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// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package lsprpc implements a jsonrpc2.StreamServer that may be used to
// serve the LSP on a jsonrpc2 channel.
package lsprpc
import (
"context"
"encoding/json"
"fmt"
"log"
"net"
"os"
"strconv"
"sync/atomic"
"time"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/gocommand"
"golang.org/x/tools/internal/jsonrpc2"
"golang.org/x/tools/internal/lsp"
"golang.org/x/tools/internal/lsp/cache"
"golang.org/x/tools/internal/lsp/debug"
"golang.org/x/tools/internal/lsp/debug/tag"
"golang.org/x/tools/internal/lsp/protocol"
errors "golang.org/x/xerrors"
)
// AutoNetwork is the pseudo network type used to signal that gopls should use
// automatic discovery to resolve a remote address.
const AutoNetwork = "auto"
// Unique identifiers for client/server.
var serverIndex int64
// The StreamServer type is a jsonrpc2.StreamServer that handles incoming
// streams as a new LSP session, using a shared cache.
type StreamServer struct {
cache *cache.Cache
// daemon controls whether or not to log new connections.
daemon bool
// serverForTest may be set to a test fake for testing.
serverForTest protocol.Server
}
// NewStreamServer creates a StreamServer using the shared cache. If
// withTelemetry is true, each session is instrumented with telemetry that
// records RPC statistics.
func NewStreamServer(cache *cache.Cache, daemon bool) *StreamServer {
return &StreamServer{cache: cache, daemon: daemon}
}
// ServeStream implements the jsonrpc2.StreamServer interface, by handling
// incoming streams using a new lsp server.
func (s *StreamServer) ServeStream(ctx context.Context, conn jsonrpc2.Conn) error {
client := protocol.ClientDispatcher(conn)
session := s.cache.NewSession(ctx)
server := s.serverForTest
if server == nil {
server = lsp.NewServer(session, client)
}
// Clients may or may not send a shutdown message. Make sure the server is
// shut down.
// TODO(rFindley): this shutdown should perhaps be on a disconnected context.
defer func() {
if err := server.Shutdown(ctx); err != nil {
event.Error(ctx, "error shutting down", err)
}
}()
executable, err := os.Executable()
if err != nil {
log.Printf("error getting gopls path: %v", err)
executable = ""
}
ctx = protocol.WithClient(ctx, client)
conn.Go(ctx,
protocol.Handlers(
handshaker(session, executable, s.daemon,
protocol.ServerHandler(server,
jsonrpc2.MethodNotFound))))
if s.daemon {
log.Printf("Session %s: connected", session.ID())
defer log.Printf("Session %s: exited", session.ID())
}
<-conn.Done()
return conn.Err()
}
// A Forwarder is a jsonrpc2.StreamServer that handles an LSP stream by
// forwarding it to a remote. This is used when the gopls process started by
// the editor is in the `-remote` mode, which means it finds and connects to a
// separate gopls daemon. In these cases, we still want the forwarder gopls to
// be instrumented with telemetry, and want to be able to in some cases hijack
// the jsonrpc2 connection with the daemon.
type Forwarder struct {
network, addr string
// goplsPath is the path to the current executing gopls binary.
goplsPath string
// configuration for the auto-started gopls remote.
remoteConfig remoteConfig
}
type remoteConfig struct {
debug string
listenTimeout time.Duration
logfile string
}
// A RemoteOption configures the behavior of the auto-started remote.
type RemoteOption interface {
set(*remoteConfig)
}
// RemoteDebugAddress configures the address used by the auto-started Gopls daemon
// for serving debug information.
type RemoteDebugAddress string
func (d RemoteDebugAddress) set(cfg *remoteConfig) {
cfg.debug = string(d)
}
// RemoteListenTimeout configures the amount of time the auto-started gopls
// daemon will wait with no client connections before shutting down.
type RemoteListenTimeout time.Duration
func (d RemoteListenTimeout) set(cfg *remoteConfig) {
cfg.listenTimeout = time.Duration(d)
}
// RemoteLogfile configures the logfile location for the auto-started gopls
// daemon.
type RemoteLogfile string
func (l RemoteLogfile) set(cfg *remoteConfig) {
cfg.logfile = string(l)
}
func defaultRemoteConfig() remoteConfig {
return remoteConfig{
listenTimeout: 1 * time.Minute,
}
}
// NewForwarder creates a new Forwarder, ready to forward connections to the
// remote server specified by network and addr.
func NewForwarder(network, addr string, opts ...RemoteOption) *Forwarder {
gp, err := os.Executable()
if err != nil {
log.Printf("error getting gopls path for forwarder: %v", err)
gp = ""
}
rcfg := defaultRemoteConfig()
for _, opt := range opts {
opt.set(&rcfg)
}
fwd := &Forwarder{
network: network,
addr: addr,
goplsPath: gp,
remoteConfig: rcfg,
}
return fwd
}
// QueryServerState queries the server state of the current server.
func QueryServerState(ctx context.Context, network, address string) (*ServerState, error) {
if network == AutoNetwork {
gp, err := os.Executable()
if err != nil {
return nil, errors.Errorf("getting gopls path: %w", err)
}
network, address = autoNetworkAddress(gp, address)
}
netConn, err := net.DialTimeout(network, address, 5*time.Second)
if err != nil {
return nil, errors.Errorf("dialing remote: %w", err)
}
serverConn := jsonrpc2.NewConn(jsonrpc2.NewHeaderStream(netConn))
serverConn.Go(ctx, jsonrpc2.MethodNotFound)
var state ServerState
if err := protocol.Call(ctx, serverConn, sessionsMethod, nil, &state); err != nil {
return nil, errors.Errorf("querying server state: %w", err)
}
return &state, nil
}
// ServeStream dials the forwarder remote and binds the remote to serve the LSP
// on the incoming stream.
func (f *Forwarder) ServeStream(ctx context.Context, clientConn jsonrpc2.Conn) error {
client := protocol.ClientDispatcher(clientConn)
netConn, err := f.connectToRemote(ctx)
if err != nil {
return errors.Errorf("forwarder: connecting to remote: %w", err)
}
serverConn := jsonrpc2.NewConn(jsonrpc2.NewHeaderStream(netConn))
server := protocol.ServerDispatcher(serverConn)
// Forward between connections.
serverConn.Go(ctx,
protocol.Handlers(
protocol.ClientHandler(client,
jsonrpc2.MethodNotFound)))
// Don't run the clientConn yet, so that we can complete the handshake before
// processing any client messages.
// Do a handshake with the server instance to exchange debug information.
index := atomic.AddInt64(&serverIndex, 1)
serverID := strconv.FormatInt(index, 10)
var (
hreq = handshakeRequest{
ServerID: serverID,
GoplsPath: f.goplsPath,
}
hresp handshakeResponse
)
if di := debug.GetInstance(ctx); di != nil {
hreq.Logfile = di.Logfile
hreq.DebugAddr = di.ListenedDebugAddress
}
if err := protocol.Call(ctx, serverConn, handshakeMethod, hreq, &hresp); err != nil {
// TODO(rfindley): at some point in the future we should return an error
// here. Handshakes have become functional in nature.
event.Error(ctx, "forwarder: gopls handshake failed", err)
}
if hresp.GoplsPath != f.goplsPath {
event.Error(ctx, "", fmt.Errorf("forwarder: gopls path mismatch: forwarder is %q, remote is %q", f.goplsPath, hresp.GoplsPath))
}
event.Log(ctx, "New server",
tag.NewServer.Of(serverID),
tag.Logfile.Of(hresp.Logfile),
tag.DebugAddress.Of(hresp.DebugAddr),
tag.GoplsPath.Of(hresp.GoplsPath),
tag.ClientID.Of(hresp.SessionID),
)
clientConn.Go(ctx,
protocol.Handlers(
forwarderHandler(
protocol.ServerHandler(server,
jsonrpc2.MethodNotFound))))
select {
case <-serverConn.Done():
clientConn.Close()
case <-clientConn.Done():
serverConn.Close()
}
err = nil
if serverConn.Err() != nil {
err = errors.Errorf("remote disconnected: %v", err)
} else if clientConn.Err() != nil {
err = errors.Errorf("client disconnected: %v", err)
}
event.Log(ctx, fmt.Sprintf("forwarder: exited with error: %v", err))
return err
}
func (f *Forwarder) connectToRemote(ctx context.Context) (net.Conn, error) {
return connectToRemote(ctx, f.network, f.addr, f.goplsPath, f.remoteConfig)
}
func ConnectToRemote(ctx context.Context, network, addr string, opts ...RemoteOption) (net.Conn, error) {
rcfg := defaultRemoteConfig()
for _, opt := range opts {
opt.set(&rcfg)
}
// This is not strictly necessary, as it won't be used if not connecting to
// the 'auto' remote.
goplsPath, err := os.Executable()
if err != nil {
return nil, fmt.Errorf("unable to resolve gopls path: %v", err)
}
return connectToRemote(ctx, network, addr, goplsPath, rcfg)
}
func connectToRemote(ctx context.Context, inNetwork, inAddr, goplsPath string, rcfg remoteConfig) (net.Conn, error) {
var (
netConn net.Conn
err error
network, address = inNetwork, inAddr
)
if inNetwork == AutoNetwork {
// f.network is overloaded to support a concept of 'automatic' addresses,
// which signals that the gopls remote address should be automatically
// derived.
// So we need to resolve a real network and address here.
network, address = autoNetworkAddress(goplsPath, inAddr)
}
// Attempt to verify that we own the remote. This is imperfect, but if we can
// determine that the remote is owned by a different user, we should fail.
ok, err := verifyRemoteOwnership(network, address)
if err != nil {
// If the ownership check itself failed, we fail open but log an error to
// the user.
event.Error(ctx, "unable to check daemon socket owner, failing open", err)
} else if !ok {
// We successfully checked that the socket is not owned by us, we fail
// closed.
return nil, fmt.Errorf("socket %q is owned by a different user", address)
}
const dialTimeout = 1 * time.Second
// Try dialing our remote once, in case it is already running.
netConn, err = net.DialTimeout(network, address, dialTimeout)
if err == nil {
return netConn, nil
}
// If our remote is on the 'auto' network, start it if it doesn't exist.
if inNetwork == AutoNetwork {
if goplsPath == "" {
return nil, fmt.Errorf("cannot auto-start remote: gopls path is unknown")
}
if network == "unix" {
// Sometimes the socketfile isn't properly cleaned up when gopls shuts
// down. Since we have already tried and failed to dial this address, it
// should *usually* be safe to remove the socket before binding to the
// address.
// TODO(rfindley): there is probably a race here if multiple gopls
// instances are simultaneously starting up.
if _, err := os.Stat(address); err == nil {
if err := os.Remove(address); err != nil {
return nil, errors.Errorf("removing remote socket file: %w", err)
}
}
}
args := []string{"serve",
"-listen", fmt.Sprintf(`%s;%s`, network, address),
"-listen.timeout", rcfg.listenTimeout.String(),
}
if rcfg.logfile != "" {
args = append(args, "-logfile", rcfg.logfile)
}
if rcfg.debug != "" {
args = append(args, "-debug", rcfg.debug)
}
if err := startRemote(goplsPath, args...); err != nil {
return nil, errors.Errorf("startRemote(%q, %v): %w", goplsPath, args, err)
}
}
const retries = 5
// It can take some time for the newly started server to bind to our address,
// so we retry for a bit.
for retry := 0; retry < retries; retry++ {
startDial := time.Now()
netConn, err = net.DialTimeout(network, address, dialTimeout)
if err == nil {
return netConn, nil
}
event.Log(ctx, fmt.Sprintf("failed attempt #%d to connect to remote: %v\n", retry+2, err))
// In case our failure was a fast-failure, ensure we wait at least
// f.dialTimeout before trying again.
if retry != retries-1 {
time.Sleep(dialTimeout - time.Since(startDial))
}
}
return nil, errors.Errorf("dialing remote: %w", err)
}
// forwarderHandler intercepts 'exit' messages to prevent the shared gopls
// instance from exiting. In the future it may also intercept 'shutdown' to
// provide more graceful shutdown of the client connection.
func forwarderHandler(handler jsonrpc2.Handler) jsonrpc2.Handler {
return func(ctx context.Context, reply jsonrpc2.Replier, r jsonrpc2.Request) error {
// The gopls workspace environment defaults to the process environment in
// which gopls daemon was started. To avoid discrepancies in Go environment
// between the editor and daemon, inject any unset variables in `go env`
// into the options sent by initialize.
//
// See also golang.org/issue/37830.
if r.Method() == "initialize" {
if newr, err := addGoEnvToInitializeRequest(ctx, r); err == nil {
r = newr
} else {
log.Printf("unable to add local env to initialize request: %v", err)
}
}
return handler(ctx, reply, r)
}
}
// addGoEnvToInitializeRequest builds a new initialize request in which we set
// any environment variables output by `go env` and not already present in the
// request.
//
// It returns an error if r is not an initialize requst, or is otherwise
// malformed.
func addGoEnvToInitializeRequest(ctx context.Context, r jsonrpc2.Request) (jsonrpc2.Request, error) {
var params protocol.ParamInitialize
if err := json.Unmarshal(r.Params(), &params); err != nil {
return nil, err
}
var opts map[string]interface{}
switch v := params.InitializationOptions.(type) {
case nil:
opts = make(map[string]interface{})
case map[string]interface{}:
opts = v
default:
return nil, fmt.Errorf("unexpected type for InitializationOptions: %T", v)
}
envOpt, ok := opts["env"]
if !ok {
envOpt = make(map[string]interface{})
}
env, ok := envOpt.(map[string]interface{})
if !ok {
return nil, fmt.Errorf(`env option is %T, expected a map`, envOpt)
}
goenv, err := getGoEnv(ctx, env)
if err != nil {
return nil, err
}
for govar, value := range goenv {
env[govar] = value
}
opts["env"] = env
params.InitializationOptions = opts
call, ok := r.(*jsonrpc2.Call)
if !ok {
return nil, fmt.Errorf("%T is not a *jsonrpc2.Call", r)
}
return jsonrpc2.NewCall(call.ID(), "initialize", params)
}
func getGoEnv(ctx context.Context, env map[string]interface{}) (map[string]string, error) {
var runEnv []string
for k, v := range env {
runEnv = append(runEnv, fmt.Sprintf("%s=%s", k, v))
}
runner := gocommand.Runner{}
output, err := runner.Run(ctx, gocommand.Invocation{
Verb: "env",
Args: []string{"-json"},
Env: runEnv,
})
if err != nil {
return nil, err
}
envmap := make(map[string]string)
if err := json.Unmarshal(output.Bytes(), &envmap); err != nil {
return nil, err
}
return envmap, nil
}
// A handshakeRequest identifies a client to the LSP server.
type handshakeRequest struct {
// ServerID is the ID of the server on the client. This should usually be 0.
ServerID string `json:"serverID"`
// Logfile is the location of the clients log file.
Logfile string `json:"logfile"`
// DebugAddr is the client debug address.
DebugAddr string `json:"debugAddr"`
// GoplsPath is the path to the Gopls binary running the current client
// process.
GoplsPath string `json:"goplsPath"`
}
// A handshakeResponse is returned by the LSP server to tell the LSP client
// information about its session.
type handshakeResponse struct {
// SessionID is the server session associated with the client.
SessionID string `json:"sessionID"`
// Logfile is the location of the server logs.
Logfile string `json:"logfile"`
// DebugAddr is the server debug address.
DebugAddr string `json:"debugAddr"`
// GoplsPath is the path to the Gopls binary running the current server
// process.
GoplsPath string `json:"goplsPath"`
}
// ClientSession identifies a current client LSP session on the server. Note
// that it looks similar to handshakeResposne, but in fact 'Logfile' and
// 'DebugAddr' now refer to the client.
type ClientSession struct {
SessionID string `json:"sessionID"`
Logfile string `json:"logfile"`
DebugAddr string `json:"debugAddr"`
}
// ServerState holds information about the gopls daemon process, including its
// debug information and debug information of all of its current connected
// clients.
type ServerState struct {
Logfile string `json:"logfile"`
DebugAddr string `json:"debugAddr"`
GoplsPath string `json:"goplsPath"`
CurrentClientID string `json:"currentClientID"`
Clients []ClientSession `json:"clients"`
}
const (
handshakeMethod = "gopls/handshake"
sessionsMethod = "gopls/sessions"
)
func handshaker(session *cache.Session, goplsPath string, logHandshakes bool, handler jsonrpc2.Handler) jsonrpc2.Handler {
return func(ctx context.Context, reply jsonrpc2.Replier, r jsonrpc2.Request) error {
switch r.Method() {
case handshakeMethod:
// We log.Printf in this handler, rather than event.Log when we want logs
// to go to the daemon log rather than being reflected back to the
// client.
var req handshakeRequest
if err := json.Unmarshal(r.Params(), &req); err != nil {
if logHandshakes {
log.Printf("Error processing handshake for session %s: %v", session.ID(), err)
}
sendError(ctx, reply, err)
return nil
}
if logHandshakes {
log.Printf("Session %s: got handshake. Logfile: %q, Debug addr: %q", session.ID(), req.Logfile, req.DebugAddr)
}
event.Log(ctx, "Handshake session update",
cache.KeyUpdateSession.Of(session),
tag.DebugAddress.Of(req.DebugAddr),
tag.Logfile.Of(req.Logfile),
tag.ServerID.Of(req.ServerID),
tag.GoplsPath.Of(req.GoplsPath),
)
resp := handshakeResponse{
SessionID: session.ID(),
GoplsPath: goplsPath,
}
if di := debug.GetInstance(ctx); di != nil {
resp.Logfile = di.Logfile
resp.DebugAddr = di.ListenedDebugAddress
}
return reply(ctx, resp, nil)
case sessionsMethod:
resp := ServerState{
GoplsPath: goplsPath,
CurrentClientID: session.ID(),
}
if di := debug.GetInstance(ctx); di != nil {
resp.Logfile = di.Logfile
resp.DebugAddr = di.ListenedDebugAddress
for _, c := range di.State.Clients() {
resp.Clients = append(resp.Clients, ClientSession{
SessionID: c.Session.ID(),
Logfile: c.Logfile,
DebugAddr: c.DebugAddress,
})
}
}
return reply(ctx, resp, nil)
}
return handler(ctx, reply, r)
}
}
func sendError(ctx context.Context, reply jsonrpc2.Replier, err error) {
err = errors.Errorf("%v: %w", err, jsonrpc2.ErrParse)
if err := reply(ctx, nil, err); err != nil {
event.Error(ctx, "", err)
}
}