plugeth/node/rpcstack.go
Sina Mahmoodi f20eba426a
graphql, node, rpc: improve HTTP write timeout handling (#25457)
Here we add special handling for sending an error response when the write timeout of the
HTTP server is just about to expire. This is surprisingly difficult to get right, since is
must be ensured that all output is fully flushed in time, which needs support from
multiple levels of the RPC handler stack:

The timeout response can't use chunked transfer-encoding because there is no way to write
the final terminating chunk. net/http writes it when the topmost handler returns, but the
timeout will already be over by the time that happens. We decided to disable chunked
encoding by setting content-length explicitly.

Gzip compression must also be disabled for timeout responses because we don't know the
true content-length before compressing all output, i.e. compression would reintroduce
chunked transfer-encoding.
2022-12-07 14:02:14 +01:00

637 lines
17 KiB
Go

// Copyright 2020 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 <http://www.gnu.org/licenses/>.
package node
import (
"compress/gzip"
"context"
"fmt"
"io"
"net"
"net/http"
"sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rpc"
"github.com/rs/cors"
)
// httpConfig is the JSON-RPC/HTTP configuration.
type httpConfig struct {
Modules []string
CorsAllowedOrigins []string
Vhosts []string
prefix string // path prefix on which to mount http handler
jwtSecret []byte // optional JWT secret
}
// wsConfig is the JSON-RPC/Websocket configuration
type wsConfig struct {
Origins []string
Modules []string
prefix string // path prefix on which to mount ws handler
jwtSecret []byte // optional JWT secret
}
type rpcHandler struct {
http.Handler
server *rpc.Server
}
type httpServer struct {
log log.Logger
timeouts rpc.HTTPTimeouts
mux http.ServeMux // registered handlers go here
mu sync.Mutex
server *http.Server
listener net.Listener // non-nil when server is running
// HTTP RPC handler things.
httpConfig httpConfig
httpHandler atomic.Value // *rpcHandler
// WebSocket handler things.
wsConfig wsConfig
wsHandler atomic.Value // *rpcHandler
// These are set by setListenAddr.
endpoint string
host string
port int
handlerNames map[string]string
}
const (
shutdownTimeout = 5 * time.Second
)
func newHTTPServer(log log.Logger, timeouts rpc.HTTPTimeouts) *httpServer {
h := &httpServer{log: log, timeouts: timeouts, handlerNames: make(map[string]string)}
h.httpHandler.Store((*rpcHandler)(nil))
h.wsHandler.Store((*rpcHandler)(nil))
return h
}
// setListenAddr configures the listening address of the server.
// The address can only be set while the server isn't running.
func (h *httpServer) setListenAddr(host string, port int) error {
h.mu.Lock()
defer h.mu.Unlock()
if h.listener != nil && (host != h.host || port != h.port) {
return fmt.Errorf("HTTP server already running on %s", h.endpoint)
}
h.host, h.port = host, port
h.endpoint = fmt.Sprintf("%s:%d", host, port)
return nil
}
// listenAddr returns the listening address of the server.
func (h *httpServer) listenAddr() string {
h.mu.Lock()
defer h.mu.Unlock()
if h.listener != nil {
return h.listener.Addr().String()
}
return h.endpoint
}
// start starts the HTTP server if it is enabled and not already running.
func (h *httpServer) start() error {
h.mu.Lock()
defer h.mu.Unlock()
if h.endpoint == "" || h.listener != nil {
return nil // already running or not configured
}
// Initialize the server.
h.server = &http.Server{Handler: h}
if h.timeouts != (rpc.HTTPTimeouts{}) {
CheckTimeouts(&h.timeouts)
h.server.ReadTimeout = h.timeouts.ReadTimeout
h.server.ReadHeaderTimeout = h.timeouts.ReadHeaderTimeout
h.server.WriteTimeout = h.timeouts.WriteTimeout
h.server.IdleTimeout = h.timeouts.IdleTimeout
}
// Start the server.
listener, err := net.Listen("tcp", h.endpoint)
if err != nil {
// If the server fails to start, we need to clear out the RPC and WS
// configuration so they can be configured another time.
h.disableRPC()
h.disableWS()
return err
}
h.listener = listener
go h.server.Serve(listener)
if h.wsAllowed() {
url := fmt.Sprintf("ws://%v", listener.Addr())
if h.wsConfig.prefix != "" {
url += h.wsConfig.prefix
}
h.log.Info("WebSocket enabled", "url", url)
}
// if server is websocket only, return after logging
if !h.rpcAllowed() {
return nil
}
// Log http endpoint.
h.log.Info("HTTP server started",
"endpoint", listener.Addr(), "auth", (h.httpConfig.jwtSecret != nil),
"prefix", h.httpConfig.prefix,
"cors", strings.Join(h.httpConfig.CorsAllowedOrigins, ","),
"vhosts", strings.Join(h.httpConfig.Vhosts, ","),
)
// Log all handlers mounted on server.
var paths []string
for path := range h.handlerNames {
paths = append(paths, path)
}
sort.Strings(paths)
logged := make(map[string]bool, len(paths))
for _, path := range paths {
name := h.handlerNames[path]
if !logged[name] {
log.Info(name+" enabled", "url", "http://"+listener.Addr().String()+path)
logged[name] = true
}
}
return nil
}
func (h *httpServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// check if ws request and serve if ws enabled
ws := h.wsHandler.Load().(*rpcHandler)
if ws != nil && isWebsocket(r) {
if checkPath(r, h.wsConfig.prefix) {
ws.ServeHTTP(w, r)
}
return
}
// if http-rpc is enabled, try to serve request
rpc := h.httpHandler.Load().(*rpcHandler)
if rpc != nil {
// First try to route in the mux.
// Requests to a path below root are handled by the mux,
// which has all the handlers registered via Node.RegisterHandler.
// These are made available when RPC is enabled.
muxHandler, pattern := h.mux.Handler(r)
if pattern != "" {
muxHandler.ServeHTTP(w, r)
return
}
if checkPath(r, h.httpConfig.prefix) {
rpc.ServeHTTP(w, r)
return
}
}
w.WriteHeader(http.StatusNotFound)
}
// checkPath checks whether a given request URL matches a given path prefix.
func checkPath(r *http.Request, path string) bool {
// if no prefix has been specified, request URL must be on root
if path == "" {
return r.URL.Path == "/"
}
// otherwise, check to make sure prefix matches
return len(r.URL.Path) >= len(path) && r.URL.Path[:len(path)] == path
}
// validatePrefix checks if 'path' is a valid configuration value for the RPC prefix option.
func validatePrefix(what, path string) error {
if path == "" {
return nil
}
if path[0] != '/' {
return fmt.Errorf(`%s RPC path prefix %q does not contain leading "/"`, what, path)
}
if strings.ContainsAny(path, "?#") {
// This is just to avoid confusion. While these would match correctly (i.e. they'd
// match if URL-escaped into path), it's not easy to understand for users when
// setting that on the command line.
return fmt.Errorf("%s RPC path prefix %q contains URL meta-characters", what, path)
}
return nil
}
// stop shuts down the HTTP server.
func (h *httpServer) stop() {
h.mu.Lock()
defer h.mu.Unlock()
h.doStop()
}
func (h *httpServer) doStop() {
if h.listener == nil {
return // not running
}
// Shut down the server.
httpHandler := h.httpHandler.Load().(*rpcHandler)
wsHandler := h.wsHandler.Load().(*rpcHandler)
if httpHandler != nil {
h.httpHandler.Store((*rpcHandler)(nil))
httpHandler.server.Stop()
}
if wsHandler != nil {
h.wsHandler.Store((*rpcHandler)(nil))
wsHandler.server.Stop()
}
ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
defer cancel()
err := h.server.Shutdown(ctx)
if err != nil && err == ctx.Err() {
h.log.Warn("HTTP server graceful shutdown timed out")
h.server.Close()
}
h.listener.Close()
h.log.Info("HTTP server stopped", "endpoint", h.listener.Addr())
// Clear out everything to allow re-configuring it later.
h.host, h.port, h.endpoint = "", 0, ""
h.server, h.listener = nil, nil
}
// enableRPC turns on JSON-RPC over HTTP on the server.
func (h *httpServer) enableRPC(apis []rpc.API, config httpConfig) error {
h.mu.Lock()
defer h.mu.Unlock()
if h.rpcAllowed() {
return fmt.Errorf("JSON-RPC over HTTP is already enabled")
}
// Create RPC server and handler.
srv := rpc.NewServer()
if err := RegisterApis(apis, config.Modules, srv); err != nil {
return err
}
h.httpConfig = config
h.httpHandler.Store(&rpcHandler{
Handler: NewHTTPHandlerStack(srv, config.CorsAllowedOrigins, config.Vhosts, config.jwtSecret),
server: srv,
})
return nil
}
// disableRPC stops the HTTP RPC handler. This is internal, the caller must hold h.mu.
func (h *httpServer) disableRPC() bool {
handler := h.httpHandler.Load().(*rpcHandler)
if handler != nil {
h.httpHandler.Store((*rpcHandler)(nil))
handler.server.Stop()
}
return handler != nil
}
// enableWS turns on JSON-RPC over WebSocket on the server.
func (h *httpServer) enableWS(apis []rpc.API, config wsConfig) error {
h.mu.Lock()
defer h.mu.Unlock()
if h.wsAllowed() {
return fmt.Errorf("JSON-RPC over WebSocket is already enabled")
}
// Create RPC server and handler.
srv := rpc.NewServer()
if err := RegisterApis(apis, config.Modules, srv); err != nil {
return err
}
h.wsConfig = config
h.wsHandler.Store(&rpcHandler{
Handler: NewWSHandlerStack(srv.WebsocketHandler(config.Origins), config.jwtSecret),
server: srv,
})
return nil
}
// stopWS disables JSON-RPC over WebSocket and also stops the server if it only serves WebSocket.
func (h *httpServer) stopWS() {
h.mu.Lock()
defer h.mu.Unlock()
if h.disableWS() {
if !h.rpcAllowed() {
h.doStop()
}
}
}
// disableWS disables the WebSocket handler. This is internal, the caller must hold h.mu.
func (h *httpServer) disableWS() bool {
ws := h.wsHandler.Load().(*rpcHandler)
if ws != nil {
h.wsHandler.Store((*rpcHandler)(nil))
ws.server.Stop()
}
return ws != nil
}
// rpcAllowed returns true when JSON-RPC over HTTP is enabled.
func (h *httpServer) rpcAllowed() bool {
return h.httpHandler.Load().(*rpcHandler) != nil
}
// wsAllowed returns true when JSON-RPC over WebSocket is enabled.
func (h *httpServer) wsAllowed() bool {
return h.wsHandler.Load().(*rpcHandler) != nil
}
// isWebsocket checks the header of an http request for a websocket upgrade request.
func isWebsocket(r *http.Request) bool {
return strings.EqualFold(r.Header.Get("Upgrade"), "websocket") &&
strings.Contains(strings.ToLower(r.Header.Get("Connection")), "upgrade")
}
// NewHTTPHandlerStack returns wrapped http-related handlers
func NewHTTPHandlerStack(srv http.Handler, cors []string, vhosts []string, jwtSecret []byte) http.Handler {
// Wrap the CORS-handler within a host-handler
handler := newCorsHandler(srv, cors)
handler = newVHostHandler(vhosts, handler)
if len(jwtSecret) != 0 {
handler = newJWTHandler(jwtSecret, handler)
}
return newGzipHandler(handler)
}
// NewWSHandlerStack returns a wrapped ws-related handler.
func NewWSHandlerStack(srv http.Handler, jwtSecret []byte) http.Handler {
if len(jwtSecret) != 0 {
return newJWTHandler(jwtSecret, srv)
}
return srv
}
func newCorsHandler(srv http.Handler, allowedOrigins []string) http.Handler {
// disable CORS support if user has not specified a custom CORS configuration
if len(allowedOrigins) == 0 {
return srv
}
c := cors.New(cors.Options{
AllowedOrigins: allowedOrigins,
AllowedMethods: []string{http.MethodPost, http.MethodGet},
AllowedHeaders: []string{"*"},
MaxAge: 600,
})
return c.Handler(srv)
}
// virtualHostHandler is a handler which validates the Host-header of incoming requests.
// Using virtual hosts can help prevent DNS rebinding attacks, where a 'random' domain name points to
// the service ip address (but without CORS headers). By verifying the targeted virtual host, we can
// ensure that it's a destination that the node operator has defined.
type virtualHostHandler struct {
vhosts map[string]struct{}
next http.Handler
}
func newVHostHandler(vhosts []string, next http.Handler) http.Handler {
vhostMap := make(map[string]struct{})
for _, allowedHost := range vhosts {
vhostMap[strings.ToLower(allowedHost)] = struct{}{}
}
return &virtualHostHandler{vhostMap, next}
}
// ServeHTTP serves JSON-RPC requests over HTTP, implements http.Handler
func (h *virtualHostHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// if r.Host is not set, we can continue serving since a browser would set the Host header
if r.Host == "" {
h.next.ServeHTTP(w, r)
return
}
host, _, err := net.SplitHostPort(r.Host)
if err != nil {
// Either invalid (too many colons) or no port specified
host = r.Host
}
if ipAddr := net.ParseIP(host); ipAddr != nil {
// It's an IP address, we can serve that
h.next.ServeHTTP(w, r)
return
}
// Not an IP address, but a hostname. Need to validate
if _, exist := h.vhosts["*"]; exist {
h.next.ServeHTTP(w, r)
return
}
if _, exist := h.vhosts[host]; exist {
h.next.ServeHTTP(w, r)
return
}
http.Error(w, "invalid host specified", http.StatusForbidden)
}
var gzPool = sync.Pool{
New: func() interface{} {
w := gzip.NewWriter(io.Discard)
return w
},
}
type gzipResponseWriter struct {
resp http.ResponseWriter
gz *gzip.Writer
contentLength uint64 // total length of the uncompressed response
written uint64 // amount of written bytes from the uncompressed response
hasLength bool // true if uncompressed response had Content-Length
inited bool // true after init was called for the first time
}
// init runs just before response headers are written. Among other things, this function
// also decides whether compression will be applied at all.
func (w *gzipResponseWriter) init() {
if w.inited {
return
}
w.inited = true
hdr := w.resp.Header()
length := hdr.Get("content-length")
if len(length) > 0 {
if n, err := strconv.ParseUint(length, 10, 64); err != nil {
w.hasLength = true
w.contentLength = n
}
}
// Setting Transfer-Encoding to "identity" explicitly disables compression. net/http
// also recognizes this header value and uses it to disable "chunked" transfer
// encoding, trimming the header from the response. This means downstream handlers can
// set this without harm, even if they aren't wrapped by newGzipHandler.
//
// In go-ethereum, we use this signal to disable compression for certain error
// responses which are flushed out close to the write deadline of the response. For
// these cases, we want to avoid chunked transfer encoding and compression because
// they require additional output that may not get written in time.
passthrough := hdr.Get("transfer-encoding") == "identity"
if !passthrough {
w.gz = gzPool.Get().(*gzip.Writer)
w.gz.Reset(w.resp)
hdr.Del("content-length")
hdr.Set("content-encoding", "gzip")
}
}
func (w *gzipResponseWriter) Header() http.Header {
return w.resp.Header()
}
func (w *gzipResponseWriter) WriteHeader(status int) {
w.init()
w.resp.WriteHeader(status)
}
func (w *gzipResponseWriter) Write(b []byte) (int, error) {
w.init()
if w.gz == nil {
// Compression is disabled.
return w.resp.Write(b)
}
n, err := w.gz.Write(b)
w.written += uint64(n)
if w.hasLength && w.written >= w.contentLength {
// The HTTP handler has finished writing the entire uncompressed response. Close
// the gzip stream to ensure the footer will be seen by the client in case the
// response is flushed after this call to write.
err = w.gz.Close()
}
return n, err
}
func (w *gzipResponseWriter) Flush() {
if w.gz != nil {
w.gz.Flush()
}
if f, ok := w.resp.(http.Flusher); ok {
f.Flush()
}
}
func (w *gzipResponseWriter) close() {
if w.gz == nil {
return
}
w.gz.Close()
gzPool.Put(w.gz)
w.gz = nil
}
func newGzipHandler(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
next.ServeHTTP(w, r)
return
}
wrapper := &gzipResponseWriter{resp: w}
defer wrapper.close()
next.ServeHTTP(wrapper, r)
})
}
type ipcServer struct {
log log.Logger
endpoint string
mu sync.Mutex
listener net.Listener
srv *rpc.Server
}
func newIPCServer(log log.Logger, endpoint string) *ipcServer {
return &ipcServer{log: log, endpoint: endpoint}
}
// Start starts the httpServer's http.Server
func (is *ipcServer) start(apis []rpc.API) error {
is.mu.Lock()
defer is.mu.Unlock()
if is.listener != nil {
return nil // already running
}
listener, srv, err := rpc.StartIPCEndpoint(is.endpoint, apis)
if err != nil {
is.log.Warn("IPC opening failed", "url", is.endpoint, "error", err)
return err
}
is.log.Info("IPC endpoint opened", "url", is.endpoint)
is.listener, is.srv = listener, srv
return nil
}
func (is *ipcServer) stop() error {
is.mu.Lock()
defer is.mu.Unlock()
if is.listener == nil {
return nil // not running
}
err := is.listener.Close()
is.srv.Stop()
is.listener, is.srv = nil, nil
is.log.Info("IPC endpoint closed", "url", is.endpoint)
return err
}
// RegisterApis checks the given modules' availability, generates an allowlist based on the allowed modules,
// and then registers all of the APIs exposed by the services.
func RegisterApis(apis []rpc.API, modules []string, srv *rpc.Server) error {
if bad, available := checkModuleAvailability(modules, apis); len(bad) > 0 {
log.Error("Unavailable modules in HTTP API list", "unavailable", bad, "available", available)
}
// Generate the allow list based on the allowed modules
allowList := make(map[string]bool)
for _, module := range modules {
allowList[module] = true
}
// Register all the APIs exposed by the services
for _, api := range apis {
if allowList[api.Namespace] || len(allowList) == 0 {
if err := srv.RegisterName(api.Namespace, api.Service); err != nil {
return err
}
}
}
return nil
}