Configuration from a ini formated file

docs/source/config.rst

@@ -4,18 +4,20 @@ Configuration (pkgmeta.cfg)
 In order to setup a repository, one needs to configure using a basic INI file.
 
 The configuration fairly simple. There is one INI section that is special,
-it is called ``pkgmeta``. This section is used to configure ``pkgmeta``
-itself. Any other sections in the file are repository definitions.
+it is called ``pkgmeta``. This section is used to configure globals.
+Any other sections in the file are repository definitions.
 
-Configuration example
+Example configuration
 ---------------------
 
+The following configuration selects the ``myrepo`` as the default repository. The ``myrepo`` repository using the filesystem storage type and sources from ``pkgmeta.org``.
 ::
 
     [pkgmeta]
     default = myrepo
 
     [myrepo]
+    type = fs
     sources =
         http://repo.pkgmeta.org/ pypi
 	http://repo.pkgmeta.org/ private

pkgmeta/config.py

@@ -1,13 +1,30 @@
 # -*- coding: utf-8 -*-
+from configparser import ConfigParser
+from pkgmeta.exceptions import PkgMetaConfigFileError
 from pkgmeta.storage import lookup_storage_by_type
 __all__ = ('PkgMetaConfig',
            'RepositoryConfig', 'FileSystemRepositoryConfig',
            )
 
 
+class RepositoryConfig:
+    """A repository configuration"""
+
+    def __init__(self, name, type=None, sources=None,
+                 **kwargs):
+        self.name = name
+        self.type = type
+        self.sources = sources
+        if self.sources is None:
+            self.sources = []
+        for name, value in kwargs.items():
+            setattr(self, name, value)
+        storage_factory = lookup_storage_by_type(self.type)
+        self.storage = storage_factory(self)
+
+
 class PkgMetaConfig(object):
-    """Configuration
-    """
+    """Main pkgmeta configuration object"""
 
     def __init__(self, repositories, default=None):
         if not hasattr(repositories, '__iter__'):
@@ -16,9 +33,39 @@ def __init__(self, repositories, default=None):
         for repo in self.repositories:
             if not isinstance(repo, RepositoryConfig):
                 raise TypeError("%s is not a RepsitoryConfig" % repr(repo))
-        if default is None:
+        self.default = default
+        if self.default is None:
             self.default = repositories[0].name
 
+    @classmethod
+    def from_file(cls, file):
+        cfg = ConfigParser(allow_no_value=True)
+        cfg.read(file)
+        if cfg.has_section('pkgmeta') and cfg.has_option('pkgmeta', 'default'):
+            default = cfg.get('pkgmeta', 'default')
+        else:
+            default = None
+        repositories = []
+        for section in cfg.sections():
+            if section == 'pkgmeta':
+                continue
+            # TODO Wrap config init errors with a PkgMetaConfigFileError
+            config = RepositoryConfig(section, **dict(cfg.items(section)))
+            repositories.append(config)
+        if len(repositories) == 0:
+            raise PkgMetaConfigFileError("Missing a repository definition")
+        # Find the default repositories index
+        if default is not None:
+            repo_keys = [r.name for r in repositories]
+            try:
+                repo_keys.index(default)
+            except ValueError as err:
+                raise PkgMetaConfigFileError("Invalid default repository")
+        inst = cls(repositories, default=default)
+        setattr(inst, '__from__', 'from_file')
+        setattr(inst, '_file', file)
+        return inst
+
     def __iter__(self):
         return iter(self.repositories)
 
@@ -32,19 +79,3 @@ def get_repository_config(self, name=None):
         except IndexError:
             raise LookupError("Could not find '%s'" % name)
         return repo_config
-
-
-class RepositoryConfig:
-    """A repository configuration"""
-
-    def __init__(self, name, type=None, sources=None,
-                 **kwargs):
-        self.name = name
-        self.type = type
-        self.sources = sources
-        if self.sources is None:
-            self.sources = []
-        for name, value in kwargs.items():
-            setattr(self, name, value)
-        storage_factory = lookup_storage_by_type(self.type)
-        self.storage = storage_factory(self)

pkgmeta/exceptions.py

@@ -4,6 +4,7 @@
     'InvalidVersion',
     'RepositoryIsNotMutable', 'RepositoryNotFound',
     'ReleaseNotFound',
+    'PkgMetaConfigFileError',
     )
 
 
@@ -25,3 +26,8 @@ class ReleaseNotFound(KeyError):
 
 class UnknownRepositoryStorageType(Exception):
     """Raised when an unknown storage type is requested."""
+
+
+class PkgMetaConfigFileError(Exception):
+    """Raised when there is an issue with reading/writing a pkgmeta.cfg file.
+    """

pkgmeta/tests/test_config.py

@@ -4,6 +4,19 @@
 import tempfile
 from pkgmeta.tests import unittest
 
+TEST_PKGMETA_CFG = """\
+[pkgmeta]
+default = repo2
+
+[repo1]
+
+[repo2]
+
+[repo3]
+type = filesystem
+location = %(location)s
+"""
+
 
 class PkgMetaConfigTestCase(unittest.TestCase):
 
@@ -89,3 +102,50 @@ def test_arbitrary_attributes(self):
         config = self.make_one('repo', foo='foo', bar='foobar')
         self.assertEqual(config.foo, 'foo')
         self.assertEqual(config.bar, 'foobar')
+
+
+class ConfigurationFromAFileTest(unittest.TestCase):
+    """Read in the configuration from a pkgmeta.cfg file."""
+
+    def write_config(self, content):
+        dummy, file = tempfile.mkstemp()
+        with open(file, 'w') as f:
+            f.write(content)
+        return file
+
+    def make_one(self, file):
+        from pkgmeta.config import PkgMetaConfig
+        return PkgMetaConfig.from_file(file)
+
+    def test_blank_file(self):
+        from pkgmeta.exceptions import PkgMetaConfigFileError
+        file = self.write_config('\n')
+        with self.assertRaises(PkgMetaConfigFileError) as error:
+            self.make_one(file)
+        self.assertEqual(str(error.exception),
+                         "Missing a repository definition")
+
+    def test_invalid_default_value(self):
+        from pkgmeta.exceptions import PkgMetaConfigFileError
+        content = """\
+[pkgmeta]
+default = nothere
+
+[repo]
+"""
+        file = self.write_config(content)
+        with self.assertRaises(PkgMetaConfigFileError) as error:
+            self.make_one(file)
+        self.assertEqual(str(error.exception),
+                         "Invalid default repository")
+
+    def test_correct_init_values(self):
+        location = tempfile.mkdtemp()
+        file = self.write_config(TEST_PKGMETA_CFG % dict(location=location))
+        config = self.make_one(file)
+        default_repo = config.get_repository_config()
+        self.assertEqual(default_repo.name, 'repo2')
+        # Check to see if the configuration variables made it through
+        from pkgmeta.storage import FileSystemStorage
+        repo3 = config.get_repository_config('repo3')
+        self.assertTrue(isinstance(repo3.storage, FileSystemStorage))