Addresses minor issues related to PR #274: (#276)

- Eliminated unnecessary directory walk in init_template()
Other:
- Fixed bug in validate_template(), i.e., dereferencing non-existent
  'id' member when cluster_template_d field is undefined
- Clarification of 'devices' file usage in templates/README.md

conf/templates/README.md

@@ -122,7 +122,8 @@ automatically by simply adding them to the **ec2** section of
 
 The *devices* file contains the user-defined mapping of storage
 devices and mount points for all data (i.e., non-root) volumes in your
-cluster.
+cluster. Muchos Ansible scripts leverage this information to prepare
+all data volumes during the cluster `setup` phase.
 
 Two (and only two) device mappings should exist within *devices*:
 * One map to represent your **worker** device mounts, and

conf/templates/user/.gitignore

@@ -1 +1 @@
-*
+*

lib/muchos/config.py

@@ -339,21 +339,14 @@ def print_property(self, key):
  exit("Property '{0}' was not found".format(key))
 
  def init_template(self, templates_path):
- if not self.has_option('ec2', 'cluster_template'):
- return
-
- template_id = self.get('ec2', 'cluster_template')
- for root, dirs, files in os.walk(templates_path):
- for dir_name in dirs:
- if dir_name == template_id:
- self.cluster_template_d = {'id': template_id}
- template_dir = os.path.join(root, dir_name)
- self.load_template_ec2_requests(template_dir)
- self.load_template_device_map(template_dir)
- break
- break
-
- self.validate_template()
+ if self.has_option('ec2', 'cluster_template'):
+ template_id = self.get('ec2', 'cluster_template')
+ template_path = os.path.join(templates_path, template_id)
+ if os.path.exists(template_path):
+ self.cluster_template_d = {'id': template_id}
+ self.load_template_ec2_requests(template_path)
+ self.load_template_device_map(template_path)
+ self.validate_template()
 
  def load_template_ec2_requests(self, template_dir):
  for json_path in glob.glob(os.path.join(template_dir, '*.json')):
@@ -374,7 +367,7 @@ def load_template_device_map(self, template_dir):
 
  def validate_template(self):
  if not self.cluster_template_d:
- exit("ERROR - Template '{0}' is not defined!".format(self.cluster_template_d['id']))
+ exit("ERROR - Template '{0}' is not defined!".format(self.get('ec2', 'cluster_template')))
 
  if 'worker' not in self.cluster_template_d:
  exit("ERROR - '{0}' template config is invalid. No 'worker' launch request is defined".format(