Manage ansible installations within zuul

As a first step towards supporting multiple ansible versions we need
tooling to manage ansible installations. This moves the installation
of ansible from the requirements.txt into zuul. This is called as a
setup hook to install the ansible versions into
<prefix>/lib/zuul/ansible. Further this tooling abstracts knowledge
that the executor must know in order to actually run the correct
version of ansible.

The actual usage of multiple ansible versions will be done in
follow-ups.

For better maintainability the ansible plugins live in
zuul/ansible/base where plugins can be kept in different versions if
necessary. For each supported ansible version there is a specific
folder that symlinks the according plugins.

Change-Id: I5ce1385245c76818777aa34230786a9dbaf723e5
Depends-On: https://review.openstack.org/623927

zuul/cmd/manage_ansible.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+# Copyright 2019 BMW Group
+#
+# 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
+import zuul.cmd
+from zuul.lib.ansible import AnsibleManager
+
+
+class ManageAnsible(zuul.cmd.ZuulApp):
+
+    app_name = 'manage-ansible'
+    app_description = 'Zuul ansible maager'
+    log = logging.getLogger('zuul.ManageAnsible')
+
+    def createParser(self):
+        parser = super().createParser()
+        parser.add_argument('-v', dest='verbose', action='store_true',
+                            help='verbose output')
+        parser.add_argument('-u', dest='upgrade', action='store_true',
+                            help='upgrade ansible versions')
+        return parser
+
+    def _setup_logging(self):
+        """Manage ansible logging does not rely on conf file"""
+        if self.args.verbose:
+            logging.basicConfig(level=logging.DEBUG)
+        else:
+            logging.basicConfig(level=logging.INFO)
+
+    def main(self):
+        self.parseArguments()
+        try:
+            self.readConfig()
+        except Exception:
+            # This script must be able to run without config so this can be
+            # safely ignored here.
+            pass
+        self._setup_logging()
+
+        manager = AnsibleManager()
+
+        manager.install(upgrade=self.args.upgrade)
+
+
+def main():
+    ManageAnsible().main()
+
+
+if __name__ == "__main__":
+    main()