Add first iteration of http client

The offline client is ideal for running offline and locally.
The http client uses requests to do actual http requests to an API
server.

Change-Id: I2b1ed6068ab547d55237b3f9ff7150935232caa6

ara/clients/http.py

@@ -0,0 +1,127 @@
+#  Copyright (c) 2018 Red Hat, Inc.
+#
+#  This file is part of ARA: Ansible Run Analysis.
+#
+#  ARA 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.
+#
+#  ARA 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 ARA.  If not, see <http://www.gnu.org/licenses/>.
+
+# This is an "offline" API client that does not require standing up
+# an API server and does not execute actual HTTP calls.
+
+import json
+import logging
+import requests
+
+
+class HttpClient(object):
+    def __init__(self, endpoint='http://127.0.0.1:8000', timeout=30, **params):
+        self.endpoint = endpoint
+        self.timeout = timeout
+        self.params = params
+
+        self.log = logging.getLogger(__name__)
+        self.user_agent = 'ara-http-client'
+        self.log.debug("%s: %s" % (self.user_agent, str(self.params)))
+
+        self.http = requests.Session()
+
+    def _request(self, method, url, **kwargs):
+        # Override timeout and headers only if user supplied
+        kwargs.setdefault('timeout', self.timeout)
+        kwargs.setdefault('headers', kwargs.get('headers', {}))
+
+        # Headers we're enforcing (kind of)
+        kwargs['headers']['User-Agent'] = self.user_agent
+        kwargs['headers']['Accept'] = 'application/json'
+        kwargs['headers']['Content-Type'] = 'application/json'
+
+        self.log.debug("%s on %s" % (method, url))
+
+        # Use requests.Session to do the query
+        # The actual endpoint is:
+        # <endpoint>              <url>
+        # http://127.0.0.1:8000 / api/v1/playbooks
+        return self.http.request(method, self.endpoint + url, **kwargs)
+
+    def get(self, url, **kwargs):
+        return self._request('get', url, **kwargs)
+
+    def patch(self, url, **kwargs):
+        return self._request('patch', url, **kwargs)
+
+    def post(self, url, **kwargs):
+        return self._request('post', url, **kwargs)
+
+    def put(self, url, **kwargs):
+        return self._request('put', url, **kwargs)
+
+    def delete(self, url, **kwargs):
+        return self._request('delete', url, **kwargs)
+
+
+class AraHttpClient(object):
+    def __init__(self):
+        self.log = logging.getLogger(__name__)
+        self.client = HttpClient()
+
+    def _request(self, method, url, **kwargs):
+        func = getattr(self.client, method)
+        # TODO: Is there a better way than doing this if/else ?
+        if kwargs:
+            response = func(url, json.dumps(kwargs))
+        else:
+            response = func(url)
+
+        if response.status_code >= 500:
+            self.log.error(
+                'Failed to {method} on {url}: {content}'.format(
+                    method=method,
+                    url=url,
+                    content=kwargs
+                )
+            )
+
+        self.log.debug('HTTP {status}: {method} on {url}'.format(
+            status=response.status_code,
+            method=method,
+            url=url
+        ))
+
+        if response.status_code not in [200, 201, 204]:
+            self.log.error(
+                'Failed to {method} on {url}: {content}'.format(
+                    method=method,
+                    url=url,
+                    content=kwargs
+                )
+            )
+
+        if response.status_code == 204:
+            return response
+
+        return response.json()
+
+    def get(self, endpoint, **kwargs):
+        return self._request('get', endpoint, **kwargs)
+
+    def patch(self, endpoint, **kwargs):
+        return self._request('patch', endpoint, **kwargs)
+
+    def post(self, endpoint, **kwargs):
+        return self._request('post', endpoint, **kwargs)
+
+    def put(self, endpoint, **kwargs):
+        return self._request('put', endpoint, **kwargs)
+
+    def delete(self, endpoint, **kwargs):
+        return self._request('delete', endpoint, **kwargs)

ara/clients/offline.py

@@ -22,16 +22,21 @@ import json
 import logging
 import os
 
+try:
     from django import setup as django_setup
     from django.core.management import execute_from_command_line
     from django.test import Client
 
     os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'ara.server.settings')
+
     # Automatically create the database and run migrations (is there a better way?)
     execute_from_command_line(['django', 'migrate'])
 
     # Set up the things Django needs
     django_setup()
+except ImportError as e:
+    print('ERROR: The offline client requires ara-server to be installed')
+    raise e
 
 
 class AraOfflineClient(object):

ara/clients/utils.py

@@ -16,10 +16,13 @@
 #  along with ARA.  If not, see <http://www.gnu.org/licenses/>.
 
 from ara.clients.offline import AraOfflineClient
+from ara.clients.http import AraHttpClient
 
 
 def get_client(client=None, **kwargs):
     if client is None or client == 'offline':
         return AraOfflineClient(**kwargs)
+    elif client == 'http':
+        return AraHttpClient(**kwargs)
     else:
         raise ValueError('Unsupported client: %s' % client)