Apply configuration from cloud metadata.
it turns a cloud-metadata file like this:
{"keystone": {"database": {"host": "127.0.0.1", "user": "keystone", "password": "foobar"}}}
into service config files like this:
[sql]
connection = mysql://keystone:[email protected]/keystone
...other settings...
Just pass it the path to a directory tree of templates:
os-config-applier -t /home/me/my_templates
The template directory structure should mimic a root filesystem, and contain templates for only those files you want configured.
e.g.
~/my_templates$ tree
.
└── etc
├── keystone
│ └── keystone.conf
└── mysql
└── mysql.conf
An example tree can be found here.
If a template is executable it will be treated as an executable template. Otherwise, it will be treated as a mustache template.
If you don't need any logic, just some string substitution, use a mustache template.
Metadata settings are accessed with dot ('.') notation:
[sql]
connection = mysql://{{keystone.database.user}}:{{keystone.database.password}@{{keystone.database.host}}/keystone
Configuration requiring logic is expressed in executable templates.
An executable template is a script which accepts configuration as a json string on standard in, and writes a config file to standard out.
The script should exit non-zero if it encounters a problem, so that os-config-applier knows what's up.
The output of the script will be written to the path corresponding to the executable template's path in the template tree.
#!/usr/bin/env ruby
require 'json'
params = JSON.parse STDIN.read
puts "connection = mysql://#{c['keystone']['database']['user']}:#{c['keystone']['database']['password']}@#{c['keystone']['database']['host']}/keystone"
You could even embed mustache in a heredoc, and use that:
#!/usr/bin/env ruby
require 'json'
require 'mustache'
params = JSON.parse STDIN.read
template = <<-eos
[sql]
connection = mysql://{{keystone.database.user}}:{{keystone.database.password}}@{{keystone.database.host}}/keystone
[log]
...
eos
# tweak params here...
puts Mustache.render(template, params)
# install it
sudo pip install -U git+git://github.com/tripleo/os-config-applier.git
# grab example templates
git clone git://github.com/tripleo/openstack-config-templates /tmp/config
# run it
os-config-applier -t /tmp/config/templates/ -m /tmp/config/cfn-init-data.example -o /tmp/config_output