new GroupLogic plugin

4 files changed, 273 insertions, 1 deletions

diff --git a/doc/server/plugins/connectors/grouplogic.txt b/doc/server/plugins/connectors/grouplogic.txt
new file mode 100644
index 000000000..b9a5b00d6
--- /dev/null
+++ b/doc/server/plugins/connectors/grouplogic.txt
@@ -0,0 +1,122 @@
+.. -*- mode: rst -*-
+
+.. _server-plugins-connectors-grouplogic:
+
+==========
+GroupLogic
+==========
+
+.. versionadded:: 1.3.2
+
+GroupLogic is a connector plugin that lets you use an XML Genshi
+template to dynamically set additional groups for clients.
+
+Usage
+=====
+
+To use the GroupLogic plugin, first do ``mkdir
+/var/lib/bcfg2/GroupLogic``.  Add ``GroupLogic`` to your ``plugins``
+line in ``/etc/bcfg2.conf``.  Next, create
+``/var/lib/bcfg2/GroupLogic/groups.xml``:
+
+.. code-block:: xml
+
+    <GroupLogic xmlns:py="http://genshi.edgewall.org/">
+    </GroupLogic>
+
+``groups.xml`` is structured very similarly to the
+:ref:`server-plugins-grouping-metadata` ``groups.xml``.  A Group tag
+that contains no children is a declaration of membership; a Group or
+Client tag that does contain children is a conditional.
+
+Unlike ``Metadata/groups.xml``, GroupLogic supports genshi templating,
+so you can dynamically create groups.  ``GroupLogic/groups.xml`` is
+rendered for each client, and the groups set in it are added to the
+client metadata.
+
+.. note::
+
+    Also unlike ``Metadata/groups.xml``, GroupLogic can not be used to
+    associate bundles with clients directly, or to negate groups.  But
+    you can use GroupLogic to assign a group that is associated with a
+    bundle in Metadata.
+
+Consider the case where you have four environments -- dev, test,
+staging, and production -- and four components to a web application --
+the frontend, the API, the database server, and the caching proxy.  In
+order to make files specific to the component *and* to the
+environment, you need groups to describe each combination:
+webapp-frontend-dev, webapp-frontend-test, and so on.  You *could* do
+this in ``Metadata/groups.xml``:
+
+.. code-block:: xml
+
+    <Groups>
+      <Group name="webapp-frontend">
+        <Group name="dev">
+          <Group name="webapp-frontend-dev"/>
+        </Group>
+        <Group name="test">
+          <Group name="webapp-frontend-test"/>
+        </Group>
+        ...
+      </Group>
+      <Group name="webapp-api">
+        ...
+      </Group>
+      ...
+    </Groups>
+
+Creating the sixteen groups this way is incredibly tedious, and this
+is a quite *small* site.  GroupLogic can automate this process.
+
+Assume that we've declared the groups thusly in
+``Metadata/groups.xml``:
+
+.. code-block:: xml
+
+    <Groups>
+      <Group name="webapp-frontend" category="webapp-component"/>
+      <Group name="webapp-api" category="webapp-component"/>
+      <Group name="webapp-db" category="webapp-component"/>
+      <Group name="webapp-proxy" category="webapp-component"/>
+      <Group name="dev" category="environment"/>
+      <Group name="test" category="environment"/>
+      <Group name="staging" category="environment"/>
+      <Group name="prod" category="environment"/>
+    </Groups>
+
+One way to automate the creation of the groups would be to simply
+generate the tedious config:
+
+.. code-block:: xml
+
+    <GroupLogic xmlns:py="http://genshi.edgewall.org/">
+      <py:for each="component in metadata.query.all_groups_in_category("webapp-component")>
+        <Group name="${component}">
+          <py:for each="env in metadata.query.all_groups_in_category("environment")>
+            <Group name="${env}">
+              <Group name="${component}-${env}"/>
+            </Group>
+          </py:for>
+        </Group>
+      </py:for>
+    </GroupLogic>
+
+But, since ``GroupLogic/groups.xml`` is rendered for each client
+individually, there's a more elegant way to accomplish the same thing:
+
+.. code-block:: xml
+
+    <GroupLogic xmlns:py="http://genshi.edgewall.org/">
+      <?python
+component = metadata.group_in_category("webapp-component")
+env = metadata.group_in_category("environment")
+      ?>
+      <py:if test="component and env">
+        <Group name="${component}-${env}"/>
+      </py:if>
+    </GroupLogic>
+
+This gets only the component and environment for the current client,
+and, if both are set, sets the single appropriate group.
diff --git a/schemas/grouplogic.xsd b/schemas/grouplogic.xsd
new file mode 100644
index 000000000..bf43bceb3
--- /dev/null
+++ b/schemas/grouplogic.xsd
@@ -0,0 +1,110 @@
+<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+            xmlns:py="http://genshi.edgewall.org/" xml:lang="en">
+
+  <xsd:annotation>
+    <xsd:documentation>
+      GroupLogic schema for bcfg2
+    </xsd:documentation>
+  </xsd:annotation>
+
+  <xsd:import namespace="http://genshi.edgewall.org/"
+              schemaLocation="genshi.xsd"/>
+
+  <xsd:complexType name="GroupLogicDeclarationType">
+    <xsd:annotation>
+      <xsd:documentation>
+        A **GroupLogicDeclarationType** declares a Group to be added
+        to a client.
+      </xsd:documentation>
+    </xsd:annotation>
+    <xsd:attribute type='xsd:string' name='name' use='required'>
+      <xsd:annotation>
+        <xsd:documentation>
+          The group name
+        </xsd:documentation>
+      </xsd:annotation>
+    </xsd:attribute>
+    <xsd:attributeGroup ref="py:genshiAttrs"/>
+  </xsd:complexType>
+
+  <xsd:complexType name="GroupLogicType">
+    <xsd:annotation>
+      <xsd:documentation>
+        The top-level tag of a GroupLogic configuration file.
+      </xsd:documentation>
+    </xsd:annotation>
+    <xsd:choice minOccurs="1" maxOccurs="unbounded">
+      <xsd:group ref="py:genshiElements"/>
+      <xsd:element name='Group' type='GroupLogicDeclarationType'/>
+      <xsd:element name='Group' type='GroupLogicContainerType'>
+        <xsd:annotation>
+          <xsd:documentation>
+            Elements within Group tags only apply to clients that are
+            members of that group (or vice-versa; see #element_negate
+            below)
+          </xsd:documentation>
+        </xsd:annotation>
+      </xsd:element>
+      <xsd:element name='Client' type='GroupLogicContainerType'>
+        <xsd:annotation>
+          <xsd:documentation>
+            Elements within Client tags only apply to the named client
+            (or vice-versa; see #element_negate below)
+          </xsd:documentation>
+        </xsd:annotation>
+      </xsd:element>
+      <xsd:element name='GroupLogic' type='GroupLogicType'>
+        <xsd:annotation>
+          <xsd:documentation>
+            Nesting GroupLogic tags is allowed in order to support
+            XInclude.
+          </xsd:documentation>
+        </xsd:annotation>
+      </xsd:element>
+    </xsd:choice>
+    <xsd:attributeGroup ref="py:genshiAttrs"/>
+  </xsd:complexType>
+
+  <xsd:complexType name="GroupLogicContainerType">
+    <xsd:annotation>
+      <xsd:documentation>
+        A **GroupLogicContainerType** is a tag used to provide logic.
+        Child entries of a GroupLogicContainerType tag only apply to
+        machines that match the condition specified -- either
+        membership in a group, or a matching client name.
+        :xml:attribute:`GroupLogicContainerType:negate` can be set to
+        negate the sense of the match.
+      </xsd:documentation>
+    </xsd:annotation>
+    <xsd:complexContent>
+      <xsd:extension base="GroupLogicType">
+        <xsd:attribute type='xsd:string' name='name' use='required'>
+          <xsd:annotation>
+            <xsd:documentation>
+              The group name
+            </xsd:documentation>
+          </xsd:annotation>
+        </xsd:attribute>
+        <xsd:attribute type='xsd:string' name='negate'>
+          <xsd:annotation>
+            <xsd:documentation>
+              Negate the sense of this group or client; i.e., entries
+              within this tag are only used on clients that are not
+              members of the group, or that have hostnames that do not
+              match.
+            </xsd:documentation>
+          </xsd:annotation>
+        </xsd:attribute>
+      </xsd:extension>
+    </xsd:complexContent>
+  </xsd:complexType>
+
+  <xsd:element name='GroupLogic' type='GroupLogicType'>
+    <xsd:annotation>
+      <xsd:documentation>
+        A GroupLogic file is a genshi file that can be used to
+        dynamically add additional groups to a client.
+      </xsd:documentation>
+    </xsd:annotation>
+  </xsd:element>
+</xsd:schema>
diff --git a/src/lib/Bcfg2/Server/Lint/Validate.py b/src/lib/Bcfg2/Server/Lint/Validate.py
index a5f41c7af..14d17a1e6 100644
--- a/src/lib/Bcfg2/Server/Lint/Validate.py
+++ b/src/lib/Bcfg2/Server/Lint/Validate.py
@@ -40,7 +40,8 @@ class Validate(Bcfg2.Server.Lint.ServerlessPlugin):
              "NagiosGen/config.xml": "nagiosgen.xsd",
              "FileProbes/config.xml": "fileprobes.xsd",
              "SSLCA/**/cert.xml": "sslca-cert.xsd",
-             "SSLCA/**/key.xml": "sslca-key.xsd"
+             "SSLCA/**/key.xml": "sslca-key.xsd",
+             "GroupLogic/groups.xml": "grouplogic.xsd"
              }
 
         self.filelists = {}
diff --git a/src/lib/Bcfg2/Server/Plugins/GroupLogic.py b/src/lib/Bcfg2/Server/Plugins/GroupLogic.py
new file mode 100644
index 000000000..c572fee2b
--- /dev/null
+++ b/src/lib/Bcfg2/Server/Plugins/GroupLogic.py
@@ -0,0 +1,39 @@
+import os
+import lxml.etree
+import Bcfg2.Server.Plugin
+try:
+    from Bcfg2.Server.Plugins.Bundler import BundleTemplateFile
+except ImportError:
+    # BundleTemplateFile missing means that genshi is missing.  we
+    # import genshi to get the _real_ error
+    import genshi  # pylint: disable=W0611
+
+
+class GroupLogicConfig(BundleTemplateFile):
+    create = lxml.etree.Element("GroupLogic",
+                                nsmap=dict(py="http://genshi.edgewall.org/"))
+
+    def __init__(self, name, fam):
+        BundleTemplateFile.__init__(self, name,
+                                    Bcfg2.Server.Plugin.Specificity(), None)
+        self.fam = fam
+        self.should_monitor = True
+        self.fam.AddMonitor(self.name, self)
+
+    def _match(self, item, metadata):
+        if item.tag == 'Group' and not len(item.getchildren()):
+            return [item]
+        return BundleTemplateFile._match(self, item, metadata)
+
+
+class GroupLogic(Bcfg2.Server.Plugin.Plugin,
+                 Bcfg2.Server.Plugin.Connector):
+    def __init__(self, core, datastore):
+        Bcfg2.Server.Plugin.Plugin.__init__(self, core, datastore)
+        Bcfg2.Server.Plugin.Connector.__init__(self)
+        self.config = GroupLogicConfig(os.path.join(self.data, "groups.xml"),
+                                       core.fam)
+
+    def get_additional_groups(self, metadata):
+        return [el.get("name")
+                for el in self.config.get_xml_value(metadata).findall("Group")]