[computes] add k8s label selector filter for service discovery

In some cases, there might be multiple clusters running in the same
k8s environment. In such cases, we can pass a label selector to limit
the k8s namespaces that hue service-discovery looks at.

Change-Id: Ib98aeeafc7a19313abc3d7bc81bc17e4b646dd43

desktop/core/src/desktop/management/commands/sync_warehouses.py

@@ -17,16 +17,18 @@
 
 # HUE_CONF_DIR=/etc/hue/conf HUE_IGNORE_PASSWORD_SCRIPT_ERRORS=1 /opt/hive/build/env/bin/hue sync_warehouses
 
-from beeswax import models
-from beeswax.conf import AUTH_USERNAME, AUTH_PASSWORD
-from django.core.management.base import BaseCommand
-from hadoop import confparse
-import json
-from kubernetes import client, config
-import logging
 import os
 import re
 import sys
+import json
+import logging
+
+from django.core.management.base import BaseCommand
+from kubernetes import client, config
+
+from beeswax import models
+from beeswax.conf import AUTH_PASSWORD, AUTH_USERNAME
+from hadoop import confparse
 
 LOG = logging.getLogger()
 
@@ -95,15 +97,17 @@ def get_computes_from_k8s():
   catalogs = []
   computes = []
 
-  for n in core_v1.list_namespace().items:
+  label_selector = os.environ.get("K8S_LABEL_SELECTOR")  # clusterid=env-urmgt6-env
+
+  for n in core_v1.list_namespace(label_selector=label_selector).items:
     try:
       namespace = n.metadata.name
       LOG.info('Getting details for ns: %s' % namespace)
       item = {
         'name': n.metadata.labels.get('displayname'),
         'description': '%s (%s)' % (n.metadata.labels.get('displayname'), n.metadata.name),
         'external_id': namespace,
-        #'creation_timestamp': n.metadata.labels.get('creation_timestamp'),
+        # 'creation_timestamp': n.metadata.labels.get('creation_timestamp'),
       }
 
       if namespace.startswith('warehouse-'):
@@ -119,6 +123,7 @@ def get_computes_from_k8s():
 
   return computes
 
+
 def update_hive_configs(namespace, hive, host, port=80):
   hs2_stfs = apps_v1.read_namespaced_stateful_set('hiveserver2', namespace)
 
@@ -187,6 +192,7 @@ def populate_impala(namespace, impala):
       impala['api_port'] = next((p.port for p in ports if p.name == 'web'), 25000)
       update_impala_configs(namespace, impala, 'coordinator.%s.svc.cluster.local' % namespace)
 
+
 def update_impala_configs(namespace, impala, host):
   hive_configs = core_v1.read_namespaced_config_map('impala-coordinator-hive-conf', namespace)
   hive_site_data = confparse.ConfParse(hive_configs.data['hive-site.xml'])