added TemplateHelper plugin to easily provide convenience methods to templates

1 files changed, 97 insertions, 0 deletions

diff --git a/examples/TemplateHelper/include.py b/examples/TemplateHelper/include.py
new file mode 100644
index 000000000..5fba75558
--- /dev/null
+++ b/examples/TemplateHelper/include.py
@@ -0,0 +1,97 @@
+"""IncludeHelper makes it easier to include group- and host-specific files in a template.
+
+Synopsis:
+
+  {% python
+  import os
+  include = metadata.TemplateHelper['include'].IncludeHelper
+  custom = include(metadata, path).files(os.path.basename(name))
+  %}\
+  {% for file in custom %}\
+  
+  ########## Start ${include.specificity(file)} ##########
+  {% include ${file} %}
+  ########## End ${include.specificity(file)} ##########
+  {% end %}\
+
+This would let you include files with the same base name; e.g. in a
+template for ''foo.conf'', the include files would be called
+''foo.conf.G_<group>.genshi_include''.  If a template needs to include
+different files in different places, you can do that like so:
+
+  inc = metadata.TemplateHelper['include'].IncludeHelper(metadata, path)
+  custom_bar = inc.files("bar")
+  custom_baz = inc.files("baz")
+
+This would result in two different sets of custom files being used,
+one drawn from ''bar.conf.G_<group>.genshi_include'' and the other
+from ''baz.conf.G_<group>.genshi_include''.
+
+==== Methods ====
+
+
+=== files ===
+
+Usage:
+
+
+
+"""
+
+import os
+import re
+import Bcfg2.Options
+
+__export__ = ["IncludeHelper"]
+
+class IncludeHelper (object):
+    def __init__(self, metadata, path):
+        """ Constructor.
+
+        The template path can be found in the ''path'' variable that is set for all Genshi templates."""
+        self.metadata = metadata
+        self.path = path
+    
+    def _get_basedir(self):
+        setup = Bcfg2.Options.OptionParser({'repo':
+                                            Bcfg2.Options.SERVER_REPOSITORY})
+        setup.parse('--')
+        return os.path.join(setup['repo'], os.path.dirname(self.path))
+    
+    def files(self, fname):
+        """ Return a list of files to include for this host.  Files
+        are found in the template directory based on the following
+        patterns:
+
+          * ''<prefix>.H_<hostname>.genshi_include'': Host-specific files
+          * ''<prefix>.G_<group>.genshi_include'': Group-specific files
+
+        Note that there is no numeric priority on the group-specific
+        files.  All matching files are returned by
+        ''IncludeHelper.files()''. """
+        files = []
+        hostfile = os.path.join(self._get_basedir(),
+                                "%s.H_%s.genshi_include" %
+                                (fname, self.metadata.hostname))
+        if os.path.isfile(hostfile):
+            files.append(hostfile)
+            
+        for group in self.metadata.groups:
+            filename = os.path.join(self._get_basedir(),
+                                    "%s.G_%s.genshi_include" % (fname, group))
+            if os.path.isfile(filename):
+                files.append(filename)
+
+        return sorted(files)
+
+    @staticmethod
+    def specificity(fname):
+        """ Get a string describing the specificity of the given file """
+        match = re.search(r'(G|H)_(.*)\.genshi_include', fname)
+        if match:
+            if match.group(1) == "G":
+                stype = "group"
+            else:
+                stype = "host"
+            return "%s-specific configs for %s" % (stype, match.group(2))
+        return "Unknown specificity"