virtcontainers: clh: Do not use the default HTTP client

When enabling tracing with Cloud Hypervisor, we end up establishing 2
connections to 2 different HTTP servers: The Cloud Hypervisor API one
that runs over a UNIX socket and the Jaeger endpoint running over UDP.

Both connections use the default HTTP golang client instance, and thus
share the same transport layer. As the Cloud Hypervisor implementation
sets it up to be over a Unix socket, the jaeger uploader ends up going
through that transport as well, and sending its spans to the Cloud
Hypervisor API server.

We fix that by giving the Cloud Hypervisor implementation its own HTTP
client instance and we avoid sharing it with anything else in the shim.

Fixes #2364

Signed-off-by: Samuel Ortiz <samuel.e.ortiz@protonmail.com>

src/runtime/virtcontainers/clh.go

@@ -281,6 +281,22 @@ func (clh *cloudHypervisor) createSandbox(ctx context.Context, id string, networ
 	}
 	clh.state.apiSocket = apiSocketPath
 
+	cfg := chclient.NewConfiguration()
+	cfg.HTTPClient = &http.Client{
+		Transport: &http.Transport{
+			DialContext: func(ctx context.Context, network, path string) (net.Conn, error) {
+				addr, err := net.ResolveUnixAddr("unix", clh.state.apiSocket)
+				if err != nil {
+					return nil, err
+				}
+
+				return net.DialUnix("unix", nil, addr)
+			},
+		},
+	}
+
+	clh.APIClient = chclient.NewAPIClient(cfg).DefaultApi
+
 	clh.virtiofsd = &virtiofsd{
 		path:       clh.config.VirtioFSDaemon,
 		sourcePath: filepath.Join(getSharePath(clh.id)),
@@ -968,34 +984,9 @@ func (clh *cloudHypervisor) isClhRunning(timeout uint) (bool, error) {
 }
 
 func (clh *cloudHypervisor) client() clhClient {
-	if clh.APIClient == nil {
-		clh.APIClient = clh.newAPIClient()
-	}
-
 	return clh.APIClient
 }
 
-func (clh *cloudHypervisor) newAPIClient() *chclient.DefaultApiService {
-
-	cfg := chclient.NewConfiguration()
-
-	socketTransport := &http.Transport{
-		DialContext: func(ctx context.Context, network, path string) (net.Conn, error) {
-			addr, err := net.ResolveUnixAddr("unix", clh.state.apiSocket)
-			if err != nil {
-				return nil, err
-			}
-
-			return net.DialUnix("unix", nil, addr)
-		},
-	}
-
-	cfg.HTTPClient = http.DefaultClient
-	cfg.HTTPClient.Transport = socketTransport
-
-	return chclient.NewAPIClient(cfg).DefaultApi
-}
-
 func openAPIClientError(err error) error {
 
 	if err == nil {