Default to beta API for eks get-token

* Stop logging a warning on an empty KUBERNETES_EXEC_INFO

Signed-off-by: Micah Hausler <mhausler@amazon.com>

awscli/customizations/eks/get_token.py

@@ -126,8 +126,8 @@ def _run_main(self, parsed_args, parsed_globals):
     def discover_api_version(self):
         """
         Parses the KUBERNETES_EXEC_INFO environment variable and returns the
-        API version. If the environment variable is empty, malformed, or
-        invalid, return the v1alpha1 response and print a message to stderr.
+        API version. If the environment variable is malformed or invalid,
+        return the v1beta1 response and print a message to stderr.
 
         If the v1alpha1 API is specified explicitly, a message is printed to
         stderr with instructions to update.
@@ -139,7 +139,7 @@ def discover_api_version(self):
         # "v1beta1" will be removed. At or around that time, EKS will likely
         # support v1.22 through v1.28, in which client API version "v1beta1"
         # will be supported by all EKS versions.
-        fallback_api_version = ALPHA_API
+        fallback_api_version = BETA_API
 
         error_prefixes = {
             "error": "Error parsing",
@@ -148,16 +148,12 @@ def discover_api_version(self):
 
         exec_info_raw = os.environ.get("KUBERNETES_EXEC_INFO", "")
         if not exec_info_raw:
-            # All kube clients should be setting this. Otherewise, we'll return
-            # the fallback and write an error.
-            uni_print(
-                ERROR_MSG_TPL.format(
-                    error_prefixes["empty"],
-                    fallback_api_version,
-                ),
-                sys.stderr,
-            )
-            uni_print("\n", sys.stderr)
+            # All kube clients should be setting this, but client-go clients
+            # (kubectl, kubelet, etc) < 1.20 were not setting this if the API
+            # version defined in the kubeconfig was not v1alpha1.
+            #
+            # This was changed in kubernetes/kubernetes#95489 so that
+            # KUBERNETES_EXEC_INFO is always provided
             return fallback_api_version
         try:
             exec_info = json.loads(exec_info_raw)

tests/functional/eks/test_get_token.py

@@ -203,16 +203,10 @@ def test_api_version_discovery_empty(self):
 
         self.assertEqual(
             response["apiVersion"],
-            "client.authentication.k8s.io/v1alpha1",
+            "client.authentication.k8s.io/v1beta1",
         )
 
-        self.assertEqual(
-            stderr,
-            (
-                "Empty KUBERNETES_EXEC_INFO, defaulting to client.authentication.k8s.io/v1alpha1. "
-                "This is likely a bug in your Kubernetes client. Please update your Kubernetes client.\n"
-            ),
-        )
+        self.assertEqual(stderr, "",)
 
     def test_api_version_discovery_v1(self):
         self.set_kubernetes_exec_info('v1')