package main import ( "encoding/json" "fmt" "math" "time" em "github.com/tendermint/go-event-meter" events "github.com/tendermint/go-events" rpc_client "github.com/tendermint/go-rpc/client" tmtypes "github.com/tendermint/tendermint/types" crypto "github.com/tendermint/go-crypto" wire "github.com/tendermint/go-wire" ctypes "github.com/tendermint/tendermint/rpc/core/types" ) const maxRestarts = 25 type Node struct { rpcAddr string IsValidator bool `json:"is_validator"` // validator or non-validator? pubKey crypto.PubKey `json:"pub_key"` Name string `json:"name"` Online bool `json:"online"` Height uint64 `json:"height"` BlockLatency float64 `json:"block_latency" wire:"unsafe"` // ms, interval between block commits // em holds the ws connection. Each eventMeter callback is called in a separate go-routine. em eventMeter // rpcClient is an http client for making RPC calls to TM rpcClient *rpc_client.ClientURI blockCh chan<- tmtypes.Header blockLatencyCh chan<- float64 disconnectCh chan<- bool quit chan struct{} } func NewNode(rpcAddr string) *Node { em := em.NewEventMeter(rpcAddr, UnmarshalEvent) return NewNodeWithEventMeter(rpcAddr, em) } func NewNodeWithEventMeter(rpcAddr string, em eventMeter) *Node { return &Node{ rpcAddr: rpcAddr, em: em, rpcClient: rpc_client.NewClientURI(rpcAddr), Name: rpcAddr, quit: make(chan struct{}), } } func (n *Node) SendBlocksTo(ch chan<- tmtypes.Header) { n.blockCh = ch } func (n *Node) SendBlockLatenciesTo(ch chan<- float64) { n.blockLatencyCh = ch } func (n *Node) NotifyAboutDisconnects(ch chan<- bool) { n.disconnectCh = ch } func (n *Node) Start() error { if _, err := n.em.Start(); err != nil { return err } n.em.RegisterLatencyCallback(latencyCallback(n)) n.em.Subscribe(tmtypes.EventStringNewBlockHeader(), newBlockCallback(n)) n.em.RegisterDisconnectCallback(disconnectCallback(n)) n.Online = true go n.checkIsValidator() return nil } func (n *Node) Stop() { n.Online = false n.em.RegisterLatencyCallback(nil) n.em.Unsubscribe(tmtypes.EventStringNewBlockHeader()) n.em.RegisterDisconnectCallback(nil) // FIXME stop blocks at event_meter.go:140 // n.em.Stop() close(n.quit) } // implements eventmeter.EventCallbackFunc func newBlockCallback(n *Node) em.EventCallbackFunc { return func(metric *em.EventMetric, data events.EventData) { block := data.(tmtypes.EventDataNewBlockHeader).Header n.Height = uint64(block.Height) if n.blockCh != nil { n.blockCh <- *block } } } // implements eventmeter.EventLatencyFunc func latencyCallback(n *Node) em.LatencyCallbackFunc { return func(latency float64) { n.BlockLatency = latency / 1000000.0 // ns to ms if n.blockLatencyCh != nil { n.blockLatencyCh <- latency } } } // implements eventmeter.DisconnectCallbackFunc func disconnectCallback(n *Node) em.DisconnectCallbackFunc { return func() { n.Online = false if n.disconnectCh != nil { n.disconnectCh <- true } if err := n.RestartBackOff(); err != nil { log.Error(err.Error()) } else { n.Online = true if n.disconnectCh != nil { n.disconnectCh <- false } } } } func (n *Node) RestartBackOff() error { attempt := 0 for { d := time.Duration(math.Exp2(float64(attempt))) time.Sleep(d * time.Second) if err := n.Start(); err != nil { log.Debug("Can't connect to node %v due to %v", n, err) } else { // TODO: authenticate pubkey return nil } attempt++ if attempt > maxRestarts { return fmt.Errorf("Reached max restarts for node %v", n) } } } func (n *Node) NumValidators() (height uint64, num int, err error) { height, vals, err := n.validators() if err != nil { return 0, 0, err } return height, len(vals), nil } func (n *Node) validators() (height uint64, validators []*tmtypes.Validator, err error) { var result ctypes.TMResult if _, err = n.rpcClient.Call("validators", nil, &result); err != nil { return 0, make([]*tmtypes.Validator, 0), err } vals := result.(*ctypes.ResultValidators) return uint64(vals.BlockHeight), vals.Validators, nil } func (n *Node) checkIsValidator() { for { select { case <-n.quit: return case <-time.After(5 * time.Second): _, validators, err := n.validators() if err == nil { for _, v := range validators { key, err := n.getPubKey() if err == nil && v.PubKey == key { n.IsValidator = true } } } else { log.Debug(err.Error()) } } } } func (n *Node) getPubKey() (crypto.PubKey, error) { if n.pubKey != nil { return n.pubKey, nil } var result ctypes.TMResult _, err := n.rpcClient.Call("status", nil, &result) if err != nil { return nil, err } status := result.(*ctypes.ResultStatus) n.pubKey = status.PubKey return n.pubKey, nil } type eventMeter interface { Start() (bool, error) Stop() bool RegisterLatencyCallback(em.LatencyCallbackFunc) RegisterDisconnectCallback(em.DisconnectCallbackFunc) Subscribe(string, em.EventCallbackFunc) error Unsubscribe(string) error } // UnmarshalEvent unmarshals a json event func UnmarshalEvent(b json.RawMessage) (string, events.EventData, error) { var err error result := new(ctypes.TMResult) wire.ReadJSONPtr(result, b, &err) if err != nil { return "", nil, err } event, ok := (*result).(*ctypes.ResultEvent) if !ok { return "", nil, nil // TODO: handle non-event messages (ie. return from subscribe/unsubscribe) // fmt.Errorf("Result is not type *ctypes.ResultEvent. Got %v", reflect.TypeOf(*result)) } return event.Name, event.Data, nil }