Added docs and made template filename variable

Changed how jinja ENV is created
Added docstrings to functions in template.py
Renamed _location_types private attribute of
 SingleInstanceConfigTemplate to _config_paths
SingleInstanceConfigTemplate constructor now uses filename based on
 service type
SingleInstanceConfigTemplate render method now returns the result
Tests updated to use new style of render method
mysql.config.template duplicated to percona.config.template

implements blueprint redis-servicetype

Change-Id: Id9317b560236d5d4967b888d0dc3a4135f1822dc

1 files changed, 25 insertions, 20 deletions

diff --git a/trove/common/template.py b/trove/common/template.py
index dafc626b..df5dc4e6 100644
--- a/trove/common/template.py
+++ b/trove/common/template.py
@@ -12,35 +12,40 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-_ENV = None
-
 import jinja2
 
-
-def get_env():
-    global _ENV
-    if not _ENV:
-        _ENV = create_env()
-    return _ENV
+ENV = jinja2.Environment(loader=jinja2.ChoiceLoader([
+    jinja2.FileSystemLoader("/etc/trove/templates"),
+    jinja2.PackageLoader("trove", "templates")
+]))
 
 
-def create_env():
-    loader = jinja2.ChoiceLoader([
-        jinja2.FileSystemLoader("/etc/trove/templates"),
-        jinja2.PackageLoader("trove", "templates")
-    ])
-    return jinja2.Environment(loader=loader)
+class SingleInstanceConfigTemplate(object):
+    """ This class selects a single configuration file by database type for
+    rendering on the guest """
+    _config_paths = {'mysql': '/etc/mysql/my.cnf',
+                     'percona': '/etc/mysql/my.cnf'}
 
+    def __init__(self, service_type, flavor_dict):
+        """ Constructor
 
-class SingleInstanceConfigTemplate(object):
-    _location_types = {'mysql': '/etc/mysql/my.cnf',
-                       'percona': '/etc/mysql/my.cnf'}
+        :param service_type: The database type.
+        :type name: str.
+        :param flavor_dict: dict containing flavor details for use in jinja.
+        :type flavor_dict: dict.
 
-    def __init__(self, location_type, flavor_dict):
-        self.config_location = self._location_types[location_type]
+        """
+        self.config_location = self._config_paths[service_type]
         self.flavor_dict = flavor_dict
-        self.template = get_env().get_template("mysql.config.template")
+        template_filename = "%s.config.template" % service_type
+        self.template = ENV.get_template(template_filename)
 
     def render(self):
+        """ Renders the jinja template
+
+        :returns: str -- The rendered configuration file
+
+        """
         self.config_contents = self.template.render(
             flavor=self.flavor_dict)
+        return self.config_contents