Add passport cli application for rendering templates

consulate/passport.py

@@ -0,0 +1,60 @@
+"""
+Passport uses the Tornado template engine to render files, injecting values
+from Consul services and kv pairs.
+
+"""
+import argparse
+from os import path
+
+from tornado import template
+
+from consulate import api
+
+
+class Loader(template.Loader):
+
+    def __init__(self, root_directory='/', session=None, **kwargs):
+        super(Loader, self).__init__(root_directory, **kwargs)
+        self.root = root_directory
+        self.session = session
+
+    def _create_template(self, name):
+        value = self.session.kv.get(path.join(self.root, name), None)
+        if value:
+            return template.Template(value, name=name, loader=self)
+        else:
+            raise KeyError
+
+
+class Passport(object):
+
+    def __init__(self, host=api.DEFAULT_HOST, port=api.DEFAULT_PORT, dc=None):
+        self.session = api.Consulate(host, port, dc)
+        self.loader = Loader(session=self.session)
+
+    def render(self, key):
+        t = self.loader.load(key)
+        namespace = {'consul': self.session}
+        return t.generate(**namespace)
+
+    def process(self, key, path):
+        value = self.render(key)
+        with open(path, 'wb') as handle:
+            handle.write(value)
+
+
+def main():
+    parser = argparse.ArgumentParser(description=
+                                         'Render templates from Consul')
+
+    parser.add_argument('-t', '--template', help='The path to the template')
+    parser.add_argument('-d', '--destination',
+                        help='The path to write the rendered template to')
+    args = parser.parse_args()
+    passport = Passport()
+    if passport.process(args.template, args.destination):
+        print('Generated %s' % args.destination)
+
+
+if __name__ == '__main__':
+    main()