Convert zuul_return into action plugin

Today we expect zuul_return to be run on localhost (zuul-executor).
With that in mind, convert to an action plugin so it only runs on a
zuul-executor.

Change-Id: I236360563c812ee628f78ac062e9ae6cc183aee4
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

zuul/ansible/library/zuul_return.py

@@ -1,88 +0,0 @@
-#!/usr/bin/python
-
-# Copyright (c) 2017 Red Hat
-#
-# This module is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This software is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this software.  If not, see <http://www.gnu.org/licenses/>.
-
-import os
-import json
-import tempfile
-
-
-def merge_dict(dict_a, dict_b):
-    """
-    Add dict_a into dict_b
-    Merge values if possible else dict_a value replace dict_b value
-    """
-    for key in dict_a:
-        if key in dict_b:
-            if isinstance(dict_a[key], dict) and isinstance(dict_b[key], dict):
-                merge_dict(dict_a[key], dict_b[key])
-            else:
-                dict_b[key] = dict_a[key]
-        else:
-            dict_b[key] = dict_a[key]
-    return dict_b
-
-
-def set_value(path, new_data, new_file):
-    workdir = os.path.dirname(path)
-    data = None
-    if os.path.exists(path):
-        with open(path, 'r') as f:
-            data = f.read()
-    if data:
-        data = json.loads(data)
-    else:
-        data = {}
-
-    if new_file:
-        with open(new_file, 'r') as f:
-            merge_dict(json.load(f), data)
-    if new_data:
-        merge_dict(new_data, data)
-
-    (f, tmp_path) = tempfile.mkstemp(dir=workdir)
-    try:
-        f = os.fdopen(f, 'w')
-        json.dump(data, f)
-        f.close()
-        os.rename(tmp_path, path)
-    except Exception:
-        os.unlink(tmp_path)
-        raise
-
-
-def main():
-    module = AnsibleModule(
-        argument_spec=dict(
-            path=dict(required=False, type='str'),
-            data=dict(required=False, type='dict'),
-            file=dict(required=False, type='str'),
-        )
-    )
-
-    p = module.params
-    path = p['path']
-    if not path:
-        path = os.path.join(os.environ['ZUUL_JOBDIR'], 'work',
-                            'results.json')
-    set_value(path, p['data'], p['file'])
-    module.exit_json(changed=True, e=os.environ.copy())
-
-from ansible.module_utils.basic import *  # noqa
-from ansible.module_utils.basic import AnsibleModule
-
-if __name__ == '__main__':
-    main()