fix: newlines for messages in k8s log tail

Author: clumsy

torchx/schedulers/kubernetes_scheduler.py

@@ -1073,7 +1073,10 @@ def log_iter(
         core_api = client.CoreV1Api(self._api_client())
         if should_tail:
             w = watch.Watch()
-            iterator = w.stream(core_api.read_namespaced_pod_log, **args)
+            iterator = (
+                f"{line}\n"
+                for line in w.stream(core_api.read_namespaced_pod_log, **args)
+            )
         else:
             resp = core_api.read_namespaced_pod_log(**args)
             iterator = split_lines(resp)

torchx/schedulers/test/kubernetes_scheduler_test.py

@@ -1144,6 +1144,25 @@ def test_log_iter(self, read_namespaced_pod_log: MagicMock) -> None:
             },
         )
 
+    @patch("kubernetes.watch.Watch.stream")
+    def test_log_iter_tail(self, watch_stream: MagicMock) -> None:
+        scheduler = create_scheduler("test")
+        watch_stream.return_value = iter(["line1", "line2", "line3"])
+        lines = scheduler.log_iter(
+            app_id="testnamespace:testjob",
+            role_name="role_blah",
+            k=1,
+            should_tail=True,
+        )
+        self.assertEqual(
+            list(lines),
+            [
+                "line1\n",
+                "line2\n",
+                "line3\n",
+            ],
+        )
+
     def test_push_patches(self) -> None:
         # Configure mock to return proper response for schedule() call
         self.mock_create.return_value = {"metadata": {"name": "testjob"}}