Changes made in wacth.py to print Empty newlines that are skipped when watching pod logs.

kubernetes/base/watch/watch.py

@@ -78,6 +78,8 @@ def iter_resp_lines(resp):
             buffer = buffer[next_newline+1:]
             if line:
                 yield line
+            else:
+                yield ''  # Only print one empty line
             next_newline = buffer.find(b'\n')
 
 
@@ -107,24 +109,29 @@ def get_watch_argument_name(self, func):
             return 'watch'
 
     def unmarshal_event(self, data, return_type):
-        js = json.loads(data)
-        js['raw_object'] = js['object']
-        # BOOKMARK event is treated the same as ERROR for a quick fix of
-        # decoding exception
-        # TODO: make use of the resource_version in BOOKMARK event for more
-        # efficient WATCH
-        if return_type and js['type'] != 'ERROR' and js['type'] != 'BOOKMARK':
-            obj = SimpleNamespace(data=json.dumps(js['raw_object']))
-            js['object'] = self._api_client.deserialize(obj, return_type)
-            if hasattr(js['object'], 'metadata'):
-                self.resource_version = js['object'].metadata.resource_version
-            # For custom objects that we don't have model defined, json
-            # deserialization results in dictionary
-            elif (isinstance(js['object'], dict) and 'metadata' in js['object']
-                  and 'resourceVersion' in js['object']['metadata']):
-                self.resource_version = js['object']['metadata'][
-                    'resourceVersion']
-        return js
+        if not data or data.isspace():
+            return None
+        try:
+            js = json.loads(data)
+            js['raw_object'] = js['object']
+            # BOOKMARK event is treated the same as ERROR for a quick fix of
+            # decoding exception
+            # TODO: make use of the resource_version in BOOKMARK event for more
+            # efficient WATCH
+            if return_type and js['type'] != 'ERROR' and js['type'] != 'BOOKMARK':
+                obj = SimpleNamespace(data=json.dumps(js['raw_object']))
+                js['object'] = self._api_client.deserialize(obj, return_type)
+                if hasattr(js['object'], 'metadata'):
+                    self.resource_version = js['object'].metadata.resource_version
+                # For custom objects that we don't have model defined, json
+                # deserialization results in dictionary
+                elif (isinstance(js['object'], dict) and 'metadata' in js['object']
+                      and 'resourceVersion' in js['object']['metadata']):
+                    self.resource_version = js['object']['metadata'][
+                        'resourceVersion']
+            return js
+        except json.JSONDecodeError:
+            return None
 
     def stream(self, func, *args, **kwargs):
         """Watch an API resource and stream the result back via a generator.
@@ -198,7 +205,10 @@ def stream(self, func, *args, **kwargs):
                             retry_after_410 = False
                             yield event
                     else:
-                        yield line
+                        if line:  
+                            yield line  # Normal non-empty line
+                        else:  
+                            yield ''  # Only yield one empty line  
                     if self._stop:
                         break
             finally:

kubernetes/base/watch/watch_test.py

@@ -14,12 +14,18 @@
 
 import unittest
 
+import os
+
+import time
+
 from unittest.mock import Mock, call
 
-from kubernetes import client
+from kubernetes import client,config
 
 from .watch import Watch
 
+from kubernetes.client import ApiException
+
 
 class WatchTests(unittest.TestCase):
     def setUp(self):
@@ -99,6 +105,9 @@ def test_watch_with_interspersed_newlines(self):
         # Note that "timeout_seconds" below is not a timeout; rather, it disables retries and is
         # the only way to do so. Without that, the stream will re-read the test data forever.
         for e in w.stream(fake_api.get_namespaces, timeout_seconds=1):
+            # Here added a statement for exception for empty lines.
+            if e is None:
+                continue
             count += 1
             self.assertEqual("test%d" % count, e['object'].metadata.name)
         self.assertEqual(3, count)
@@ -488,7 +497,84 @@ def test_watch_with_error_event_and_timeout_param(self):
             amt=None, decode_content=False)
         fake_resp.close.assert_called_once()
         fake_resp.release_conn.assert_called_once()
-
+
+    @classmethod
+    def setUpClass(cls):
+        cls.api = Mock()
+        cls.namespace = "default"
+
+    def test_pod_log_empty_lines(self):
+        pod_name = "demo-bug"
+
+        try:
+            self.api.create_namespaced_pod = Mock()
+            self.api.read_namespaced_pod = Mock()
+            self.api.delete_namespaced_pod = Mock()
+            self.api.read_namespaced_pod_log = Mock()
+
+            #pod creating step
+            self.api.create_namespaced_pod.return_value = None
+
+            #Checking pod status
+            mock_pod = Mock()
+            mock_pod.status.phase = "Running"
+            self.api.read_namespaced_pod.return_value = mock_pod
+
+            # Printing at pod output
+            self.api.read_namespaced_pod_log.return_value = iter(["Hello from Docker\n"])
+
+            # Wait for the pod to reach 'Running'
+            timeout = 60
+            start_time = time.time()
+            while time.time() - start_time < timeout:
+                pod = self.api.read_namespaced_pod(name=pod_name, namespace=self.namespace)
+                if pod.status.phase == "Running":
+                    break
+                time.sleep(2)
+            else:
+                self.fail("Pod did not reach 'Running' state within timeout")
+
+            # Reading and streaming logs using Watch (mocked)
+            w = Watch()
+            log_output = []
+            #Mock logs used for this test
+            w.stream = Mock(return_value=[
+                        "Hello from Docker",
+                        "",
+                        "",
+                        "\n\n",
+                        "Another log line",
+                        "",
+                        "\n",
+                        "Final log"
+                    ])
+            for event in w.stream(self.api.read_namespaced_pod_log, name=pod_name, namespace=self.namespace, follow=True):
+                log_output.append(event)
+                print(event)
+
+            # Print outputs
+            print(f"Captured logs: {log_output}") 
+            # self.assertTrue(any("Hello from Docker" in line for line in log_output))
+            # self.assertTrue(any(line.strip() == "" for line in log_output), "No empty lines found in logs")
+            expected_log = [
+                "Hello from Docker",
+                "",
+                "",
+                "\n\n",
+                "Another log line",
+                "",
+                "\n",
+                "Final log"
+            ]
+
+            self.assertEqual(log_output, expected_log, "Captured logs do not match expected logs")
+
+        except ApiException as e:
+            self.fail(f"Kubernetes API exception: {e}")
+        finally:
+            #checking pod is calling for delete
+            self.api.delete_namespaced_pod(name=pod_name, namespace=self.namespace)
+            self.api.delete_namespaced_pod.assert_called_once_with(name=pod_name, namespace=self.namespace)
 
 if __name__ == '__main__':
     unittest.main()