move Type into its own file

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>

lib/cdist/core/type.py

@@ -0,0 +1,125 @@
+# -*- coding: utf-8 -*-
+#
+# 2010-2011 Steven Armstrong (steven-cdist at armstrong.cc)
+#
+# This file is part of cdist.
+#
+# cdist 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.
+#
+# cdist 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 cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+import os
+
+import cdist
+
+
+class Type(object):
+
+    @staticmethod
+    def base_dir():
+        """Return the absolute path to the top level directory where types
+        are defined.
+
+        Requires the environment variable '__cdist_base_dir' to be set.
+
+        """
+        try:
+            return os.path.join(
+                os.environ['__cdist_base_dir'],
+                'conf',
+                'type'
+            )
+        except KeyError as e:
+            raise cdist.MissingEnvironmentVariableError(e.args[0])
+
+    @classmethod
+    def list_types(cls):
+        """Return a list of type instances"""
+        for type_name in cls.list_type_names():
+            yield cls(type_name)
+
+    @classmethod
+    def list_type_names(cls):
+        """Return a list of type names"""
+        return os.listdir(cls.base_dir())
+
+
+    def __init__(self, name):
+        self.name = name
+        self.__explorers = None
+        self.__required_parameters = None
+        self.__optional_parameters = None
+
+    def __repr__(self):
+        return '<Type name=%s>' % self.name
+
+    @property
+    def path(self):
+        return os.path.join(
+            self.base_dir(),
+            self.name
+        ) 
+
+    @property
+    def is_singleton(self):
+        """Check whether a type is a singleton."""
+        return os.path.isfile(os.path.join(self.path, "singleton"))
+
+    @property
+    def is_install(self):
+        """Check whether a type is used for installation (if not: for configuration)"""
+        return os.path.isfile(os.path.join(self.path, "install"))
+
+    @property
+    def explorers(self):
+        """Return a list of available explorers"""
+        if not self.__explorers:
+            try:
+                self.__explorers = os.listdir(os.path.join(self.path, "explorer"))
+            except EnvironmentError as e:
+                # error ignored
+                self.__explorers = []
+        return self.__explorers
+
+    @property
+    def required_parameters(self):
+        """Return a list of required parameters"""
+        if not self.__required_parameters:
+            parameters = []
+            try:
+                with open(os.path.join(self.path, "parameter", "required")) as fd:
+                    for line in fd:
+                        parameters.append(line.strip())
+            except EnvironmentError as e:
+                # error ignored
+                pass
+            finally:
+                self.__required_parameters = parameters
+        return self.__required_parameters
+
+    @property
+    def optional_parameters(self):
+        """Return a list of optional parameters"""
+        if not self.__optional_parameters:
+            parameters = []
+            try:
+                with open(os.path.join(self.path, "parameter", "optional")) as fd:
+                    for line in fd:
+                        parameters.append(line.strip())
+            except EnvironmentError as e:
+                # error ignored
+                pass
+            finally:
+                self.__optional_parameters = parameters
+        return self.__optional_parameters