Adds config-file arg option

Currently, the configurations are being loaded from a
statically defined file (/etc/monasca/agent/agent.yaml).

Adds CLI arg option for the configuration file (--config-file).
Also added this argument to the forwarder's tornado options, in
order to avoid exception due to unrecognised argument.

Co-Authored-By: Craig Bryant <craig.bryant@hpe.com>

Partially-Implements: blueprint add-windows-support

Change-Id: I400fdb3db6562a7171ecadcb27ee63ae4eaf8006

docs/Agent.md

@@ -236,6 +236,14 @@ A plugin config is specified something like this:
              env: stage
              newDim: test
 
+monasca-collector service can receive a `--config-file` argument, which represents an alternate agent configuration file, instead of the default /etc/monasca/agent.yaml.
+
+example:
+
+```
+monasca-collector --config-file="/path/to/monasca_agent.yaml"
+```
+
 # Running
 The monasca-setup command will create an appropriate startup script for the agent and so the agent can be run by using the standard daemon control tool for your operating system. If you have configured manually the startup script templates can be found in the code under the packaging directory.
 

monasca_agent/common/config.py

@@ -27,8 +27,15 @@ log = logging.getLogger(__name__)
 class Config(object):
 
     def __init__(self, configFile=None):
+        # importing it here, in order to avoid a circular import
+        # as monasca_agent.common.util imports this module.
+        from monasca_agent.common import util
+
+        options, args = util.get_parsed_args()
         if configFile is not None:
             self._configFile = configFile
+        elif options.config_file is not None:
+            self._configFile = options.config_file
         elif os.path.exists(DEFAULT_CONFIG_FILE):
             self._configFile = DEFAULT_CONFIG_FILE
         elif os.path.exists(os.getcwd() + '/agent.yaml'):

monasca_agent/common/util.py

@@ -444,6 +444,9 @@ def get_parsed_args():
     parser.add_option('-c', '--clean', action='store_true', default=False, dest='clean')
     parser.add_option('-v', '--verbose', action='store_true', default=False, dest='verbose',
                       help='Print out stacktraces for errors in checks')
+    parser.add_option('-f', '--config-file', default=None, dest='config_file',
+                      help='Location for an alternate config rather than '
+                           'using the default config location.')
 
     try:
         options, args = parser.parse_args()

monasca_agent/forwarder/daemon.py

@@ -207,6 +207,9 @@ def main():
     tornado.options.define("sslcheck", default=1, help="Verify SSL hostname, on by default")
     tornado.options.define("use_simple_http_client", default=0,
                            help="Use Tornado SimpleHTTPClient instead of CurlAsyncHTTPClient")
+    tornado.options.define("config_file", default=None,
+                           help="Location for an alternate config rather than "
+                                "using the default config location.")
     args = tornado.options.parse_command_line()
     skip_ssl_validation = False
     use_simple_http_client = False

monasca_agent/statsd/daemon.py

@@ -88,7 +88,7 @@ class MonascaStatsd(object):
 def main():
     """The main entry point for the unix version of monasca_statsd. """
     parser = argparse.ArgumentParser(description='Monasca statsd - statsd server supporting metric dimensions')
-    parser.add_argument('--config', '-c',
+    parser.add_argument('--config', '--config-file', '-c',
                         help="Location for an alternate config rather than using the default config location.")
     args = parser.parse_args()
 

tests/test_config.py

@@ -1,8 +1,10 @@
 # -*- coding: latin-1 -*-
 import unittest
+import mock
 import os.path
 import tempfile
 
+from monasca_agent.common import config
 from monasca_agent.common.config import Config
 from monasca_agent.common.util import PidFile, is_valid_hostname
 
@@ -84,6 +86,32 @@ class TestConfig(unittest.TestCase):
         self.assertTrue(conf_1 is conf_2)
         self.assertTrue(conf_1 is conf_3)
 
+    @mock.patch.object(Config, '_read_config')
+    @mock.patch('monasca_agent.common.util.get_parsed_args')
+    def testConfigFromParsedArgs(self, mock_parsed_args, mock_read_config):
+        mock_options = mock.Mock()
+        mock_parsed_args.return_value = (mock_options, mock.sentinel.args)
+        conf = Config()
+        # object is singleton, for this case, it needs to be reloaded.
+        conf.__init__()
+
+        self.assertEqual(mock_options.config_file, conf._configFile)
+
+    @mock.patch.object(Config, '_read_config')
+    @mock.patch('monasca_agent.common.util.get_parsed_args')
+    @mock.patch('monasca_agent.common.config.os')
+    def testConfigFileFromDefault(self, mock_os, mock_parsed_args, mock_read_config):
+        mock_os.path.exists = mock.create_autospec(mock_os.path.exists, return_value=True)
+        mock_options = mock.Mock()
+        mock_options.config_file = None
+        mock_parsed_args.return_value = (mock_options, mock.sentinel.args)
+        conf = Config()
+        # object is singleton, for this case, it needs to be reloaded.
+        conf.__init__()
+
+        self.assertEqual(config.DEFAULT_CONFIG_FILE, conf._configFile)
+        mock_os.path.exists.assert_called_once_with(config.DEFAULT_CONFIG_FILE)
+
 
 if __name__ == '__main__':
     unittest.main()