Add plugin registry

conda-store-server/conda_store_server/plugins/plugin_context.py

@@ -15,7 +15,7 @@ class PluginContext:
         * the variables: conda_store, log, stdout, stderr
         * the functions: run_command, run
     """
-    def __init__(self, conda_store=None, stdout=None, stderr=None):
+    def __init__(self, conda_store=None, stdout=None, stderr=None, log_level=logging.INFO):
         if stdout is not None and stderr is None:
             stderr = stdout
 
@@ -25,8 +25,7 @@ def __init__(self, conda_store=None, stdout=None, stderr=None):
         self.log = logging.getLogger(f"conda_store_server.plugins.plugin_context.{self.id}")
         self.log.propagate = False
         self.log.addHandler(logging.StreamHandler(stream=self.stdout))
-        # TODO: get log level from config
-        self.log.setLevel(logging.INFO)
+        self.log.setLevel(log_level)
         self.conda_store = conda_store
 
     def run_command(self, command, redirect_stderr=True, **kwargs):

conda-store-server/conda_store_server/plugins/registry.py

@@ -0,0 +1,36 @@
+# Copyright (c) conda-store development team. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+from conda_store_server.plugins import BUILTIN_PLUGINS
+
+
+class PluginRegistry():
+    _instance = None
+
+    def __new__(cls):
+        if cls._instance is None:
+            cls._instance = super(PluginRegistry, cls).__new__(cls)
+        return cls._instance
+
+    def __init__(self):
+        # plugins are registered in the map of the form:
+        # {plugin_name: plugin_class}
+        self.registered = {}
+
+    def list_plugin_names(self):
+        return self.registered.keys()
+
+    def get_plugin(self, name):
+        return self.registered.get(name)
+
+    def register_plugin(self, p):
+        """Adds plugin to the list of registered plugins"""
+        plugin_name = p.name()
+        if plugin_name not in self.registered:
+            self.registered[plugin_name] = p
+
+    def collect_plugins(self):
+        """Registers all availble plugins with the plugin registry"""
+        for plugin in BUILTIN_PLUGINS:
+            self.register_plugin(plugin)