fixed: always drain eventual request body.

It seems it is necessary to drain the request body in some situations when using http/2 otherwise it can cause stream errors.

See golang/go#26338

handlers.go

@@ -14,6 +14,8 @@ package bahamut
 import (
 	"context"
 	"fmt"
+	"io"
+	"io/ioutil"
 	"net/http"
 	"runtime/debug"
 
@@ -146,6 +148,20 @@ func handleEventualPanic(ctx context.Context, c chan error, disablePanicRecovery
 
 func runDispatcher(ctx *bcontext, r *elemental.Response, d func() error, disablePanicRecovery bool, marshallers map[elemental.Identity]CustomMarshaller) *elemental.Response {
 
+	defer func() {
+
+		// It seems it is necessary to drain the request body
+		// in some situations when using http/2 otherwise it can cause stream errors.
+		// See https://github.com/golang/go/issues/26338 and associated issues.
+
+		if ctx.Request() == nil || ctx.Request().HTTPRequest() == nil {
+			return
+		}
+
+		_, _ = io.Copy(ioutil.Discard, ctx.Request().HTTPRequest().Body)
+		_ = ctx.Request().HTTPRequest().Body.Close() // nolint
+	}()
+
 	e := make(chan error)
 
 	go func() {

handlers_test.go

@@ -12,6 +12,7 @@
 package bahamut
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"net/http"
@@ -468,13 +469,21 @@ func TestHandlers_runDispatcher(t *testing.T) {
 
 		calledCounter := &counter{}
 
+		hreq, err := http.NewRequest(http.MethodGet, "https://127.0.0.1/list", bytes.NewBuffer([]byte("hello")))
+		if err != nil {
+			panic(err)
+		}
 		gctx, cancel := context.WithTimeout(context.Background(), 300*time.Millisecond)
 		defer cancel()
 
 		ctx := newContext(context.Background(), elemental.NewRequest())
-		ctx.request = elemental.NewRequest()
 		ctx.ctx = gctx
 
+		ctx.request, err = elemental.NewRequestFromHTTPRequest(hreq, testmodel.Manager())
+		if err != nil {
+			panic(err)
+		}
+
 		response := elemental.NewResponse(elemental.NewRequest())
 
 		d := func() error {