ceph-volume: main: initial take on main

Signed-off-by: Alfredo Deza <adeza@redhat.com>

src/ceph-volume/ceph_volume/main.py

@@ -0,0 +1,119 @@
+import os
+import pkg_resources
+import sys
+import logging
+
+from tambo import Transport
+import ceph_volume
+from ceph_volume.decorators import catches
+from ceph_volume import log
+
+
+class Volume(object):
+    _help = """
+ceph-volume: Deploy Ceph OSDs using different device technologies like lvm or
+physical disks
+
+Version: %s
+
+Global Options:
+--log, --logging    Set the level of logging. Acceptable values:
+                    debug, warning, error, critical
+--log-path          Change the default location ('/var/lib/ceph') for logging
+
+Log Path: %s
+
+Subcommands:
+lvm
+%s
+
+%s
+    """
+
+    def __init__(self, argv=None, parse=True):
+        self.mapper = {}
+        self.plugin_help = "No plugins found/loaded"
+        if argv is None:
+            argv = sys.argv
+        if parse:
+            self.main(argv)
+
+    def help(self):
+        return self._help % (
+            ceph_volume.__version__,
+            ceph_volume.config.get('log_path'),
+            self.plugin_help,
+            self.get_environ_vars()
+        )
+
+    def get_environ_vars(self):
+        environ_vars = []
+        for key, value in os.environ.items():
+            if key.startswith('CEPH_VOLUME'):
+                environ_vars.append("%s=%s" % (key, value))
+        if not environ_vars:
+            return ''
+        else:
+            environ_vars.insert(0, 'Environ Variables:')
+            return '\n'.join(environ_vars)
+
+    def enable_plugins(self):
+        """
+        Load all plugins available, add them to the mapper and extend the help
+        string with the information from each one
+        """
+        plugins = _load_library_extensions()
+        for plugin in plugins:
+            self.mapper[plugin._ceph_volume_name_] = plugin
+        self.plugin_help = '\n'.join(['%-19s %s\n' % (
+            plugin.name, getattr(plugin, 'help_menu', ''))
+            for plugin in plugins])
+
+    @catches((KeyboardInterrupt, RuntimeError))
+    def main(self, argv):
+        options = [['--log', '--logging']]
+        parser = Transport(argv, mapper=self.mapper,
+                           options=options, check_help=False,
+                           check_version=False)
+        parser.parse_args()
+        ceph_volume.config['verbosity'] = parser.get('--log', 'info')
+        log.setup(ceph_volume.config)
+        self.enable_plugins()
+        parser.catch_help = self.help()
+        parser.catch_version = ceph_volume.__version__
+        parser.mapper = self.mapper
+        if len(argv) <= 1:
+            return parser.print_help()
+        parser.dispatch()
+        parser.catches_help()
+        parser.catches_version()
+
+
+def _load_library_extensions():
+    """
+    Locate all setuptools entry points by the name 'ceph_volume_handlers'
+    and initialize them.
+    Any third-party library may register an entry point by adding the
+    following to their setup.py::
+
+        entry_points = {
+            'ceph_volume_handlers': [
+                'plugin_name = mylib.mymodule:Handler_Class',
+            ],
+        },
+
+    `plugin_name` will be used to load it as a sub command.
+    """
+    logger = logging.getLogger('ceph_volume.plugins')
+    group = 'ceph_volume_handlers'
+    entry_points = pkg_resources.iter_entry_points(group=group)
+    plugins = []
+    for ep in entry_points:
+        try:
+            logger.debug('loading %s' % ep.name)
+            plugin = ep.load()
+            plugin._ceph_volume_name_ = ep.name
+            plugins.append(plugin)
+        except Exception as error:
+            logger.exception("Error initializing plugin %s: %s" % (ep, error))
+    return plugins