Replace retrying with tenacity

We are replacing all usages of the 'retrying' package with
'tenacity' as the author of retrying is not actively maintaining
the project. Tenacity is a fork of retrying, but has improved the
interface and extensibility (see [1] for more details). Our end
goal here is removing the retrying package from our requirements.

Tenacity provides the same functionality as retrying, but has the
following major differences to account for:
- tenacity uses seconds rather than ms as retrying did.
- tenacity has different kwargs for the decorator and
Retrying class itself.
- tenacity has a different approach for retrying args by
using classes for its stop/wait/retry kwargs.
- By default tenacity raises a RetryError if a retried callable
times out; retrying raises the last exception from the callable.
Tenacity provides backwards compatibility here by offering
the 'reraise' kwarg.
- tenacity defines 'time.sleep' as a default value for a kwarg.
That said consumers who need to mock patch time.sleep
need to account for this via mocking of time.sleep before
tenacity is imported.

This patch updates all usages of retrying with tenacity.
Unit tests will be added where applicable.

Note: This change is not newton critical so projects are welcome
to hold off on committing until post-newton. Ideally this change
will merge by the first part of Ocata so dependant functionality
can land and have time to solidify for Ocata.

[1] https://github.com/jd/tenacity

Change-Id: I18a0075e9a7c376b6881555ce67267a8944caafa

murano/cfapi/cfapi.py

@@ -17,8 +17,8 @@ import uuid
 
 from oslo_config import cfg
 from oslo_log import log as logging
-import retrying
 import six
+import tenacity
 from webob import response
 
 from murano.common.i18n import _LI, _LW
@@ -224,11 +224,11 @@ class Controller(object):
             for action_id in list(actions):
                 if 'getCredentials' in action_id:
 
-                    @retrying.retry(retry_on_exception=lambda e: isinstance(e,
-                                    TypeError),
-                                    wait_random_min=1000,
-                                    wait_random_max=10000,
-                                    stop_max_delay=30000)
+                    @tenacity.retry(
+                        retry=tenacity.retry_if_exception_type(TypeError),
+                        wait=tenacity.wait_random(min=1, max=10),
+                        stop=tenacity.stop_after_delay(30),
+                        reraise=True)
                     def _get_creds(client, task_id, environment_id):
                         result = m_cli.actions.get_result(environment_id,
                                                           task_id)['result']

murano/engine/system/net_explorer.py

@@ -20,7 +20,7 @@ import neutronclient.v2_0.client as nclient
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import uuidutils
-import retrying
+import tenacity
 
 from murano.common import auth_utils
 from murano.common import exceptions as exc
@@ -60,10 +60,11 @@ class NetworkExplorer(object):
     # NOTE(starodubcevna): to avoid simultaneous router requests we use retry
     # decorator with random delay 1-10 seconds between attempts and maximum
     # delay time 30 seconds.
-    @retrying.retry(retry_on_exception=lambda e: isinstance(e,
-                    exc.RouterInfoException),
-                    wait_random_min=1000, wait_random_max=10000,
-                    stop_max_delay=30000)
+    @tenacity.retry(
+        retry=tenacity.retry_if_exception_type(exc.RouterInfoException),
+        stop=tenacity.stop_after_delay(30),
+        wait=tenacity.wait_random(min=1, max=10),
+        reraise=True)
     def get_default_router(self):
         router_name = self._settings.router_name
 

requirements.txt

@@ -10,7 +10,7 @@ eventlet!=0.18.3,>=0.18.2 # MIT
 PasteDeploy>=1.5.0 # MIT
 Routes!=2.0,!=2.1,!=2.3.0,>=1.12.3;python_version=='2.7' # MIT
 Routes!=2.0,!=2.3.0,>=1.12.3;python_version!='2.7' # MIT
-retrying!=1.3.0,>=1.2.3 # Apache-2.0
+tenacity>=3.1.0  # Apache-2.0
 WebOb>=1.2.3 # MIT
 kombu>=3.0.25 # BSD
 psutil<2.0.0,>=1.1.1 # BSD