Also handle client.authentication.k8s.io/v1alpha1.

Author: jglick

util/src/main/java/io/kubernetes/client/util/KubeConfig.java

@@ -257,8 +257,8 @@ private String tokenViaExecCredential(Map<String, Object> execMap) {
       return null;
     }
     String apiVersion = (String) execMap.get("apiVersion");
-    if (!"client.authentication.k8s.io/v1beta1".equals(apiVersion)) {
-      // TODO or v1alpha1 is apparently identical and could be supported
+    if (!"client.authentication.k8s.io/v1beta1".equals(apiVersion)
+        && !"client.authentication.k8s.io/v1alpha1".equals(apiVersion)) {
       log.error("Unrecognized user.exec.apiVersion: {}", apiVersion);
       return null;
     }

util/src/test/java/io/kubernetes/client/util/KubeConfigTest.java

@@ -298,6 +298,13 @@ public void testExecCredentials() throws Exception {
     assertEquals("abc123", kc.getAccessToken());
   }
 
+  @Test
+  public void testExecCredentialsAlpha1() throws Exception {
+    KubeConfig kc =
+        KubeConfig.loadKubeConfig(new StringReader(KUBECONFIG_EXEC.replace("v1beta1", "v1alpha1")));
+    assertEquals("abc123", kc.getAccessToken());
+  }
+
   private static final String KUBECONFIG_EXEC_ENV =
       "apiVersion: v1\n"
           + "current-context: c\n"