documented Packages base class

1 files changed, 189 insertions, 36 deletions

diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py b/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
index 06b1b78c0..083bcd5e8 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
@@ -9,7 +9,10 @@ from Bcfg2.Compat import ConfigParser, urlopen
 from Bcfg2.Server.Plugins.Packages import Collection
 from Bcfg2.Server.Plugins.Packages.PackagesSources import PackagesSources
 
+#: The default path for generated yum configs
 YUM_CONFIG_DEFAULT = "/etc/yum.repos.d/bcfg2.repo"
+
+#: The default path for generated apt configs
 APT_CONFIG_DEFAULT = "/etc/apt/sources.d/bcfg2"
 
 
@@ -18,8 +21,22 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                Bcfg2.Server.Plugin.Generator,
                Bcfg2.Server.Plugin.Connector,
                Bcfg2.Server.Plugin.ClientRunHooks):
-    name = 'Packages'
+    """ Packages resolves Package entries on the Bcfg2 server in order
+    to present a complete list of Package entries to the client in
+    order to determine the completeness of the client configuration.
+    It does so by delegating control of package version information to
+    a number of backends, which may parse repository metadata directly
+    or defer to package manager libraries for truly dynamic
+    resolution.
+
+    .. private-include: _build_packages, _get_collection"""
+
+    #: Packages is an alternative to
+    #: :mod:`Bcfg2.Server.Plugins.Pkgmgr` and conflicts with it.
     conflicts = ['Pkgmgr']
+
+    #: Packages exposes two additional XML-RPC calls, :func:`Refresh`
+    #: and :func:`Reload`
     __rmi__ = Bcfg2.Server.Plugin.Plugin.__rmi__ + ['Refresh', 'Reload']
 
     def __init__(self, core, datastore):
@@ -43,14 +60,21 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
         self.sources = PackagesSources(os.path.join(self.data, "sources.xml"),
                                        self.cachepath, core.fam, self,
                                        self.core.setup)
+    __init__.__doc__ = Bcfg2.Server.Plugin.Plugin.__init__.__doc__
 
     def toggle_debug(self):
         rv = Bcfg2.Server.Plugin.Plugin.toggle_debug(self)
         self.sources.toggle_debug()
         return rv
+    toggle_debug.__doc__ = Bcfg2.Server.Plugin.Plugin.toggle_debug.__doc__
 
     @property
     def disableResolver(self):
+        """ Report the state of the resolver.  This can be disabled in
+        the configuration.  Note that disabling metadata (see
+        :attr:`disableMetaData`) implies disabling the resolver.
+
+        This property cannot be set. """
         if self.disableMetaData:
             # disabling metadata without disabling the resolver Breaks
             # Things
@@ -64,11 +88,16 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
             # "disabled", which are not handled according to the
             # Python docs but appear to be handled properly by
             # ConfigParser in at least some versions
-            return self.core.setup.cfp.get("packages", "resolver",
-                                           default="enabled").lower() == "disabled"
+            return self.core.setup.cfp.get(
+                "packages",
+                "resolver",
+                default="enabled").lower() == "disabled"
 
     @property
     def disableMetaData(self):
+        """ Report whether or not metadata processing is enabled.
+
+        This property cannot be set. """
         try:
             return not self.core.setup.cfp.getboolean("packages", "resolver")
         except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
@@ -76,11 +105,20 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
         except ValueError:
             # for historical reasons we also accept "enabled" and
             # "disabled"
-            return self.core.setup.cfp.get("packages", "metadata",
-                                           default="enabled").lower() == "disabled"
+            return self.core.setup.cfp.get(
+                "packages",
+                "metadata",
+                default="enabled").lower() == "disabled"
 
     def create_config(self, entry, metadata):
-        """ create yum/apt config for the specified host """
+        """ Create yum/apt config for the specified client.
+
+        :param entry: The base entry to bind.  This will be modified
+                      in place.
+        :type entry: lxml.etree._Element
+        :param metadata: The client to create the config for.
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        """
         attrib = dict(encoding='ascii',
                       owner='root',
                       group='root',
@@ -94,6 +132,21 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
             entry.attrib.__setitem__(key, value)
 
     def HandleEntry(self, entry, metadata):
+        """ Bind configuration entries.  ``HandleEntry`` handles
+        entries two different ways:
+
+        * All ``Package`` entries have their ``version`` and ``type``
+          attributes set according to the appropriate
+          :class:`Bcfg2.Server.Plugins.Packages.Collection._Collection`
+          object for this client.
+        * ``Path`` entries are delegated to :func:`create_config`
+
+        :param entry: The entry to bind
+        :type entry: lxml.etree._Element
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :return: lxml.etree._Element - The fully bound entry
+        """
         if entry.tag == 'Package':
             collection = self._get_collection(metadata)
             entry.set('version', self.core.setup.cfp.get("packages",
@@ -101,17 +154,28 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                                                          default="auto"))
             entry.set('type', collection.ptype)
         elif entry.tag == 'Path':
-            if (entry.get("name") == \
-                    self.core.setup.cfp.get("packages",
-                                            "yum_config",
-                                            default=YUM_CONFIG_DEFAULT) or
-                entry.get("name") == \
-                    self.core.setup.cfp.get("packages",
-                                            "apt_config",
-                                            default=APT_CONFIG_DEFAULT)):
-                self.create_config(entry, metadata)
+            self.create_config(entry, metadata)
+        return entry
 
     def HandlesEntry(self, entry, metadata):
+        """ Determine if the given entry can be handled.  Packages
+        handles two kinds of entries:
+
+        * ``Package`` entries are handled if the client has any
+          sources at all.
+        * ``Path`` entries are handled if they match the paths that
+          are handled by a backend that can produce client
+          configurations, e.g., :attr:`YUM_CONFIG_DEFAULT`,
+          :attr:`APT_CONFIG_DEFAULT`, or the overridden value of
+          either of those from the configuration.
+
+        :param entry: The entry to bind
+        :type entry: lxml.etree._Element
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :return: bool - Whether or not this plugin can handle the entry
+        :raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError`
+        """
         if entry.tag == 'Package':
             if self.core.setup.cfp.getboolean("packages", "magic_groups",
                                               default=True):
@@ -134,12 +198,32 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
         return False
 
     def validate_structures(self, metadata, structures):
-        '''Ensure client configurations include all needed prerequisites
-
-        Arguments:
-        metadata - client metadata instance
-        structures - a list of structure-stage entry combinations
-        '''
+        """ Do the real work of Packages.  This does two things:
+
+        #. Given the full list of all packages that apply to this
+           client from the specification, calls
+           :func:`_build_packages` to resolve dependencies, determine
+           unknown packages (i.e., those that are not in any
+           repository that applies to this client), and build a
+           complete package list.
+
+        #. Calls
+           :func:`Bcfg2.Server.Plugins.Packages.Collection._Collection.build_extra_structures`
+           to add any other extra data required by the backend (e.g.,
+           GPG keys)
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :param structures: A list of lxml.etree._Element objects
+                           describing the structures (i.e., bundles)
+                           for this client.  This can be modified in
+                           place.
+        :type structures: list of lxml.etree._Element objects
+        :returns: None
+        """
         collection = self._get_collection(metadata)
         indep = lxml.etree.Element('Independent')
         self._build_packages(metadata, indep, structures,
@@ -149,8 +233,26 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
 
     def _build_packages(self, metadata, independent, structures,
                         collection=None):
-        """ build list of packages that need to be included in the
-        specification by validate_structures() """
+        """ Perform dependency resolution and build the complete list
+        of packages that need to be included in the specification by
+        :func:`validate_structures`, based on the initial list of
+        packages.
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :param independent: The XML tag to add package entries
+                            generated by dependency resolution to.
+                            This will be modified in place.
+        :type independent: lxml.etree._Element
+        :param structures: A list of lxml.etree._Element objects
+                           describing the structures (i.e., bundles)
+                           for this client
+        :type structures: list of lxml.etree._Element objects
+        :param collection: The collection of sources for this client.
+                           If none is given, one will be created with
+                           :func:`_get_collection`
+        :type collection: Bcfg2.Server.Plugins.Packages.Collection._Collection
+        """
         if self.disableResolver:
             # Config requests no resolver
             return
@@ -182,7 +284,7 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                             xml_declaration=False).decode('UTF-8'))
 
         gpkgs = collection.get_groups(groups)
-        for group, pkgs in gpkgs.items():
+        for pkgs in gpkgs.values():
             base.update(pkgs)
 
         base.update(initial | essential)
@@ -200,29 +302,39 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
         collection.packages_to_entry(newpkgs, independent)
 
     def Refresh(self):
-        '''Packages.Refresh() => True|False\nReload configuration
-        specification and download sources\n'''
+        """ Packages.Refresh() => True|False
+
+        Reload configuration specification and download sources """
         self._load_config(force_update=True)
         return True
 
     def Reload(self):
-        '''Packages.Refresh() => True|False\nReload configuration
-        specification and sources\n'''
+        """ Packages.Refresh() => True|False
+
+        Reload configuration specification and sources """
         self._load_config()
         return True
 
     def _load_config(self, force_update=False):
-        '''
+        """
         Load the configuration data and setup sources
 
-        Keyword args:
-            force_update    Force downloading repo data
-        '''
+        :param force_update: Ignore all locally cached and downloaded
+                             data and fetch the metadata anew from the
+                             upstream repository.
+        :type force_update: bool
+        """
         self._load_sources(force_update)
         self._load_gpg_keys(force_update)
 
     def _load_sources(self, force_update):
-        """ Load sources from the config """
+        """ Load sources from the config, downloading if necessary.
+
+        :param force_update: Ignore all locally cached and downloaded
+                             data and fetch the metadata anew from the
+                             upstream repository.
+        :type force_update: bool
+        """
         self.sentinels = set()
         cachefiles = set()
 
@@ -252,7 +364,13 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                                       "%s: %s" % (cfile, err))
 
     def _load_gpg_keys(self, force_update):
-        """ Load gpg keys from the config """
+        """ Load GPG keys from the config, downloading if necessary.
+
+        :param force_update: Ignore all locally cached and downloaded
+                             data and fetch the metadata anew from the
+                             upstream repository.
+        :type force_update: bool
+        """
         keyfiles = []
         keys = []
         for source in self.sources:
@@ -274,18 +392,53 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                 os.unlink(kfile)
 
     def _get_collection(self, metadata):
+        """ Get a
+        :class:`Bcfg2.Server.Plugins.Packages.Collection._Collection`
+        object for this client.
+
+        :param metadata: The client metadata to get a Collection for
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :returns: Bcfg2.Server.Plugins.Packages.Collection._Collection
+        """
         return Collection.Collection(metadata, self.sources, self.data,
                                      debug=self.debug_flag)
 
     def get_additional_data(self, metadata):
+        """ Return additional data for the given client.  This will be
+        a dict containing a single key, ``sources``, whose value is a
+        list of data returned from
+        :func:`Bcfg2.Server.Plugins.Packages.Collection._Collection.get_additional_data`,
+        namely, a list of
+        :attr:`Bcfg2.Server.Plugins.Packages.Source.Source.url_map`
+        data.
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        :return: dict of lists of ``url_map`` data
+        """
         collection = self._get_collection(metadata)
         return dict(sources=collection.get_additional_data())
 
     def end_client_run(self, metadata):
-        """ clear the collection cache for this client, which must
-        persist only the duration of a client run"""
+        """ Hook to clear the cache for this client at
+        :attr:`Bcfg2.Server.Plugins.Packages.Collection.CLIENTS`,
+        which must persist only the duration of a client run.
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        """
         if metadata.hostname in Collection.CLIENTS:
             del Collection.CLIENTS[metadata.hostname]
 
     def end_statistics(self, metadata):
+        """ Hook to clear the cache for this client at
+        :attr:`Bcfg2.Server.Plugins.Packages.Collection.CLIENTS` once
+        statistics are processed to ensure that a stray cached
+        :class:`Bcfg2.Server.Plugins.Packages.Collection._Collection`
+        object is not built during statistics and preserved until a
+        subsequent client run.
+
+        :param metadata: The client metadata
+        :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
+        """
         self.end_client_run(metadata)