Ohai detects data about your operating system. It can be used standalone, but its primary purpose is to provide node data to Chef.

Ohai will print out a JSON data blob for all the known data about your system. When used with Chef, that data is reported back via node attributes.

Opscode distributes ohai as a RubyGem. This README is for developers who want to modify the Ohai source code. For users who want to write plugins for Ohai, see the wiki:

• wiki.opscode.com/display/chef/Ohai

Before working on the code, if you plan to contribute your changes, you need to read the Opscode Contributing document.

• wiki.opscode.com/display/chef/How+to+Contribute

You will also need to set up the repository with the appropriate branches. We document the process on the Chef Wiki.

• wiki.opscode.com/display/chef/Working+with+git

(Substitute ‘ohai’ for ‘chef’ in the instructions.)

Once your repository is set up, you can start working on the code. We do use BDD/TDD with RSpec, and soon Cucumber for integration/feature testing, so you’ll need to get those installed.

In order to have a dev environment where you can work on Ohai, you’ll need to install a few additional gems after setting up the Git repository. This is easily done using the Bundler gem:

gem install bundler
bundle install

Note that Bundler requires commands belonging to the gems it manages be run with +bundle exec+, so Rake would need to be run with +bundle exec rake+ in the examples below.

Ohai has some Rake tasks for doing various things.

rake -T
rake clobber_package  # Remove package products
rake clobber_rdoc     # Remove RDoc HTML files
rake gem              # Build the gem file ohai-$VERSION.gem
rake install          # install the gem locally
rake package          # Build all the packages
rake rdoc             # Build RDoc HTML files
rake repackage        # Force a rebuild of the package files
rake rerdoc           # Rebuild RDoc HTML files
rake spec             # Run RSpec code examples

($VERSION is the current version, from lib/ohai/version.rb)

We use RSpec for unit/spec tests. The Rake task spec is run by default when no other task is specified. These two lines are equivalent:

rake
rake spec

Because Ohai gathers system information, and we don’t know what kind of system we might be running on (yet), we’re moving away from specs toward Cucumber “features” for integration testing.

Source:

• github.com/opscode/ohai/tree/master

Tickets/Issues:

• tickets.opscode.com/browse/OHAI

Documentation:

• wiki.opscode.com/display/chef/Ohai

Ohai - system information application

Author

Adam Jacob (<[email protected]>)

Copyright

Copyright © 2008 Opscode, Inc.

License

Apache License, Version 2.0

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at: www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.