network
import (
"errors"
"fmt"
"hash/fnv"
"io"
"math"
"sync"
"time"
"github.com/golang/protobuf/proto"
"github.com/micro/go-micro/client"
rtr "github.com/micro/go-micro/client/selector/router"
"github.com/micro/go-micro/network/resolver/dns"
pbNet "github.com/micro/go-micro/network/service/proto"
"github.com/micro/go-micro/proxy"
"github.com/micro/go-micro/router"
pbRtr "github.com/micro/go-micro/router/service/proto"
"github.com/micro/go-micro/server"
"github.com/micro/go-micro/transport"
"github.com/micro/go-micro/tunnel"
bun "github.com/micro/go-micro/tunnel/broker"
tun "github.com/micro/go-micro/tunnel/transport"
"github.com/micro/go-micro/util/backoff"
"github.com/micro/go-micro/util/log"
)
var (
// NetworkChannel is the name of the tunnel channel for passing network messages
NetworkChannel = "network"
// ControlChannel is the name of the tunnel channel for passing control message
ControlChannel = "control"
// DefaultLink is default network link
DefaultLink = "network"
// MaxConnections is the max number of network client connections
MaxConnections = 3
)
var (
// ErrClientNotFound is returned when client for tunnel channel could not be found
ErrClientNotFound = errors.New("client not found")
// ErrPeerLinkNotFound is returned when peer link could not be found in tunnel Links
ErrPeerLinkNotFound = errors.New("peer link not found")
)
// network implements Network interface
type network struct {
// node is network node
*node
// options configure the network
options Options
// rtr is network router
router router.Router
// prx is network proxy
proxy proxy.Proxy
// tun is network tunnel
tunnel tunnel.Tunnel
// server is network server
server server.Server
// client is network client
client client.Client
// tunClient is a map of tunnel clients keyed over tunnel channel names
tunClient map[string]transport.Client
// peerLinks is a map of links for each peer
peerLinks map[string]tunnel.Link
sync.RWMutex
// connected marks the network as connected
connected bool
// closed closes the network
closed chan bool
// whether we've discovered by the network
discovered chan bool
// solicted checks whether routes were solicited by one node
solicited chan *node
}
// message is network message
type message struct {
// msg is transport message
msg *transport.Message
// session is tunnel session
session tunnel.Session
}
// newNetwork returns a new network node
func newNetwork(opts ...Option) Network {
options := DefaultOptions()
for _, o := range opts {
o(&options)
}
// set the address to a hashed address
hasher := fnv.New64()
hasher.Write([]byte(options.Address + options.Id))
address := fmt.Sprintf("%d", hasher.Sum64())
// set the address to advertise
var advertise string
var peerAddress string
if len(options.Advertise) > 0 {
advertise = options.Advertise
peerAddress = options.Advertise
} else {
advertise = options.Address
peerAddress = address
}
// init tunnel address to the network bind address
options.Tunnel.Init(
tunnel.Address(options.Address),
)
// init router Id to the network id
options.Router.Init(
router.Id(options.Id),
router.Address(peerAddress),
)
// create tunnel client with tunnel transport
tunTransport := tun.NewTransport(
tun.WithTunnel(options.Tunnel),
)
// create the tunnel broker
tunBroker := bun.NewBroker(
bun.WithTunnel(options.Tunnel),
)
// server is network server
server := server.NewServer(
server.Id(options.Id),
server.Address(peerAddress),
server.Advertise(advertise),
server.Name(options.Name),
server.Transport(tunTransport),
server.Broker(tunBroker),
)
// client is network client
client := client.NewClient(
client.Broker(tunBroker),
client.Transport(tunTransport),
client.Selector(
rtr.NewSelector(
rtr.WithRouter(options.Router),
),
),
)
network := &network{
node: &node{
id: options.Id,
address: peerAddress,
peers: make(map[string]*node),
},
options: options,
router: options.Router,
proxy: options.Proxy,
tunnel: options.Tunnel,
server: server,
client: client,
tunClient: make(map[string]transport.Client),
peerLinks: make(map[string]tunnel.Link),
discovered: make(chan bool, 1),
solicited: make(chan *node, 1),
}
network.node.network = network
return network
}
func (n *network) Init(opts ...Option) error {
n.Lock()
defer n.Unlock()
// TODO: maybe only allow reinit of certain opts
for _, o := range opts {
o(&n.options)
}
return nil
}
// Options returns network options
func (n *network) Options() Options {
n.RLock()
defer n.RUnlock()
options := n.options
return options
}
// Name returns network name
func (n *network) Name() string {
return n.options.Name
}
// acceptNetConn accepts connections from NetworkChannel
func (n *network) acceptNetConn(l tunnel.Listener, recv chan *message) {
var i int
for {
// accept a connection
conn, err := l.Accept()
if err != nil {
sleep := backoff.Do(i)
log.Debugf("Network tunnel [%s] accept error: %v, backing off for %v", ControlChannel, err, sleep)
time.Sleep(sleep)
if i > 5 {
i = 0
}
i++
continue
}
select {
case <-n.closed:
if err := conn.Close(); err != nil {
log.Debugf("Network tunnel [%s] failed to close connection: %v", NetworkChannel, err)
}
return
default:
// go handle NetworkChannel connection
go n.handleNetConn(conn, recv)
}
}
}
// acceptCtrlConn accepts connections from ControlChannel
func (n *network) acceptCtrlConn(l tunnel.Listener, recv chan *message) {
var i int
for {
// accept a connection
conn, err := l.Accept()
if err != nil {
sleep := backoff.Do(i)
log.Debugf("Network tunnel [%s] accept error: %v, backing off for %v", ControlChannel, err, sleep)
time.Sleep(sleep)
if i > 5 {
// reset the counter
i = 0
}
i++
continue
}
select {
case <-n.closed:
if err := conn.Close(); err != nil {
log.Debugf("Network tunnel [%s] failed to close connection: %v", ControlChannel, err)
}
return
default:
// go handle ControlChannel connection
go n.handleCtrlConn(conn, recv)
}
}
}
// handleCtrlConn handles ControlChannel connections
// advertise advertises routes to the network
func (n *network) advertise(advertChan <-chan *router.Advert) {
hasher := fnv.New64()
for {
select {
// process local adverts and randomly fire them at other nodes
case advert := <-advertChan:
// create a proto advert
var events []*pbRtr.Event
for _, event := range advert.Events {
// the routes service address
address := event.Route.Address
// only hash the address if we're advertising our own local routes
if event.Route.Router == advert.Id {
// hash the service before advertising it
hasher.Reset()
// routes for multiple instances of a service will be collapsed here.
// TODO: once we store labels in the table this may need to change
// to include the labels in case they differ but highly unlikely
hasher.Write([]byte(event.Route.Service + n.node.Address()))
address = fmt.Sprintf("%d", hasher.Sum64())
}
// calculate route metric to advertise
metric := n.getRouteMetric(event.Route.Router, event.Route.Gateway, event.Route.Link)
// NOTE: we override Gateway, Link and Address here
route := &pbRtr.Route{
Service: event.Route.Service,
Address: address,
Gateway: n.node.Address(),
Network: event.Route.Network,
Router: event.Route.Router,
Link: DefaultLink,
Metric: metric,
}
e := &pbRtr.Event{
Type: pbRtr.EventType(event.Type),
Timestamp: event.Timestamp.UnixNano(),
Route: route,
}
events = append(events, e)
}
msg := &pbRtr.Advert{
Id: advert.Id,
Type: pbRtr.AdvertType(advert.Type),
Timestamp: advert.Timestamp.UnixNano(),
Events: events,
}
// send the advert to all on the control channel
// since its not a solicitation
if advert.Type != router.Solicitation {
if err := n.sendMsg("advert", ControlChannel, msg); err != nil {
log.Debugf("Network failed to advertise routes: %v", err)
}
continue
}
// it's a solication, someone asked for it
// so we're going to pick off the node and send it
select {
case peer := <-n.solicited:
// someone requested the route
n.sendTo("advert", ControlChannel, peer, msg)
default:
// send to all since we can't get anything
n.sendMsg("advert", ControlChannel, msg)
}
case <-n.closed:
return
}
}
}
func (n *network) initNodes(startup bool) {
nodes, err := n.resolveNodes()
if err != nil && !startup {
log.Debugf("Network failed to resolve nodes: %v", err)
return
}
// initialize the tunnel
log.Tracef("Network initialising nodes %+v\n", nodes)
n.tunnel.Init(
tunnel.Nodes(nodes...),
)
}
// resolveNodes resolves network nodes to addresses
func (n *network) resolveNodes() ([]string, error) {
// resolve the network address to network nodes
records, err := n.options.Resolver.Resolve(n.options.Name)
if err != nil {
log.Debugf("Network failed to resolve nodes: %v", err)
}
// keep processing
nodeMap := make(map[string]bool)
// collect network node addresses
//nolint:prealloc
var nodes []string
var i int
for _, record := range records {
if _, ok := nodeMap[record.Address]; ok {
continue
}
nodeMap[record.Address] = true
nodes = append(nodes, record.Address)
i++
// break once MaxConnection nodes has been reached
if i == MaxConnections {
break
}
}
// use the dns resolver to expand peers
dns := &dns.Resolver{}
// append seed nodes if we have them
for _, node := range n.options.Nodes {
// resolve anything that looks like a host name
records, err := dns.Resolve(node)
if err != nil {
log.Debugf("Failed to resolve %v %v", node, err)
continue
}
// add to the node map
for _, record := range records {
if _, ok := nodeMap[record.Address]; !ok {
nodes = append(nodes, record.Address)
}
}
}
return nodes, nil
}
// handleNetConn handles network announcement messages
func (n *network) handleNetConn(s tunnel.Session, msg chan *message) {
for {
m := new(transport.Message)
if err := s.Recv(m); err != nil {
log.Debugf("Network tunnel [%s] receive error: %v", NetworkChannel, err)
switch err {
case io.EOF, tunnel.ErrReadTimeout:
s.Close()
return
}
continue
}
// check if peer is set
peer := m.Header["Micro-Peer"]
// check who the message is intended for
if len(peer) > 0 && peer != n.options.Id {
continue
}
select {
case msg <- &message{
msg: m,
session: s,
}:
case <-n.closed:
return
}
}
}
func (n *network) handleCtrlConn(s tunnel.Session, msg chan *message) {
for {
m := new(transport.Message)
if err := s.Recv(m); err != nil {
log.Debugf("Network tunnel [%s] receive error: %v", ControlChannel, err)
switch err {
case io.EOF, tunnel.ErrReadTimeout:
s.Close()
return
}
continue
}
// check if peer is set
peer := m.Header["Micro-Peer"]
// check who the message is intended for
if len(peer) > 0 && peer != n.options.Id {
continue
}
select {
case msg <- &message{
msg: m,
session: s,
}:
case <-n.closed:
return
}
}
}
// getHopCount queries network graph and returns hop count for given router
// - Routes for local services have hop count 1
// - Routes with ID of adjacent nodes have hop count 2
// - Routes by peers of the advertiser have hop count 3
// - Routes beyond node neighbourhood have hop count 4
func (n *network) getHopCount(rtr string) int {
// make sure node.peers are not modified
n.node.RLock()
defer n.node.RUnlock()
// we are the origin of the route
if rtr == n.options.Id {
return 1
}
// the route origin is our peer
if _, ok := n.peers[rtr]; ok {
return 10
}
// the route origin is the peer of our peer
for _, peer := range n.peers {
for id := range peer.peers {
if rtr == id {
return 100
}
}
}
// otherwise we are three hops away
return 1000
}
// getRouteMetric calculates router metric and returns it
// Route metric is calculated based on link status and route hopd count
func (n *network) getRouteMetric(router string, gateway string, link string) int64 {
// set the route metric
n.RLock()
defer n.RUnlock()
// local links are marked as 1
if link == "local" && gateway == "" {
return 1
}
// local links from other gateways as 2
if link == "local" && gateway != "" {
return 2
}
log.Tracef("Network looking up %s link to gateway: %s", link, gateway)
// attempt to find link based on gateway address
lnk, ok := n.peerLinks[gateway]
if !ok {
log.Debugf("Network failed to find a link to gateway: %s", gateway)
// no link found so infinite metric returned
return math.MaxInt64
}
// calculating metric
delay := lnk.Delay()
hops := n.getHopCount(router)
length := lnk.Length()
// make sure delay is non-zero
if delay == 0 {
delay = 1
}
// make sure length is non-zero
if length == 0 {
log.Debugf("Link length is 0 %v %v", link, lnk.Length())
length = 10e9
}
log.Tracef("Network calculated metric %v delay %v length %v distance %v", (delay*length*int64(hops))/10e6, delay, length, hops)
return (delay * length * int64(hops)) / 10e6
}
// processCtrlChan processes messages received on ControlChannel
func (n *network) processCtrlChan(listener tunnel.Listener) {
defer listener.Close()
// receive control message queue
recv := make(chan *message, 128)
// accept ControlChannel cconnections
go n.acceptCtrlConn(listener, recv)
for {
select {
case m := <-recv:
// switch on type of message and take action
switch m.msg.Header["Micro-Method"] {
case "advert":
pbRtrAdvert := &pbRtr.Advert{}
if err := proto.Unmarshal(m.msg.Body, pbRtrAdvert); err != nil {
log.Debugf("Network fail to unmarshal advert message: %v", err)
continue
}
// don't process your own messages
if pbRtrAdvert.Id == n.options.Id {
continue
}
log.Debugf("Network received advert message from: %s", pbRtrAdvert.Id)
// loookup advertising node in our peer topology
advertNode := n.node.GetPeerNode(pbRtrAdvert.Id)
if advertNode == nil {
// if we can't find the node in our topology (MaxDepth) we skipp prcessing adverts
log.Debugf("Network skipping advert message from unknown peer: %s", pbRtrAdvert.Id)
continue
}
var events []*router.Event
for _, event := range pbRtrAdvert.Events {
// we know the advertising node is not the origin of the route
if pbRtrAdvert.Id != event.Route.Router {
// if the origin router is not the advertising node peer
// we can't rule out potential routing loops so we bail here
if peer := advertNode.GetPeerNode(event.Route.Router); peer == nil {
log.Debugf("Network skipping advert message from peer: %s", pbRtrAdvert.Id)
continue
}
}
route := router.Route{
Service: event.Route.Service,
Address: event.Route.Address,
Gateway: event.Route.Gateway,
Network: event.Route.Network,
Router: event.Route.Router,
Link: event.Route.Link,
Metric: event.Route.Metric,
}
// calculate route metric and add to the advertised metric
// we need to make sure we do not overflow math.MaxInt64
metric := n.getRouteMetric(event.Route.Router, event.Route.Gateway, event.Route.Link)
log.Tracef("Network metric for router %s and gateway %s: %v", event.Route.Router, event.Route.Gateway, metric)
// check we don't overflow max int 64
if d := route.Metric + metric; d <= 0 {
// set to max int64 if we overflow
route.Metric = math.MaxInt64
} else {
// set the combined value of metrics otherwise
route.Metric = d
}
// create router event
e := &router.Event{
Type: router.EventType(event.Type),
Timestamp: time.Unix(0, pbRtrAdvert.Timestamp),
Route: route,
}
events = append(events, e)
}
// if no events are eligible for processing continue
if len(events) == 0 {
log.Tracef("Network no events to be processed by router: %s", n.options.Id)
continue
}
// create an advert and process it
advert := &router.Advert{
Id: pbRtrAdvert.Id,
Type: router.AdvertType(pbRtrAdvert.Type),
Timestamp: time.Unix(0, pbRtrAdvert.Timestamp),
TTL: time.Duration(pbRtrAdvert.Ttl),
Events: events,
}
log.Tracef("Network router %s processing advert: %s", n.Id(), advert.Id)
if err := n.router.Process(advert); err != nil {
log.Debugf("Network failed to process advert %s: %v", advert.Id, err)
}
case "solicit":
pbRtrSolicit := &pbRtr.Solicit{}
if err := proto.Unmarshal(m.msg.Body, pbRtrSolicit); err != nil {
log.Debugf("Network fail to unmarshal solicit message: %v", err)
continue
}
log.Debugf("Network received solicit message from: %s", pbRtrSolicit.Id)
// ignore solicitation when requested by you
if pbRtrSolicit.Id == n.options.Id {
continue
}
log.Tracef("Network router flushing routes for: %s", pbRtrSolicit.Id)
// advertise all the routes when a new node has connected
if err := n.router.Solicit(); err != nil {
log.Debugf("Network failed to solicit routes: %s", err)
}
peer := &node{
id: pbRtrSolicit.Id,
link: m.msg.Header["Micro-Link"],
}
// specify that someone solicited the route
select {
case n.solicited <- peer:
default:
// don't block
}
}
case <-n.closed:
return
}
}
}
// processNetChan processes messages received on NetworkChannel
func (n *network) processNetChan(listener tunnel.Listener) {
defer listener.Close()
// receive network message queue
recv := make(chan *message, 128)
// accept NetworkChannel connections
go n.acceptNetConn(listener, recv)
for {
select {
case m := <-recv:
// switch on type of message and take action
switch m.msg.Header["Micro-Method"] {
case "connect":
// mark the time the message has been received
now := time.Now()
pbNetConnect := &pbNet.Connect{}
if err := proto.Unmarshal(m.msg.Body, pbNetConnect); err != nil {
log.Debugf("Network tunnel [%s] connect unmarshal error: %v", NetworkChannel, err)
continue
}
// don't process your own messages
if pbNetConnect.Node.Id == n.options.Id {
continue
}
log.Debugf("Network received connect message from: %s", pbNetConnect.Node.Id)
peer := &node{
id: pbNetConnect.Node.Id,
address: pbNetConnect.Node.Address,
link: m.msg.Header["Micro-Link"],
peers: make(map[string]*node),
lastSeen: now,
}
// update peer links
if err := n.updatePeerLinks(peer); err != nil {
log.Debugf("Network failed updating peer links: %s", err)
}
// add peer to the list of node peers
if err := n.node.AddPeer(peer); err == ErrPeerExists {
log.Tracef("Network peer exists, refreshing: %s", peer.id)
// update lastSeen time for the existing node
if err := n.RefreshPeer(peer.id, peer.link, now); err != nil {
log.Debugf("Network failed refreshing peer %s: %v", peer.id, err)
}
}
// we send the peer message because someone has sent connect
// and wants to know what's on the network. The faster we
// respond the faster we start to converge
// get node peers down to MaxDepth encoded in protobuf
msg := PeersToProto(n.node, MaxDepth)
// advertise yourself to the network
if err := n.sendTo("peer", NetworkChannel, peer, msg); err != nil {
log.Debugf("Network failed to advertise peers: %v", err)
}
// advertise all the routes when a new node has connected
if err := n.router.Solicit(); err != nil {
log.Debugf("Network failed to solicit routes: %s", err)
}
// specify that we're soliciting
select {
case n.solicited <- peer:
default:
// don't block
}
case "peer":
// mark the time the message has been received
now := time.Now()
pbNetPeer := &pbNet.Peer{}
if err := proto.Unmarshal(m.msg.Body, pbNetPeer); err != nil {
log.Debugf("Network tunnel [%s] peer unmarshal error: %v", NetworkChannel, err)
continue
}
// don't process your own messages
if pbNetPeer.Node.Id == n.options.Id {
continue
}
log.Debugf("Network received peer message from: %s %s", pbNetPeer.Node.Id, pbNetPeer.Node.Address)
peer := &node{
id: pbNetPeer.Node.Id,
address: pbNetPeer.Node.Address,
link: m.msg.Header["Micro-Link"],
peers: make(map[string]*node),
lastSeen: now,
}
// update peer links
if err := n.updatePeerLinks(peer); err != nil {
log.Debugf("Network failed updating peer links: %s", err)
}
if err := n.node.AddPeer(peer); err == nil {
// send a solicit message when discovering new peer
msg := &pbRtr.Solicit{
Id: n.options.Id,
}
// only solicit this peer
if err := n.sendTo("solicit", ControlChannel, peer, msg); err != nil {
log.Debugf("Network failed to send solicit message: %s", err)
}
continue
// we're expecting any error to be ErrPeerExists
} else if err != ErrPeerExists {
log.Debugf("Network got error adding peer %v", err)
continue
}
log.Tracef("Network peer exists, refreshing: %s", pbNetPeer.Node.Id)
// update lastSeen time for the peer
if err := n.RefreshPeer(pbNetPeer.Node.Id, peer.link, now); err != nil {
log.Debugf("Network failed refreshing peer %s: %v", pbNetPeer.Node.Id, err)
}
// NOTE: we don't unpack MaxDepth toplogy
peer = UnpackPeerTopology(pbNetPeer, now, MaxDepth-1)
log.Tracef("Network updating topology of node: %s", n.node.id)
if err := n.node.UpdatePeer(peer); err != nil {
log.Debugf("Network failed to update peers: %v", err)
}
// tell the connect loop that we've been discovered
// so it stops sending connect messages out
select {
case n.discovered <- true:
default:
// don't block here
}
case "close":
pbNetClose := &pbNet.Close{}
if err := proto.Unmarshal(m.msg.Body, pbNetClose); err != nil {
log.Debugf("Network tunnel [%s] close unmarshal error: %v", NetworkChannel, err)
continue
}
// don't process your own messages
if pbNetClose.Node.Id == n.options.Id {
continue
}
log.Debugf("Network received close message from: %s", pbNetClose.Node.Id)
peer := &node{
id: pbNetClose.Node.Id,
address: pbNetClose.Node.Address,
}
if err := n.DeletePeerNode(peer.id); err != nil {
log.Debugf("Network failed to delete node %s routes: %v", peer.id, err)
}
if err := n.prunePeerRoutes(peer); err != nil {
log.Debugf("Network failed pruning peer %s routes: %v", peer.id, err)
}
// delete peer from the peerLinks
n.Lock()
delete(n.peerLinks, pbNetClose.Node.Address)
n.Unlock()
}
case <-n.closed:
return
}
}
}
// pruneRoutes prunes routes return by given query
func (n *network) pruneRoutes(q ...router.QueryOption) error {
routes, err := n.router.Table().Query(q...)
if err != nil && err != router.ErrRouteNotFound {
return err
}
for _, route := range routes {
if err := n.router.Table().Delete(route); err != nil && err != router.ErrRouteNotFound {
return err
}
}
return nil
}
// pruneNodeRoutes prunes routes that were either originated by or routable via given node
func (n *network) prunePeerRoutes(peer *node) error {
// lookup all routes originated by router
q := []router.QueryOption{
router.QueryRouter(peer.id),
}
if err := n.pruneRoutes(q...); err != nil {
return err
}
// lookup all routes routable via gw
q = []router.QueryOption{
router.QueryGateway(peer.address),
}
if err := n.pruneRoutes(q...); err != nil {
return err
}
return nil
}
// manage the process of announcing to peers and prune any peer nodes that have not been
// seen for a period of time. Also removes all the routes either originated by or routable
//by the stale nodes. it also resolves nodes periodically and adds them to the tunnel
func (n *network) manage() {
announce := time.NewTicker(AnnounceTime)
defer announce.Stop()
prune := time.NewTicker(PruneTime)
defer prune.Stop()
resolve := time.NewTicker(ResolveTime)
defer resolve.Stop()
for {
select {
case <-n.closed:
return
case <-announce.C:
msg := PeersToProto(n.node, MaxDepth)
// advertise yourself to the network
if err := n.sendMsg("peer", NetworkChannel, msg); err != nil {
log.Debugf("Network failed to advertise peers: %v", err)
}
case <-prune.C:
pruned := n.PruneStalePeers(PruneTime)
for id, peer := range pruned {
log.Debugf("Network peer exceeded prune time: %s", id)
n.Lock()
delete(n.peerLinks, peer.address)
n.Unlock()
if err := n.prunePeerRoutes(peer); err != nil {
log.Debugf("Network failed pruning peer %s routes: %v", id, err)
}
}
// get a list of all routes
routes, err := n.options.Router.Table().List()
if err != nil {
log.Debugf("Network failed listing routes when pruning peers: %v", err)
continue
}
// collect all the router IDs in the routing table
routers := make(map[string]bool)
for _, route := range routes {
// check if its been processed
if _, ok := routers[route.Router]; ok {
continue
}
// mark as processed
routers[route.Router] = true
// if the router is NOT in our peer graph, delete all routes originated by it
if peer := n.node.GetPeerNode(route.Router); peer != nil {
continue
}
if err := n.pruneRoutes(router.QueryRouter(route.Router)); err != nil {
log.Debugf("Network failed deleting routes by %s: %v", route.Router, err)
}
}
case <-resolve.C:
n.initNodes(false)
}
}
}
func (n *network) sendConnect() {
// send connect message to NetworkChannel
// NOTE: in theory we could do this as soon as
// Dial to NetworkChannel succeeds, but instead
// we initialize all other node resources first
msg := &pbNet.Connect{
Node: &pbNet.Node{
Id: n.node.id,
Address: n.node.address,
},
}
if err := n.sendMsg("connect", NetworkChannel, msg); err != nil {
log.Debugf("Network failed to send connect message: %s", err)
}
}
// sendTo sends a message to a specific node as a one off.
// we need this because when links die, we have no discovery info,
// and sending to an existing multicast link doesn't immediately work
func (n *network) sendTo(method, channel string, peer *node, msg proto.Message) error {
body, err := proto.Marshal(msg)
if err != nil {
return err
}
c, err := n.tunnel.Dial(channel, tunnel.DialMode(tunnel.Multicast), tunnel.DialLink(peer.link))
if err != nil {
return err
}
defer c.Close()
log.Debugf("Network sending %s message from: %s to %s", method, n.options.Id, peer.id)
return c.Send(&transport.Message{
Header: map[string]string{
"Micro-Method": method,
"Micro-Peer": peer.id,
},
Body: body,
})
}
// sendMsg sends a message to the tunnel channel
func (n *network) sendMsg(method, channel string, msg proto.Message) error {
body, err := proto.Marshal(msg)
if err != nil {
return err
}
// check if the channel client is initialized
n.RLock()
client, ok := n.tunClient[channel]
if !ok || client == nil {
n.RUnlock()
return ErrClientNotFound
}
n.RUnlock()
log.Debugf("Network sending %s message from: %s", method, n.options.Id)
return client.Send(&transport.Message{
Header: map[string]string{
"Micro-Method": method,
},
Body: body,
})
}
// updatePeerLinks updates link for a given peer
func (n *network) updatePeerLinks(peer *node) error {
n.Lock()
defer n.Unlock()
linkId := peer.link
log.Tracef("Network looking up link %s in the peer links", linkId)
// lookup the peer link
var peerLink tunnel.Link
for _, link := range n.tunnel.Links() {
if link.Id() == linkId {
peerLink = link
break
}
}
if peerLink == nil {
return ErrPeerLinkNotFound
}
// if the peerLink is found in the returned links update peerLinks
log.Tracef("Network updating peer links for peer %s", peer.address)
// add peerLink to the peerLinks map
if link, ok := n.peerLinks[peer.address]; ok {
// if the existing has better Length then the new, replace it
if link.Length() < peerLink.Length() {
n.peerLinks[peer.address] = peerLink
}
} else {
n.peerLinks[peer.address] = peerLink
}
return nil
}
// connect will wait for a link to be established and send the connect
// message. We're trying to ensure convergence pretty quickly. So we want
// to hear back. In the case we become completely disconnected we'll
// connect again once a new link is established
func (n *network) connect() {
// discovered lets us know what we received a peer message back
var discovered bool
var attempts int
// our advertise address
loopback := n.server.Options().Advertise
// actual address
address := n.tunnel.Address()
for {
// connected is used to define if the link is connected
var connected bool
// check the links state
for _, link := range n.tunnel.Links() {
// skip loopback
if link.Loopback() {
continue
}
// if remote is ourselves
switch link.Remote() {
case loopback, address:
continue
}
if link.State() == "connected" {
connected = true
break
}
}
// if we're not connected wait
if !connected {
// reset discovered
discovered = false
// sleep for a second
time.Sleep(time.Second)
// now try again
continue
}
// we're connected but are we discovered?
if !discovered {
// recreate the clients because all the tunnel links are gone
// so we haven't send discovery beneath
if err := n.createClients(); err != nil {
log.Debugf("Failed to recreate network/control clients: %v", err)
continue
}
// send the connect message
n.sendConnect()
}
// check if we've been discovered
select {
case <-n.discovered:
discovered = true
attempts = 0
case <-n.closed:
return
case <-time.After(time.Second + backoff.Do(attempts)):
// we have to try again
attempts++
// reset attempts 5 == ~2mins
if attempts > 5 {
attempts = 0
}
}
}
}
// Connect connects the network
func (n *network) Connect() error {
n.Lock()
defer n.Unlock()
// connect network tunnel
if err := n.tunnel.Connect(); err != nil {
return err
}
// return if already connected
if n.connected {
// initialise the nodes
n.initNodes(false)
// send the connect message
go n.sendConnect()
return nil
}
// initialise the nodes
n.initNodes(true)
// set our internal node address
// if advertise address is not set
if len(n.options.Advertise) == 0 {
n.server.Init(server.Advertise(n.tunnel.Address()))
}
// listen on NetworkChannel
netListener, err := n.tunnel.Listen(
NetworkChannel,
tunnel.ListenMode(tunnel.Multicast),
tunnel.ListenTimeout(AnnounceTime*2),
)
if err != nil {
return err
}
// listen on ControlChannel
ctrlListener, err := n.tunnel.Listen(
ControlChannel,
tunnel.ListenMode(tunnel.Multicast),
tunnel.ListenTimeout(router.AdvertiseTableTick*2),
)
if err != nil {
return err
}
// dial into ControlChannel to send route adverts
ctrlClient, err := n.tunnel.Dial(ControlChannel, tunnel.DialMode(tunnel.Multicast))
if err != nil {
return err
}
n.tunClient[ControlChannel] = ctrlClient
// dial into NetworkChannel to send network messages
netClient, err := n.tunnel.Dial(NetworkChannel, tunnel.DialMode(tunnel.Multicast))
if err != nil {
return err
}
n.tunClient[NetworkChannel] = netClient
// create closed channel
n.closed = make(chan bool)
// start the router
if err := n.options.Router.Start(); err != nil {
return err
}
// start advertising routes
advertChan, err := n.options.Router.Advertise()
if err != nil {
return err
}
// start the server
if err := n.server.Start(); err != nil {
return err
}
// advertise service routes
go n.advertise(advertChan)
// listen to network messages
go n.processNetChan(netListener)
// accept and process routes
go n.processCtrlChan(ctrlListener)
// manage connection once links are established
go n.connect()
// resolve nodes, broadcast announcements and prune stale nodes
go n.manage()
// we're now connected
n.connected = true
return nil
}
func (n *network) close() error {
// stop the server
if err := n.server.Stop(); err != nil {
return err
}
// stop the router
if err := n.router.Stop(); err != nil {
return err
}
// close the tunnel
if err := n.tunnel.Close(); err != nil {
return err
}
return nil
}
// createClients is used to create new clients in the event we lose all the tunnels
func (n *network) createClients() error {
// dial into ControlChannel to send route adverts
ctrlClient, err := n.tunnel.Dial(ControlChannel, tunnel.DialMode(tunnel.Multicast))
if err != nil {
return err
}
// dial into NetworkChannel to send network messages
netClient, err := n.tunnel.Dial(NetworkChannel, tunnel.DialMode(tunnel.Multicast))
if err != nil {
return err
}
n.Lock()
defer n.Unlock()
// set the control client
c, ok := n.tunClient[ControlChannel]
if ok {
c.Close()
}
n.tunClient[ControlChannel] = ctrlClient
// set the network client
c, ok = n.tunClient[NetworkChannel]
if ok {
c.Close()
}
n.tunClient[NetworkChannel] = netClient
return nil
}
// Close closes network connection
func (n *network) Close() error {
n.Lock()
if !n.connected {
n.Unlock()
return nil
}
select {
case <-n.closed:
n.Unlock()
return nil
default:
// TODO: send close message to the network channel
close(n.closed)
// set connected to false
n.connected = false
// unlock the lock otherwise we'll deadlock sending the close
n.Unlock()
msg := &pbNet.Close{
Node: &pbNet.Node{
Id: n.node.id,
Address: n.node.address,
},
}
if err := n.sendMsg("close", NetworkChannel, msg); err != nil {
log.Debugf("Network failed to send close message: %s", err)
}
}
return n.close()
}
// Client returns network client
func (n *network) Client() client.Client {
return n.client
}
// Server returns network server
func (n *network) Server() server.Server {
return n.server
}