client-go: add unit test for Request thread safety

Kubernetes-commit: ca492a9b62a586caf3e3cd22bc020108a63fb395

rest/request_test.go

@@ -31,6 +31,7 @@ import (
  "reflect"
  "strings"
  "sync"
+ "sync/atomic"
  "syscall"
  "testing"
  "time"
@@ -3987,3 +3988,50 @@ func TestRetryableConditions(t *testing.T) {
  }
  }
 }
+
+func TestRequestConcurrencyWithRetry(t *testing.T) {
+ var attempts int32
+ client := clientForFunc(func(req *http.Request) (*http.Response, error) {
+ defer func() {
+ atomic.AddInt32(&attempts, 1)
+ }()
+
+ // always send a retry-after response
+ return &http.Response{
+ StatusCode: http.StatusInternalServerError,
+ Header: http.Header{"Retry-After": []string{"1"}},
+ }, nil
+ })
+
+ req := &Request{
+ verb: "POST",
+ c: &RESTClient{
+ content: defaultContentConfig(),
+ Client: client,
+ },
+ backoff: &noSleepBackOff{},
+ maxRetries: 9, // 10 attempts in total, including the first
+ retryFn: defaultRequestRetryFn,
+ }
+
+ concurrency := 20
+ wg := sync.WaitGroup{}
+ wg.Add(concurrency)
+ startCh := make(chan struct{})
+ for i := 0; i < concurrency; i++ {
+ go func() {
+ defer wg.Done()
+ <-startCh
+ req.Do(context.Background())
+ }()
+ }
+
+ close(startCh)
+ wg.Wait()
+
+ // we expect (concurrency*req.maxRetries+1) attempts to be recorded
+ expected := concurrency * (req.maxRetries + 1)
+ if atomic.LoadInt32(&attempts) != int32(expected) {
+ t.Errorf("Expected attempts: %d, but got: %d", expected, attempts)
+ }
+}