Configure ElasticSearch URL prefix using environment variable

.gitignore

@@ -15,3 +15,4 @@ build/
 
 my_rules
 *.swp
+*~

docs/source/elastalert.rst

@@ -125,7 +125,7 @@ The environment variable ``ES_USE_SSL`` will override this field.
 
 ``es_password``: Optional; basic-auth password for connecting to ``es_host``. The environment variable ``ES_PASSWORD`` will override this field.
 
-``es_url_prefix``: Optional; URL prefix for the Elasticsearch endpoint.
+``es_url_prefix``: Optional; URL prefix for the Elasticsearch endpoint.  The environment variable ``ES_URL_PREFIX`` will override this field.
 
 ``es_send_get_body_as``: Optional; Method for querying Elasticsearch - ``GET``, ``POST`` or ``source``. The default is ``GET``
 

elastalert/config.py

@@ -37,7 +37,8 @@
                 'ES_PASSWORD': 'es_password',
                 'ES_USERNAME': 'es_username',
                 'ES_HOST': 'es_host',
-                'ES_PORT': 'es_port'}
+                'ES_PORT': 'es_port',
+                'ES_URL_PREFIX': 'es_url_prefix'}
 
 env = Env(ES_USE_SSL=bool)
 

tests/config_test.py

@@ -233,6 +233,22 @@ def test_load_ssl_env_true():
                 assert rules['use_ssl'] is True
 
 
+def test_load_url_prefix_env():
+    test_rule_copy = copy.deepcopy(test_rule)
+    test_rule_copy.pop('es_host')
+    test_rule_copy.pop('es_port')
+    test_config_copy = copy.deepcopy(test_config)
+    with mock.patch('elastalert.config.yaml_loader') as mock_open:
+        mock_open.side_effect = [test_config_copy, test_rule_copy]
+
+        with mock.patch('os.listdir') as mock_ls:
+            with mock.patch.dict(os.environ, {'ES_URL_PREFIX': 'es/'}):
+                mock_ls.return_value = ['testrule.yaml']
+                rules = load_rules(test_args)
+
+                assert rules['es_url_prefix'] == 'es/'
+
+
 def test_load_disabled_rules():
     test_rule_copy = copy.deepcopy(test_rule)
     test_rule_copy['is_enabled'] = False