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README.md

Orchparty

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Write your own orchestration config with a Ruby DSL that allows you to have mixins, imports and variables.

import "../logging.rb"

application 'my-cool-app' do
  variables do
    var port: 8080
  end

  service "api" do
    mix "logging.syslog"
    image "my-cool-image:latest"
    commad -> { "bundle exec rails s -b 0.0.0.0 -p #{port}" }
  end

end

Why the hell?

1. Powerfull Ruby DSL as a YAML replacement

YAML is great for configuration, it has a clean syntax that is readable for humans as well as machines. In addition it suites for the most of the configurations. Furthermore YAML supports features like referencing, inheritence and multiline Strings.

In our company we have a microservice architecture with multiple applications, which is consisting of multiple services (container types). After a while we have realized that our orchestration configuration were growing continuously and got hell complex, which determine global changes like replacing our logging infrastucture. This changes were quite painfull, because we need to touch every single service.

Some main features for us:

  1. Mixin support
  2. Import from different files
  3. Using variables in imported configs e.g. Stack/Service names

Some of the features are already included in YAML, unfortunately we are not able to use it, because of there complexity.

2. Use Ruby instead of Templating engines

Most of the orchestration frameworks are using a derivative of docker-compose.yml. But most of the users realized that yml is not enough for complex orchestration.

So most of the framework teams started to allow templating engines in the docker-compose configuration.

But why keep going with a data serialization language when we want to program our own configuration?

3. Have one config for multiple orchestration frameworks

How much effort is it to get a application running on an orchestration frameworks? Actually we are glad about finding a prebuild docker-compose file which can be modified by us e.g. for kontena.io, but after modifying for kontena.io we have to redo nearly all the work for rancher, kubernets etc.

It would be really nice, if people starting to write an opensource application config using orchparty and we just simply compile the config for all popular orchestration frameworks.

Installation

Run via docker

Currently only relativ path are supported when running via docker.

Add to bashrc:

  alias orchparty="docker run --rm -v /:/rootfs -e ROOT_PWD=$PWD jannishuebl/orchparty:latest"

As tag you can use semantic versioning eg X.X.X or X.X or X.

If you use latest update by running:

$ docker pull jannishuebl/orchparty:latest

Install from rubygems.org

Setup a Ruby Enviroment with Ruby 2.2 or higher is necessary for the intallation.

$ gem install orchparty

Update:

$ gem update orchparty

Usage

CLI

See the commandline usage instrucution by running:

$ orchparty help

For generating eg. use:

$ orchparty generate docker_compose_v2 -f stack.rb -o docker-compose.yml -a my-cool-app

In your own piece of code

require 'orchparty'

# load the generator plugin you want to use
Orchparty.plugin :docker_compose_v1

Orchparty.generate(:docker_compose_v1,
                     # all options that are needed for orchparty to transform
                     # your input to a plain hash for generating
                    {filename: "path/to/input_file.rb",
                     application: "application_name_to_generate" },
                     # all options that are needed for the plugin
                    {output: "path/to/output_file.yml"})

DSL spec

So let us start an example! Let us implement a configuration for a beautiful app called app_perf with orchparty. This App is an opensource replacement for New Relic!

Applications

app_perf needs the following components:

  • postgres for data storage
  • redis as queuing system
  • web handler as receiver for all metrics
  • worker for processing the metrics and inserting them to the postgres db.
application "app_perf" do

  service "web" do
    image "blasterpal/app_perf"
    command "bundle exec rails s -p 5000"
    expose 5000
    links do 
      link "redis"
      link "postgres"
    end
  end

  service "worker" do
    image "blasterpal/app_perf"
    command "bundle exec sidekiq"
    links do 
      link "redis"
      link "postgres"
    end
  end

  service "redis" do
    image "redis"
  end

  service "postgres" do
    image "postgres"
  end

end

Applevel Mixins

For using external services like RDS from AWS we do not want to ship postgres in a production setup.

mixin "app_perf" do

  service "web" do
    image "blasterpal/app_perf"
    command "bundle exec rails s -p 5000"
    expose 5000
    links do 
      link "redis"
    end
  end

  service "worker" do
    image "blasterpal/app_perf"
    command "bundle exec sidekiq"
    links do 
      link "redis"
    end
  end

  service "redis" do
    image "redis"
  end

end

application 'app_perf-dev' do
  mix "app_perf"

  service "web" do
    links do 
      link "postgres"
    end
  end

  service "worker" do
    links do 
      link "postgres"
    end
  end

  service "postgres" do
    image "postgres"
  end

end

application 'app_perf-prod' do
  mix "app_perf"

  service "web" do
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

  service "worker" do
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

end

Service level Mixin

But we might also mixin a logging config in production.

mixin "logging" do

  service "syslog" do
    logging do 
      conf driver: "syslog"
      options do
        opt syslog-address: "tcp://192.168.0.42:123"
      end
    end
  end

end


application 'app_perf-prod' do
  mix "app_perf"

  service "web" do
    mix "logging.syslog"
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

  service "worker" do
    mix "logging.fluentd"
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

end

Commonblock

Using the all-block for adding configs to all services in one application. Of course the mix "logging.syslog" and environment variables will also added to the redis and postgres service.

application 'app_perf-prod' do
  mix "app_perf"

  all do
    mix "logging.syslog"
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

  service "web" do
  end

  service "worker" do
  end

end

Variables

You want to use variables right? Because "DRY" ;) well you can:

application "app_perf" do
  variables do
    var image: "blasterpal/app_perf"
  end

  service "web" do
    variables do
      # service local variables
    end
    image -> { image }
    command -> { "bundle exec rails s -p #{ service.expose }" }
    expose 5000
    links do 
      link "redis"
      link "postgres"
    end
  end

  service "worker" do
    image -> { image }
    command "bundle exec sidekiq"
    links do 
      link "redis"
      link "postgres"
    end
  end

  service "redis" do
    image "redis"
  end

  service "postgres" do
    image "postgres"
  end

end

special variables:

  1. service: - service.name
  2. application: - application.name

Import

Above we assumed that everything is written in one file. If you do not want to, just use the import feature.

import "../logging.rb"
import "./app_perf.rb"

application 'app_perf-prod' do
  mix "app_perf"

  all do
    mix "logging.syslog"
    environment do
      env POSTGRES_HOST: "rds-domain.amazon.com"
    end
  end

end

Plugins

Orchparty allows you to write own generators via a Plugin system. Also the buildin generators like docker_compose_v1 and docker_compose_v2 generators are only plugins.

To build your own plugin create a ruby gem with a Plugin configuration under lib/orchparty/plugin/#{plugin_name}.rb

Available plugins

  1. orchparty-rancher
  2. orchparty-env

Example Plugin:

module Orchparty
  module Plugin
    class DockerComposeV1

      def self.desc
        # this description is shown in the cli
        "generate docker-compose v1 file"
      end

      def self.define_flags(c)
        # give add all flags that your Generator needs
        # see [davetron5000/gli](https://github.com/davetron5000/gli) for
        # documentatino of flags
        c.flag [:output,:o], required: true, :desc => 'Set the output file'
      end

      def self.generate(application, options)
        # Orchparty will pass the compiled application hash and all options
        # that you required in define_flags.
        # Here is the place where you can write your generation logic
        File.write(options[:output], output(application))
      end

      private
      def self.output(ast)
        ast.services.map do |name, service|
          service = service.to_h
          service.delete(:mix)
          [service.delete(:name), HashUtils.deep_stringify_keys(service.to_h)]
        end.to_h.to_yaml
      end

    end
  end
end

# register your plugin
Orchparty::Plugin.register_plugin(:docker_compose_v1, Orchparty::Plugin::DockerComposeV1)

Plugin Usage:

CLI

The CLI tries to load all plugins that you have installed as gem by using Gem::Specification.

Code

If you use orchparty as part of a own application load a plugin via:

Orchparty.plugin(:docker_compose_v1)

Development

After checking out the repo:

  1. run bin/setup to install dependencies
  2. run rake spec to run the tests You can also run bin/console for an interactive prompt that will allow you to make some experiments.

To install this gem onto your local machine, run bundle exec rake install.

To release a new version:

  1. update the version number in version.rb
  2. run bundle exec rake release which will create a git tag for the version
  3. push git commits and tags and additionally push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/jannishuebl/orchparty. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as opensource project under the terms of the GNU Lesser General Public License v3.0.

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