// Copyright 2017 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see . package adapters import ( "bytes" "context" "encoding/json" "errors" "fmt" "io" "net" "net/http" "os" "os/exec" "os/signal" "path/filepath" "strings" "sync" "syscall" "time" "github.com/docker/docker/pkg/reexec" "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/node" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/p2p/enode" "github.com/ethereum/go-ethereum/rpc" "github.com/gorilla/websocket" ) func init() { // Register a reexec function to start a simulation node when the current binary is // executed as "p2p-node" (rather than whatever the main() function would normally do). reexec.Register("p2p-node", execP2PNode) } // ExecAdapter is a NodeAdapter which runs simulation nodes by executing the current binary // as a child process. type ExecAdapter struct { // BaseDir is the directory under which the data directories for each // simulation node are created. BaseDir string nodes map[enode.ID]*ExecNode } // NewExecAdapter returns an ExecAdapter which stores node data in // subdirectories of the given base directory func NewExecAdapter(baseDir string) *ExecAdapter { return &ExecAdapter{ BaseDir: baseDir, nodes: make(map[enode.ID]*ExecNode), } } // Name returns the name of the adapter for logging purposes func (e *ExecAdapter) Name() string { return "exec-adapter" } // NewNode returns a new ExecNode using the given config func (e *ExecAdapter) NewNode(config *NodeConfig) (Node, error) { if len(config.Lifecycles) == 0 { return nil, errors.New("node must have at least one service lifecycle") } for _, service := range config.Lifecycles { if _, exists := lifecycleConstructorFuncs[service]; !exists { return nil, fmt.Errorf("unknown node service %q", service) } } // create the node directory using the first 12 characters of the ID // as Unix socket paths cannot be longer than 256 characters dir := filepath.Join(e.BaseDir, config.ID.String()[:12]) if err := os.Mkdir(dir, 0755); err != nil { return nil, fmt.Errorf("error creating node directory: %s", err) } err := config.initDummyEnode() if err != nil { return nil, err } // generate the config conf := &execNodeConfig{ Stack: node.DefaultConfig, Node: config, } if config.DataDir != "" { conf.Stack.DataDir = config.DataDir } else { conf.Stack.DataDir = filepath.Join(dir, "data") } // these parameters are crucial for execadapter node to run correctly conf.Stack.WSHost = "127.0.0.1" conf.Stack.WSPort = 0 conf.Stack.WSOrigins = []string{"*"} conf.Stack.WSExposeAll = true conf.Stack.P2P.EnableMsgEvents = config.EnableMsgEvents conf.Stack.P2P.NoDiscovery = true conf.Stack.P2P.NAT = nil conf.Stack.NoUSB = true // Listen on a localhost port, which we set when we // initialise NodeConfig (usually a random port) conf.Stack.P2P.ListenAddr = fmt.Sprintf(":%d", config.Port) node := &ExecNode{ ID: config.ID, Dir: dir, Config: conf, adapter: e, } node.newCmd = node.execCommand e.nodes[node.ID] = node return node, nil } // ExecNode starts a simulation node by exec'ing the current binary and // running the configured services type ExecNode struct { ID enode.ID Dir string Config *execNodeConfig Cmd *exec.Cmd Info *p2p.NodeInfo adapter *ExecAdapter client *rpc.Client wsAddr string newCmd func() *exec.Cmd } // Addr returns the node's enode URL func (n *ExecNode) Addr() []byte { if n.Info == nil { return nil } return []byte(n.Info.Enode) } // Client returns an rpc.Client which can be used to communicate with the // underlying services (it is set once the node has started) func (n *ExecNode) Client() (*rpc.Client, error) { return n.client, nil } // Start exec's the node passing the ID and service as command line arguments // and the node config encoded as JSON in an environment variable. func (n *ExecNode) Start(snapshots map[string][]byte) (err error) { if n.Cmd != nil { return errors.New("already started") } defer func() { if err != nil { n.Stop() } }() // encode a copy of the config containing the snapshot confCopy := *n.Config confCopy.Snapshots = snapshots confCopy.PeerAddrs = make(map[string]string) for id, node := range n.adapter.nodes { confCopy.PeerAddrs[id.String()] = node.wsAddr } confData, err := json.Marshal(confCopy) if err != nil { return fmt.Errorf("error generating node config: %s", err) } // start the one-shot server that waits for startup information ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second) defer cancel() statusURL, statusC := n.waitForStartupJSON(ctx) // start the node cmd := n.newCmd() cmd.Stdout = os.Stdout cmd.Stderr = os.Stderr cmd.Env = append(os.Environ(), envStatusURL+"="+statusURL, envNodeConfig+"="+string(confData), ) if err := cmd.Start(); err != nil { return fmt.Errorf("error starting node: %s", err) } n.Cmd = cmd // Wait for the node to start. status := <-statusC if status.Err != "" { return errors.New(status.Err) } client, err := rpc.DialWebsocket(ctx, status.WSEndpoint, "") if err != nil { return fmt.Errorf("can't connect to RPC server: %v", err) } // Node ready :) n.client = client n.wsAddr = status.WSEndpoint n.Info = status.NodeInfo return nil } // waitForStartupJSON runs a one-shot HTTP server to receive a startup report. func (n *ExecNode) waitForStartupJSON(ctx context.Context) (string, chan nodeStartupJSON) { var ( ch = make(chan nodeStartupJSON, 1) quitOnce sync.Once srv http.Server ) l, err := net.Listen("tcp", "127.0.0.1:0") if err != nil { ch <- nodeStartupJSON{Err: err.Error()} return "", ch } quit := func(status nodeStartupJSON) { quitOnce.Do(func() { l.Close() ch <- status }) } srv.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { var status nodeStartupJSON if err := json.NewDecoder(r.Body).Decode(&status); err != nil { status.Err = fmt.Sprintf("can't decode startup report: %v", err) } quit(status) }) // Run the HTTP server, but don't wait forever and shut it down // if the context is canceled. go srv.Serve(l) go func() { <-ctx.Done() quit(nodeStartupJSON{Err: "didn't get startup report"}) }() url := "http://" + l.Addr().String() return url, ch } // execCommand returns a command which runs the node locally by exec'ing // the current binary but setting argv[0] to "p2p-node" so that the child // runs execP2PNode func (n *ExecNode) execCommand() *exec.Cmd { return &exec.Cmd{ Path: reexec.Self(), Args: []string{"p2p-node", strings.Join(n.Config.Node.Lifecycles, ","), n.ID.String()}, } } // Stop stops the node by first sending SIGTERM and then SIGKILL if the node // doesn't stop within 5s func (n *ExecNode) Stop() error { if n.Cmd == nil { return nil } defer func() { n.Cmd = nil }() if n.client != nil { n.client.Close() n.client = nil n.wsAddr = "" n.Info = nil } if err := n.Cmd.Process.Signal(syscall.SIGTERM); err != nil { return n.Cmd.Process.Kill() } waitErr := make(chan error, 1) go func() { waitErr <- n.Cmd.Wait() }() select { case err := <-waitErr: return err case <-time.After(5 * time.Second): return n.Cmd.Process.Kill() } } // NodeInfo returns information about the node func (n *ExecNode) NodeInfo() *p2p.NodeInfo { info := &p2p.NodeInfo{ ID: n.ID.String(), } if n.client != nil { n.client.Call(&info, "admin_nodeInfo") } return info } // ServeRPC serves RPC requests over the given connection by dialling the // node's WebSocket address and joining the two connections func (n *ExecNode) ServeRPC(clientConn *websocket.Conn) error { conn, _, err := websocket.DefaultDialer.Dial(n.wsAddr, nil) if err != nil { return err } var wg sync.WaitGroup wg.Add(2) go wsCopy(&wg, conn, clientConn) go wsCopy(&wg, clientConn, conn) wg.Wait() conn.Close() return nil } func wsCopy(wg *sync.WaitGroup, src, dst *websocket.Conn) { defer wg.Done() for { msgType, r, err := src.NextReader() if err != nil { return } w, err := dst.NextWriter(msgType) if err != nil { return } if _, err = io.Copy(w, r); err != nil { return } } } // Snapshots creates snapshots of the services by calling the // simulation_snapshot RPC method func (n *ExecNode) Snapshots() (map[string][]byte, error) { if n.client == nil { return nil, errors.New("RPC not started") } var snapshots map[string][]byte return snapshots, n.client.Call(&snapshots, "simulation_snapshot") } // execNodeConfig is used to serialize the node configuration so it can be // passed to the child process as a JSON encoded environment variable type execNodeConfig struct { Stack node.Config `json:"stack"` Node *NodeConfig `json:"node"` Snapshots map[string][]byte `json:"snapshots,omitempty"` PeerAddrs map[string]string `json:"peer_addrs,omitempty"` } // execP2PNode starts a simulation node when the current binary is executed with // argv[0] being "p2p-node", reading the service / ID from argv[1] / argv[2] // and the node config from an environment variable. func execP2PNode() { glogger := log.NewGlogHandler(log.StreamHandler(os.Stderr, log.LogfmtFormat())) glogger.Verbosity(log.LvlInfo) log.Root().SetHandler(glogger) statusURL := os.Getenv(envStatusURL) if statusURL == "" { log.Crit("missing " + envStatusURL) } // Start the node and gather startup report. var status nodeStartupJSON stack, stackErr := startExecNodeStack() if stackErr != nil { status.Err = stackErr.Error() } else { status.WSEndpoint = "ws://" + stack.WSEndpoint() status.NodeInfo = stack.Server().NodeInfo() } // Send status to the host. statusJSON, _ := json.Marshal(status) if _, err := http.Post(statusURL, "application/json", bytes.NewReader(statusJSON)); err != nil { log.Crit("Can't post startup info", "url", statusURL, "err", err) } if stackErr != nil { os.Exit(1) } // Stop the stack if we get a SIGTERM signal. go func() { sigc := make(chan os.Signal, 1) signal.Notify(sigc, syscall.SIGTERM) defer signal.Stop(sigc) <-sigc log.Info("Received SIGTERM, shutting down...") stack.Close() }() stack.Wait() // Wait for the stack to exit. } func startExecNodeStack() (*node.Node, error) { // read the services from argv serviceNames := strings.Split(os.Args[1], ",") // decode the config confEnv := os.Getenv(envNodeConfig) if confEnv == "" { return nil, fmt.Errorf("missing " + envNodeConfig) } var conf execNodeConfig if err := json.Unmarshal([]byte(confEnv), &conf); err != nil { return nil, fmt.Errorf("error decoding %s: %v", envNodeConfig, err) } // create enode record nodeTcpConn, _ := net.ResolveTCPAddr("tcp", conf.Stack.P2P.ListenAddr) if nodeTcpConn.IP == nil { nodeTcpConn.IP = net.IPv4(127, 0, 0, 1) } conf.Node.initEnode(nodeTcpConn.IP, nodeTcpConn.Port, nodeTcpConn.Port) conf.Stack.P2P.PrivateKey = conf.Node.PrivateKey conf.Stack.Logger = log.New("node.id", conf.Node.ID.String()) // initialize the devp2p stack stack, err := node.New(&conf.Stack) if err != nil { return nil, fmt.Errorf("error creating node stack: %v", err) } // Register the services, collecting them into a map so they can // be accessed by the snapshot API. services := make(map[string]node.Lifecycle, len(serviceNames)) for _, name := range serviceNames { lifecycleFunc, exists := lifecycleConstructorFuncs[name] if !exists { return nil, fmt.Errorf("unknown node service %q", err) } ctx := &ServiceContext{ RPCDialer: &wsRPCDialer{addrs: conf.PeerAddrs}, Config: conf.Node, } if conf.Snapshots != nil { ctx.Snapshot = conf.Snapshots[name] } service, err := lifecycleFunc(ctx, stack) if err != nil { return nil, err } services[name] = service stack.RegisterLifecycle(service) } // Add the snapshot API. stack.RegisterAPIs([]rpc.API{{ Namespace: "simulation", Version: "1.0", Service: SnapshotAPI{services}, }}) if err = stack.Start(); err != nil { err = fmt.Errorf("error starting stack: %v", err) } return stack, err } const ( envStatusURL = "_P2P_STATUS_URL" envNodeConfig = "_P2P_NODE_CONFIG" ) // nodeStartupJSON is sent to the simulation host after startup. type nodeStartupJSON struct { Err string WSEndpoint string NodeInfo *p2p.NodeInfo } // SnapshotAPI provides an RPC method to create snapshots of services type SnapshotAPI struct { services map[string]node.Lifecycle } func (api SnapshotAPI) Snapshot() (map[string][]byte, error) { snapshots := make(map[string][]byte) for name, service := range api.services { if s, ok := service.(interface { Snapshot() ([]byte, error) }); ok { snap, err := s.Snapshot() if err != nil { return nil, err } snapshots[name] = snap } } return snapshots, nil } type wsRPCDialer struct { addrs map[string]string } // DialRPC implements the RPCDialer interface by creating a WebSocket RPC // client of the given node func (w *wsRPCDialer) DialRPC(id enode.ID) (*rpc.Client, error) { addr, ok := w.addrs[id.String()] if !ok { return nil, fmt.Errorf("unknown node: %s", id) } return rpc.DialWebsocket(context.Background(), addr, "http://localhost") }