14419: Fix concurrent map write.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tclegg@veritasgenetics.com>

diff --git a/sdk/go/keepclient/keepclient.go b/sdk/go/keepclient/keepclient.go
index 6a3e83796ed9fb7d9a91fdaff1bcab625d0ad909..ab610d65e71453ba8abc2287c5321a6a41dee217 100644 (file)
--- a/sdk/go/keepclient/keepclient.go
+++ b/sdk/go/keepclient/keepclient.go
@@ -546,31 +546,26 @@ func (kc *KeepClient) httpClient() HTTPClient {
                keepAlive = DefaultKeepAlive
        }
 
-       transport, ok := http.DefaultTransport.(*http.Transport)
-       if ok {
-               copy := *transport
-               transport = &copy
-       } else {
-               // Evidently the application has replaced
-               // http.DefaultTransport with a different type, so we
-               // need to build our own from scratch using the Go 1.8
-               // defaults.
-               transport = &http.Transport{
+       c := &http.Client{
+               Timeout: requestTimeout,
+               // It's not safe to copy *http.DefaultTransport
+               // because it has a mutex (which might be locked)
+               // protecting a private map (which might not be nil).
+               // So we build our own, using the Go 1.10 default
+               // values, ignoring any changes the application has
+               // made to http.DefaultTransport.
+               Transport: &http.Transport{
+                       DialContext: (&net.Dialer{
+                               Timeout:   connectTimeout,
+                               KeepAlive: keepAlive,
+                               DualStack: true,
+                       }).DialContext,
                        MaxIdleConns:          100,
                        IdleConnTimeout:       90 * time.Second,
+                       TLSHandshakeTimeout:   tlsTimeout,
                        ExpectContinueTimeout: time.Second,
-               }
-       }
-       transport.DialContext = (&net.Dialer{
-               Timeout:   connectTimeout,
-               KeepAlive: keepAlive,
-               DualStack: true,
-       }).DialContext
-       transport.TLSHandshakeTimeout = tlsTimeout
-       transport.TLSClientConfig = arvadosclient.MakeTLSConfig(kc.Arvados.ApiInsecure)
-       c := &http.Client{
-               Timeout:   requestTimeout,
-               Transport: transport,
+                       TLSClientConfig:       arvadosclient.MakeTLSConfig(kc.Arvados.ApiInsecure),
+               },
        }
        defaultClient[kc.Arvados.ApiInsecure][kc.foundNonDiskSvc] = c
        return c