Add get_k8s_logs Operator

Add a method to retrieve logs from Kubernetes Pod

Change-Id: I02e59c164881566d4c2b0d5decbe9eb0f3f30d34

charts/shipyard/templates/statefulset-airflow-worker.yaml

@@ -27,11 +27,12 @@ rules:
   - apiGroups:
       - ""
     resources:
+      - endpoints
       - nodes
       - nodes/proxy
-      - services
-      - endpoints
       - pods
+      - pods/log
+      - services
     verbs:
       - delete
       - get

shipyard_airflow/plugins/get_k8s_logs.py

@@ -0,0 +1,117 @@
+# Copyright 2018 AT&T Intellectual Property.  All other rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from kubernetes import client, config
+from kubernetes.client.rest import ApiException
+
+LOG = logging.getLogger(__name__)
+_NOT_FOUND_MSG_FMT = ("No matching pods found for namespace: {}"
+                      " pod: {} container: {}")
+
+
+class K8sLoggingException(Exception):
+    """ We do not really want the workflow to terminate due to logs
+        retrieval issues and hence we will have another Exception
+        handling class to handle this."""
+    pass
+
+
+def get_pod_logs(pod_name_pattern, namespace, container, since_seconds):
+    """This function retrieves the logs of the kubernetes pod
+
+       :param pod_name_pattern: Pattern of Pods name, e.g. 'drydock-api' if
+                                we want to check the logs of the Drydock API
+                                pods. Note that we are parsing pattern as
+                                there are usually multiple pods present (for
+                                redundancy purposes) and we will want to show
+                                the logs of all the relevant pods.
+       :param namespace: Namespace where Pods reside
+       :param container: The container for which to stream logs. Defaults
+                         to only container if there is one container in
+                         the pod.
+       :param since_seconds: A relative time in seconds before the current
+                             time from which to show logs. If this value
+                             precedes the time a pod was started, only logs
+                             since the pod start will be returned. If this
+                             value is in the future, no logs will be returned.
+
+        Example::
+
+            from get_k8s_logs import get_pod_logs
+
+            # Calls function to retrieve logs
+            get_pod_logs('airflow-worker', 'ucp', 'airflow-worker', 3600)
+    """
+    # Note that we are using 'in_cluster_config'
+    config.load_incluster_config()
+    v1 = client.CoreV1Api()
+
+    # Initialize variable
+    pods_list = []
+
+    # Retrieve names of pods
+    try:
+        ret = v1.list_namespaced_pod(namespace=namespace,
+                                     watch=False)
+
+    except ApiException as e:
+        LOG.error(e)
+        msg = ("Caught %s while trying to retrieve namespaced pods from K8s"
+               " API. Details: %s" % (e.__class__.__name__, e))
+        raise K8sLoggingException(msg)
+
+    if ret:
+        for i in ret.items:
+            if pod_name_pattern in i.metadata.name:
+                pods_list.append(i.metadata.name)
+    else:
+        raise K8sLoggingException(_NOT_FOUND_MSG_FMT.format(namespace,
+                                                            pod_name_pattern,
+                                                            container))
+
+    if pods_list:
+        LOG.info("The following Pods matched the requested pattern %s: %s",
+                 pod_name_pattern, ", ".join(pods_list))
+    else:
+        raise K8sLoggingException(_NOT_FOUND_MSG_FMT.format(namespace,
+                                                            pod_name_pattern,
+                                                            container))
+
+    # Retrieve logs from pod
+    for pod in pods_list:
+        try:
+            # Note that the kwarg 'pretty' takes on string value and will
+            # ensure that the output is pretty printed if set 'true'.
+            pod_logs = v1.read_namespaced_pod_log(name=pod,
+                                                  namespace=namespace,
+                                                  container=container,
+                                                  pretty='true',
+                                                  since_seconds=since_seconds)
+
+        except ApiException as e:
+            LOG.error(e)
+            msg = ("Caught %s while trying to read logs from namespaced pod=%s"
+                   ", namespace=%s, container=%s using the k8s API. Details: "
+                   "%s" % (e.__class__.__name__, pod, namespace, container, e))
+            raise K8sLoggingException(msg)
+
+        LOG.info("\n\n================= Logs for container %s of pods %s in"
+                 " namespace %s =================\n\n",
+                 container, pod, namespace)
+
+        LOG.info(pod_logs)
+
+        LOG.info("\n\n================= End Logs for %s =================\n\n",
+                 pod)