feat: add maxConnections and maxRequestBodySize limit setting.

config/config.go

@@ -48,9 +48,11 @@ type IPFSConfig struct {
 }
 
 type APIConfig struct {
-	ListenAddr   string `mapstructure:"listen-addr"`
-	WriteTimeout int64  `mapstructure:"write-timeout"`
-	ReadTimeout  int64  `mapstructure:"read-timeout"`
+	ListenAddr         string `mapstructure:"listen-addr"`
+	WriteTimeout       int64  `mapstructure:"write-timeout"`
+	ReadTimeout        int64  `mapstructure:"read-timeout"`
+	MaxConnections     int    `mapstructure:"max-connections"`
+	MaxRequestBodySize int64  `mapstructure:"max-request-body-size"`
 }
 
 func DefaultConfig() *Config {
@@ -81,9 +83,11 @@ func DefaultConfig() *Config {
 			IPFSNodeAddr: "127.0.0.1:5001",
 		},
 		API: APIConfig{
-			ListenAddr:   "127.0.0.1:8080",
-			WriteTimeout: 60,
-			ReadTimeout:  15,
+			ListenAddr:         "127.0.0.1:8080",
+			WriteTimeout:       60,
+			ReadTimeout:        15,
+			MaxConnections:     50,
+			MaxRequestBodySize: 4 << (10 * 2), // 4MB
 		},
 	}
 }

config/toml.go

@@ -70,6 +70,8 @@ ipfs-node-addr = "{{ .IPFS.IPFSNodeAddr }}"
 listen-addr = "{{ .API.ListenAddr }}"
 write-timeout = "{{ .API.WriteTimeout }}"
 read-timeout = "{{ .API.ReadTimeout }}"
+max-connections = "{{ .API.MaxConnections }}"
+max-request-body-size = "{{ .API.MaxRequestBodySize }}"
 `
 
 var configTemplate *template.Template

server/middleware/limit.go

@@ -0,0 +1,31 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+type limitMiddleware struct {
+	maxRequestBodySize int64
+}
+
+func NewLimitMiddleware(maxRequestBodySize int64) *limitMiddleware {
+	return &limitMiddleware{
+		maxRequestBodySize,
+	}
+}
+
+// Middleware limits the request body size.
+// This is done by first constraining to the ContentLength of the request headder,
+// and then reading the actual Body to constraint it.
+func (mw *limitMiddleware) Middleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.ContentLength > mw.maxRequestBodySize {
+			http.Error(w, "request body too large", http.StatusBadRequest)
+			return
+		}
+		r.Body = http.MaxBytesReader(w, r.Body, mw.maxRequestBodySize)
+		defer r.Body.Close()
+
+		next.ServeHTTP(w, r)
+	})
+}

server/middleware/limit_test.go

@@ -0,0 +1,102 @@
+package middleware_test
+
+import (
+	"bytes"
+	"crypto/rand"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/medibloc/panacea-oracle/server/middleware"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBodySizeSmallerThanLimitSetting(t *testing.T) {
+	testLimitMiddlewareHTTPRequest(
+		t,
+		newRequest(newRandomBody(1023)),
+		1024,
+		http.StatusOK,
+		"",
+	)
+}
+
+func TestBodySizeSameLimitSetting(t *testing.T) {
+	testLimitMiddlewareHTTPRequest(
+		t,
+		newRequest(newRandomBody(1024)),
+		1024,
+		http.StatusOK,
+		"",
+	)
+}
+
+func TestBodySizeLargeThanLimitSetting(t *testing.T) {
+	testLimitMiddlewareHTTPRequest(
+		t,
+		newRequest(newRandomBody(1025)),
+		1024,
+		http.StatusBadRequest,
+		"request body too large",
+	)
+}
+
+func TestDifferentBodySizeAndHeaderContentSize(t *testing.T) {
+	req := newRequest(newRandomBody(1025))
+	req.ContentLength = 1024
+
+	testLimitMiddlewareHTTPRequest(
+		t,
+		req,
+		1024,
+		http.StatusBadRequest,
+		"request body too large",
+	)
+}
+
+func newRandomBody(size int) []byte {
+	body := make([]byte, size)
+	if _, err := rand.Read(body); err != nil {
+		panic(err)
+	}
+
+	return body
+}
+
+func newRequest(body []byte) *http.Request {
+	return httptest.NewRequest(
+		"GET",
+		"http://test.com",
+		bytes.NewBuffer(body),
+	)
+}
+
+func testLimitMiddlewareHTTPRequest(
+	t *testing.T,
+	req *http.Request,
+	maxRequestBodySize int64,
+	statusCode int,
+	bodyMsg string,
+) {
+	w := httptest.NewRecorder()
+	mw := middleware.NewLimitMiddleware(maxRequestBodySize)
+	testHandler := mw.Middleware(
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			_, err := io.ReadAll(r.Body)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusBadRequest)
+			}
+		}),
+	)
+
+	testHandler.ServeHTTP(w, req)
+
+	resp := w.Result()
+	require.Equal(t, statusCode, resp.StatusCode)
+	if bodyMsg != "" {
+		body, err := io.ReadAll(resp.Body)
+		require.NoError(t, err)
+		require.Contains(t, string(body), bodyMsg)
+	}
+}

server/netutil_test.go

@@ -0,0 +1,90 @@
+package server_test
+
+import (
+	"io"
+	"net"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/netutil"
+)
+
+func TestNetUtil(t *testing.T) {
+
+	lis := &fakeListener{timeWait: 1}
+
+	limitLis := netutil.LimitListener(lis, 2)
+
+	wg := &sync.WaitGroup{}
+	start := time.Now()
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+
+			conn, err := limitLis.Accept()
+			require.NoError(t, err)
+			defer conn.Close()
+		}(i)
+	}
+
+	wg.Wait()
+	end := time.Now()
+
+	// Send 10 requests, process 2 at a time, and take 1 second per request.
+	// This request test should take 5 to 6 seconds.
+	require.True(t, start.Add(time.Second*5).Before(end))
+	require.True(t, start.Add(time.Second*6).After(end))
+
+}
+
+type fakeListener struct {
+	timeWait int64
+}
+
+// Accept waits for and returns the next connection to the listener.
+func (l *fakeListener) Accept() (net.Conn, error) {
+	time.Sleep(time.Second * time.Duration(l.timeWait))
+
+	return fakeNetConn{}, nil
+}
+
+// Close closes the listener.
+// Any blocked Accept operations will be unblocked and return errors.
+func (l *fakeListener) Close() error {
+	return nil
+}
+
+// Addr returns the listener's network address.
+func (l *fakeListener) Addr() net.Addr {
+	return fakeAddr(1)
+}
+
+type fakeNetConn struct {
+	io.Reader
+	io.Writer
+}
+
+func (c fakeNetConn) Close() error                       { return nil }
+func (c fakeNetConn) LocalAddr() net.Addr                { return localAddr }
+func (c fakeNetConn) RemoteAddr() net.Addr               { return remoteAddr }
+func (c fakeNetConn) SetDeadline(t time.Time) error      { return nil }
+func (c fakeNetConn) SetReadDeadline(t time.Time) error  { return nil }
+func (c fakeNetConn) SetWriteDeadline(t time.Time) error { return nil }
+
+type fakeAddr int
+
+var (
+	localAddr  = fakeAddr(1)
+	remoteAddr = fakeAddr(2)
+)
+
+func (a fakeAddr) Network() string {
+	return "net"
+}
+
+func (a fakeAddr) String() string {
+	return "str"
+}

server/server.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"net"
 	"net/http"
 	"time"
 
@@ -11,19 +12,24 @@ import (
 	"github.com/medibloc/panacea-oracle/server/service/status"
 	"github.com/medibloc/panacea-oracle/service"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/netutil"
 )
 
 type Server struct {
 	*http.Server
+	maxConnections int
 }
 
 func New(svc service.Service) *Server {
 	router := mux.NewRouter()
+	conf := svc.Config()
 
+	limitMiddleware := middleware.NewLimitMiddleware(conf.API.MaxRequestBodySize)
 	jwtAuthMiddleware := middleware.NewJWTAuthMiddleware(svc.QueryClient())
 
 	dealRouter := router.PathPrefix("/v0/data-deal").Subrouter()
 	dealRouter.Use(
+		limitMiddleware.Middleware,
 		jwtAuthMiddleware.Middleware,
 	)
 
@@ -35,14 +41,24 @@ func New(svc service.Service) *Server {
 	return &Server{
 		&http.Server{
 			Handler:      router,
-			Addr:         svc.Config().API.ListenAddr,
-			WriteTimeout: time.Duration(svc.Config().API.WriteTimeout) * time.Second,
-			ReadTimeout:  time.Duration(svc.Config().API.ReadTimeout) * time.Second,
+			Addr:         conf.API.ListenAddr,
+			WriteTimeout: time.Duration(conf.API.WriteTimeout) * time.Second,
+			ReadTimeout:  time.Duration(conf.API.ReadTimeout) * time.Second,
 		},
+		conf.API.MaxConnections,
 	}
 }
 
 func (srv *Server) Run() error {
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":http"
+	}
+	lis, err := net.Listen("tcp", addr)
+	if err != nil {
+		return err
+	}
+
 	log.Infof("HTTP server is started: %s", srv.Addr)
-	return srv.ListenAndServe()
+	return srv.Serve(netutil.LimitListener(lis, srv.maxConnections))
 }