classicvalues / switchman-inst-jobs

Switchman and Instructure Jobs compatibility gem.

Switchman + Instructure Jobs Compatibility Gem

If you are using the Switchman and Instructure Jobs gems in your application, simply include this gem to make background jobs aware of sharding.

Some high-level features this gem provides to make this work:

• Awareness on the Switchman side (inside shards) that shards have associated DJ shards that need to be activated when trying to talk to the DJ tables (lib/switchman_inst_jobs/switchman)
• Awareness on the DJ side that jobs run within a given shard context that can be loaded from the config and need to activate the shards jobs live on before running (lib/switchman_inst_jobs/delayed)

Requirements

• Ruby 2.3+
• Rails 4.2+

Installation

First ensure that you have installed both Switchman and Instucture Jobs gems, including their database migrations.

Add this line to your application's Gemfile:

gem 'switchman-inst-jobs'

And then execute:

bundle

Or install it yourself like so:

gem install switchman-inst-jobs

You will also want to install the database migration necessary to include the associated shard for any queued jobs:

bundle exec rake switchman_inst_jobs:install:migrations
bundle exec rake db:migrate

You can continue to use inst-jobs settings like you would normally. There is one inst-jobs setting you may want to configure in your application though:

Delayed::Settings.worker_procname_prefix = lambda do
  "#{Switchman::Shard.current(Delayed::Job).id}~"
end

Development

A simple docker environment has been provided for spinning up and testing this gem with multiple versions of Ruby. This requires docker and docker-compose to be installed. To get started, run the following:

docker-compose build --pull
docker-compose up -d postgres
docker-compose run --rm app

This will install the gem in a docker image with all versions of Ruby installed, and install all gem dependencies in the Ruby 2.6 set of gems. It will also download and spin up a PostgreSQL container for use with specs. Finally, it will run wwtd, which runs all specs across all supported version of Ruby and Rails, bundling gems for each combination along the way.

The first build will take a long time, however, docker images and gems are cached, making additional runs significantly faster.

To run individual specs in a development workflow, you're going to want to have your file system mounted into the container:

cp docker-compose.override.example.yml docker-compose.override.yml

Then you're going to want to have a console open so that you can do a fast-feedback loop while making changes:

docker-compose run --rm app /bin/bash -l -c
# you're inside the container shell now
rvm-exec 2.6 bundle install
rvm-exec 2.6 bundle exec rspec
rvm-exec 2.6 bundle exec rspec spec/lib/delayed/worker/health_check_spec.rb

Watch your tests fail, tweak things, run the spec again, etc.

Making a new Release

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 just 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/instructure/switchman-inst-jobs.

License

The gem is available as open source under the terms of the MIT License.