Open
Description
~/go/src$ go version
go version devel +24ea77559f Thu Apr 9 11:09:00 2020 -0400 linux/amd64
~/go/src$ go doc httptest.Server.Close
package httptest // import "net/http/httptest"
func (s *Server) Close()
Close shuts down the server and blocks until all outstanding requests on
this server have completed.
While investigating #37669, I saw a reported race that led me to believe that, contrary to its documentation, (*httptest.Server).Close was not blocking for requests to complete.
To check that hypothesis, I added the following test function:
diff --git c/src/net/http/httptest/server_test.go w/src/net/http/httptest/server_test.go
index 0aad15c5ed..8b0e0f137f 100644
--- c/src/net/http/httptest/server_test.go
+++ w/src/net/http/httptest/server_test.go
@@ -6,9 +6,12 @@ package httptest
import (
"bufio"
+ "context"
+ "io"
"io/ioutil"
"net"
"net/http"
+ "strings"
"testing"
)
@@ -238,3 +241,51 @@ func TestTLSServerWithHTTP2(t *testing.T) {
})
}
}
+
+func TestCloseBlocksUntilRequestsCompleted(t *testing.T) {
+ t.Parallel()
+
+ modes := []string{
+ "http1",
+ "http2",
+ }
+
+ for _, mode := range modes {
+ mode := mode
+ t.Run(mode, func(t *testing.T) {
+ t.Parallel()
+
+ ctx, cancel := context.WithCancel(context.Background())
+ closed := false
+
+ cst := NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ cancel()
+
+ io.Copy(w, r.Body)
+
+ <-r.Context().Done()
+ if closed {
+ panic("Close did not wait for handler to return")
+ }
+ }))
+
+ switch mode {
+ case "http1":
+ cst.Start()
+ case "http2":
+ cst.EnableHTTP2 = true
+ cst.StartTLS()
+ }
+ defer func() {
+ cst.Close()
+ closed = true
+ }()
+
+ req, _ := http.NewRequestWithContext(ctx, "POST", cst.URL, strings.NewReader("Hello, server!"))
+ resp, err := cst.Client().Do(req)
+ if err == nil {
+ resp.Body.Close()
+ }
+ })
+ }
+}It reliably fails under the race detector with even a very modest count, indicating that the server is not waiting for the handler to complete when HTTP/2 is enabled:
~/go/src$ go test -race net/http/httptest -run=TestCloseBlocksUntilRequestsCompleted -count=10
==================
WARNING: DATA RACE
Write at 0x00c000202018 by goroutine 10:
net/http/httptest.TestCloseBlocksUntilRequestsCompleted.func1.2()
/usr/local/google/home/bcmills/go/src/net/http/httptest/server_test.go:281 +0x46
net/http/httptest.TestCloseBlocksUntilRequestsCompleted.func1()
/usr/local/google/home/bcmills/go/src/net/http/httptest/server_test.go:289 +0x508
testing.tRunner()
/usr/local/google/home/bcmills/go/src/testing/testing.go:1022 +0x1eb
Previous read at 0x00c000202018 by goroutine 31:
net/http/httptest.TestCloseBlocksUntilRequestsCompleted.func1.1()
/usr/local/google/home/bcmills/go/src/net/http/httptest/server_test.go:267 +0x18b
net/http.HandlerFunc.ServeHTTP()
/usr/local/google/home/bcmills/go/src/net/http/server.go:2012 +0x51
net/http.serverHandler.ServeHTTP()
/usr/local/google/home/bcmills/go/src/net/http/server.go:2808 +0xc4
net/http.initALPNRequest.ServeHTTP()
/usr/local/google/home/bcmills/go/src/net/http/server.go:3380 +0xfc
net/http.(*initALPNRequest).ServeHTTP()
<autogenerated>:1 +0xa6
net/http.Handler.ServeHTTP-fm()
/usr/local/google/home/bcmills/go/src/net/http/server.go:87 +0x64
net/http.(*http2serverConn).runHandler()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:5712 +0xc0
Goroutine 10 (running) created at:
testing.(*T).Run()
/usr/local/google/home/bcmills/go/src/testing/testing.go:1073 +0x6a3
net/http/httptest.TestCloseBlocksUntilRequestsCompleted()
/usr/local/google/home/bcmills/go/src/net/http/httptest/server_test.go:255 +0x13e
testing.tRunner()
/usr/local/google/home/bcmills/go/src/testing/testing.go:1022 +0x1eb
Goroutine 31 (finished) created at:
net/http.(*http2serverConn).processHeaders()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:5446 +0x8fb
net/http.(*http2serverConn).processFrame()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:4975 +0x44a
net/http.(*http2serverConn).processFrameFromReader()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:4933 +0x750
net/http.(*http2serverConn).serve()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:4432 +0x1485
net/http.(*http2Server).ServeConn()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:4033 +0xd88
net/http.http2ConfigureServer.func1()
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:3859 +0x117
net/http.(*conn).serve()
/usr/local/google/home/bcmills/go/src/net/http/server.go:1805 +0x1c77
==================
--- FAIL: TestCloseBlocksUntilRequestsCompleted (0.00s)
--- FAIL: TestCloseBlocksUntilRequestsCompleted/http2 (0.02s)
testing.go:937: race detected during execution of test
2020/04/10 16:35:14 http2: panic serving 127.0.0.1:46044: Close did not wait for handler to return
goroutine 132 [running]:
net/http.(*http2serverConn).runHandler.func1(0xc0000ae068, 0xc00022af4f, 0xc00031a180)
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:5705 +0x231
panic(0x8b5220, 0x9c14f0)
/usr/local/google/home/bcmills/go/src/runtime/panic.go:975 +0x3b3
net/http/httptest.TestCloseBlocksUntilRequestsCompleted.func1.1(0x9cd0c0, 0xc0000ae068, 0xc0000ac600)
/usr/local/google/home/bcmills/go/src/net/http/httptest/server_test.go:268 +0x1e2
net/http.HandlerFunc.ServeHTTP(0xc000096740, 0x9cd0c0, 0xc0000ae068, 0xc0000ac600)
/usr/local/google/home/bcmills/go/src/net/http/server.go:2012 +0x52
net/http.serverHandler.ServeHTTP(0xc0000a8460, 0x9cd0c0, 0xc0000ae068, 0xc0000ac600)
/usr/local/google/home/bcmills/go/src/net/http/server.go:2808 +0xc5
net/http.initALPNRequest.ServeHTTP(0x9cd940, 0xc000282b70, 0xc00029a380, 0xc0000a8460, 0x9cd0c0, 0xc0000ae068, 0xc0000ac600)
/usr/local/google/home/bcmills/go/src/net/http/server.go:3380 +0xfd
net/http.(*http2serverConn).runHandler(0xc00031a180, 0xc0000ae068, 0xc0000ac600, 0xc0000977c0)
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:5712 +0xc1
created by net/http.(*http2serverConn).processHeaders
/usr/local/google/home/bcmills/go/src/net/http/h2_bundle.go:5446 +0x8fc
FAIL
FAIL net/http/httptest 0.202s
FAIL