Experimental Platform SKVS - Ruby Client

This is a ruby client for the Simple Key Value Service used for storing and querying configuration on Experimental Platform

Installation

Install with gem install platform-skvs or add it to your Gemfile.

Usage

You get a simple get/set/del interface for keys and values:

SKVS.get 'foo' #=> nil
SKVS.set 'foo', 'bar'
SKVS.get 'foo' #=> 'bar'
SKVS.del 'foo'
SKVS.get 'foo' #=> nil

There is also the SKVS.try method, which includes polling for a success/error feedback from any service dependent on the key you are setting. Imagine for example a system service that, when the hostname key changes, does some adjustments to your host machine. If you want feedback on the success of this operation, you would call `SKVS.try 'hostname', 'albatross', success: 'hostname/success', error: 'hostname/success', which will do the following:

• Remove any existing error/success values under the given keys
• Fetch the current hostname value
• Set the new hostname value
• Query the error/success keys until a value shows up under one of them
• Return a Ruby object that responds either to success with 'Value of the success key' or to error with 'Value of the error key a.k.a. error message'
• On error, it will set the hostname back to the original value

This is a simple way to get synchronous feedback on asynchronous operations. Obviously, you will need to make sure the service handling your hostname will correctly populate it's success and error keys for this to work.

Adapters

The default adapter is the regular HTTPAdapter that will interact with the SKVS API, which is assumed to be linked into a docker container under the hostname skvs.

For development and testing, it will make much more sense to use the MemoryAdapter, which simply uses a Ruby hash for local storage.

You can swap adapters with SKVS.adapter = SKVS::MemoryAdapter.new, so for example to configure your RSpec test suite to always use the memory adapter, your spec_helper would need this:

RSpec.configure do |config|
  config.before(:each) do
    SKVS.adapter = SKVS::MemoryAdapter.new
  end
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/experimental-platform/platform-skvs-ruby.