Bugfix: Invalid name when trimmed pod_id ends with hyphen in ``Kube…

…rnetesPodOperator`` (apache#15443)

When a pod name is more than `MAX_LABEL_LEN` (63 characters), it is trimmed to 63 chars

https://github.com/apache/airflow/blob/8711f90ab820ed420ef317b931e933a2062c891f/airflow/kubernetes/pod_generator.py#L470-L472

and we add a safe UUID to the `pod_id` joined by a dot `.`. However the regex
for Kubernetes name does not allow `-` followed by a `.`.

Valid Regex:

```
^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$
```

This commit strips any hypens at the end of the trimmed `pod_id`.

(cherry picked from commit 130f9e3)

airflow/kubernetes/pod_generator.py

@@ -468,7 +468,10 @@ def make_unique_pod_id(pod_id: str) -> str:
 
         safe_uuid = uuid.uuid4().hex  # safe uuid will always be less than 63 chars
         trimmed_pod_id = pod_id[:MAX_LABEL_LEN]
-        safe_pod_id = f"{trimmed_pod_id}.{safe_uuid}"
+
+        # Since we use '.' as separator we need to remove all the occurences of '-' if any
+        # in the trimmed_pod_id as the regex does not allow '-' followed by '.'.
+        safe_pod_id = f"{trimmed_pod_id.rstrip('-')}.{safe_uuid}"
 
         return safe_pod_id
 

tests/kubernetes/test_pod_generator.py

@@ -15,6 +15,7 @@
 # specific language governing permissions and limitations
 # under the License.
 import os
+import re
 import sys
 import unittest
 import uuid
@@ -656,6 +657,24 @@ def test_pod_name_confirm_to_max_length(self, _, pod_id):
             assert len(parts[0]) <= 63
         assert len(parts[1]) <= 63
 
+    @parameterized.expand(
+        (
+            ("pod-name-with-hyphen-", "pod-name-with-hyphen"),
+            ("pod-name-with-double-hyphen--", "pod-name-with-double-hyphen"),
+            ("pod0-name", "pod0-name"),
+            ("simple", "simple"),
+        )
+    )
+    def test_pod_name_is_valid(self, pod_id, expected_starts_with):
+        name = PodGenerator.make_unique_pod_id(pod_id)
+
+        regex = r"^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$"
+        assert (
+            len(name) <= 253 and all(ch.lower() == ch for ch in name) and re.match(regex, name)
+        ), "pod_id is invalid - fails allowed regex check"
+
+        assert name.rsplit(".")[0] == expected_starts_with
+
     def test_deserialize_model_string(self):
         fixture = """
 apiVersion: v1