package main import ( "bytes" "crypto/rand" "encoding/base64" "encoding/gob" "encoding/json" "errors" "fmt" "io/ioutil" "net" "os" "path" "time" "github.com/mattn/go-isatty" "github.com/hashicorp/errwrap" "github.com/hashicorp/go-multierror" "github.com/hashicorp/memberlist" "github.com/sirupsen/logrus" ) // ClusterState keeps track of information needed to rejoin the cluster type ClusterState struct { ClusterKey []byte Nodes []node } type cluster struct { localName string // used to avoid LocalNode(); should not change ml *memberlist.Memberlist wg *wgState state *ClusterState events chan memberlist.NodeEvent } const statePath = "/var/lib/wesher/state.json" func newCluster(config *config, wg *wgState) (*cluster, error) { clusterKey := config.ClusterKey state := loadState() if len(clusterKey) == 0 { clusterKey = state.ClusterKey } if len(clusterKey) == 0 { clusterKey = make([]byte, clusterKeyLen) _, err := rand.Read(clusterKey) if err != nil { return nil, err } // TODO: refactor this into subcommand ("showkey"?) if isatty.IsTerminal(os.Stdout.Fd()) { fmt.Printf("new cluster key generated: %s\n", base64.StdEncoding.EncodeToString(clusterKey)) } } state.ClusterKey = clusterKey mlConfig := memberlist.DefaultWANConfig() mlConfig.LogOutput = logrus.StandardLogger().WriterLevel(logrus.DebugLevel) mlConfig.SecretKey = clusterKey mlConfig.BindAddr = config.BindAddr mlConfig.BindPort = config.ClusterPort mlConfig.AdvertisePort = config.ClusterPort if config.UseIPAsName && config.BindAddr != "0.0.0.0" { mlConfig.Name = config.BindAddr } ml, err := memberlist.Create(mlConfig) if err != nil { return nil, err } cluster := cluster{ localName: ml.LocalNode().Name, ml: ml, wg: wg, events: make(chan memberlist.NodeEvent, 1), state: state, } mlConfig.Conflict = &cluster mlConfig.Events = &memberlist.ChannelEventDelegate{Ch: cluster.events} mlConfig.Delegate = &cluster wg.assignIP((*net.IPNet)(config.OverlayNet), cluster.localName) ml.UpdateNode(1 * time.Second) // we currently do not update after creation return &cluster, nil } func (c *cluster) NotifyConflict(node, other *memberlist.Node) { logrus.Errorf("node name conflict detected: %s", other.Name) } // none if these are used func (c *cluster) NotifyMsg([]byte) {} func (c *cluster) GetBroadcasts(overhead, limit int) [][]byte { return nil } func (c *cluster) LocalState(join bool) []byte { return nil } func (c *cluster) MergeRemoteState(buf []byte, join bool) {} type nodeMeta struct { OverlayAddr net.IP PubKey string } func (c *cluster) NodeMeta(limit int) []byte { buf := &bytes.Buffer{} if err := gob.NewEncoder(buf).Encode(nodeMeta{ OverlayAddr: c.wg.OverlayAddr, PubKey: c.wg.PubKey, }); err != nil { logrus.Errorf("could not encode local state: %s", err) return nil } if buf.Len() > limit { logrus.Errorf("could not fit node metadata into %d bytes", limit) return nil } return buf.Bytes() } func decodeNodeMeta(b []byte) (nodeMeta, error) { nm := nodeMeta{} if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&nm); err != nil { return nm, errwrap.Wrapf("could not decode: {{err}}", err) } return nm, nil } func (c *cluster) join(addrs []string) error { if len(addrs) == 0 { for _, n := range c.state.Nodes { addrs = append(addrs, n.Addr.String()) } } if _, err := c.ml.Join(addrs); err != nil { return err } else if len(addrs) > 0 && c.ml.NumMembers() < 2 { return errors.New("could not join to any of the provided addresses") } return nil } func (c *cluster) leave() { c.saveState() c.ml.Leave(10 * time.Second) c.ml.Shutdown() // ignore errors } func (c *cluster) members() (<-chan []node, <-chan error) { changes := make(chan []node) errc := make(chan error, 1) go func() { for { event := <-c.events if event.Node.Name == c.localName { // ignore events about ourselves continue } switch event.Event { case memberlist.NodeJoin: logrus.Infof("node %s joined", event.Node) case memberlist.NodeUpdate: logrus.Infof("node %s updated", event.Node) case memberlist.NodeLeave: logrus.Infof("node %s left", event.Node) } nodes := make([]node, 0) var errs error for _, n := range c.ml.Members() { if n.Name == c.localName { continue } meta, err := decodeNodeMeta(n.Meta) if err != nil { errs = multierror.Append(errs, err) continue } nodes = append(nodes, node{ Name: n.Name, Addr: n.Addr, nodeMeta: meta, }) } c.state.Nodes = nodes changes <- nodes if errs != nil { errc <- errs } c.saveState() } }() return changes, errc } type node struct { Name string Addr net.IP nodeMeta } func (n *node) String() string { return n.Addr.String() } func (c *cluster) saveState() error { if err := os.MkdirAll(path.Dir(statePath), 0700); err != nil { return err } stateOut, err := json.MarshalIndent(c.state, "", " ") if err != nil { return err } return ioutil.WriteFile(statePath, stateOut, 0700) } func loadState() *ClusterState { content, err := ioutil.ReadFile(statePath) if err != nil { if !os.IsNotExist(err) { logrus.Warnf("could not open state in %s: %s", statePath, err) } return &ClusterState{} } s := &ClusterState{} if err := json.Unmarshal(content, s); err != nil { logrus.Warnf("could not decode state: %s", err) return &ClusterState{} // avoid partially unmarshalled content } return s }