Healthchecker

Installation

Add this line to your application's Gemfile:

gem 'healthchecker'

And then execute:

$ bundle

Or install it yourself as:

$ gem install healthchecker

Usage

In your config/routes.rb, mount the engine:

Rails.application.routes.draw do
  # ...
  mount Healthchecker::Engine => '/healthchecker'

  # Any wild card end-points
end

With that you will be able to hit:

curl <service_uri>/healthchecker/status which will return 200 with {"status": "ok"} or return 500 with {"status": }

In an initializer such as config/initializers/healthchecker.rb, add your checks. Example:

class CustomHealthcheck < Healthchecker::Check
  def check!
    options[:pass_value] == 'FOO'
  end
end

Healthchecker.add_check(:redis, client: Resque.redis, description: 'Resque.redis')
Healthchecker.add_check(:redis, client: Redis.current, description: 'Some description that will show up in error messages')
Healthchecker.add_check(:database)
Healthchecker.add_check(:migration)
Healthchecker.add_check(:cache)
Healthchecker.add_check(:s3, client: Aws::S3::Client.new(my: :config), buckets: ['my_bucket1', 'my_bucket2'])
Healthchecker.add_check(CustomHealthcheck, pass_value: 'FOO')

Supported Checks:

• redis
  • options: client, redis client - defaults to Redis.new
• database
• migration
• cache
  • options: cache_key, optional - the key to use when checking the cache, defaults to SecureRandom.hex (expires_in 1.second)
• s3
  • options: client, optional - defaults to Aws::S3::Client.new
  • options: buckets, required - list of bucket names to check
  • options: object_key, options - object_key to use when testing read, write, and delete privileges for each bucket. Defaults to healthchecker/#{Time.now.to_i}.json
• solr
  • options: rsolr_client, optional - defaults to default configuration sunspot uses
• dynamodb
  • options: client, optional - defaults to Aws::DynamoDB::Client.new

Note: All checks will return all passed options with failures with the addition of the check specified, by default

Metrics:

curl <service_uri>/healthchecker/metrics which will return a JSON response with selected metrics

In an initializer such as config/initializers/healthchecker.rb, add a configuration block. You can add this block anywhere in the file, though it make most sense before the checks.

Healthchecker.configure do |config|
  config.metrics = [:redis, :sidekiq]
end

# Healthchecker.add_check...
# Healthchecker.add_check...

• config.metrics - Determines which metrics to display in metrics endpoint
  • Defaults to [:redis, :resque]
  • Supported metrics are :redis, :resque, and :sidekiq

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.

TODO:

1. Catch unexpected errors and return them along with the check that produced them
2. Include the check names with the error message along with options

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/Tout/healthchecker.