NjiuStatus

This gem provides a Rack application that supplies the basic structure for diagnostic endpoints. It's meant to be mounted within a Rails application.

Installation

Add this line to your application's Gemfile:

gem "njiu_status", git: "git@github.com:njiuko/njiu_status.git"

Setup

Mount the Rack application in your routes file.

mount NjiuStatus::RackApp, at: "status"

Define endpoints (checks) that should be available under the mount point and restrict access to them by setting a token. ProTip: Put this into an initializer.

NjiuStatus.configure do |config|
  config.token = "foobar123"
end

NjiuStatus.add_check name: "users", handler: -> (request, response) do
  begin
    response.write({users: User.first.name}.to_json)
    response.status = 200
  rescue NoMethodError
    response.write({error: "No users in database."}.to_json)
    response.status = 500
  end
end

NjiuStatus.add_check name: "posts", handler: -> (request, response) do
  if Post.failed.any?
    response.write({error: "There a failed posts."}.to_json)
    response.status = 418
  else
    response.status = 200
  end
end

# example for usage with nagios plugin 'check_json.rb'
NjiuStatus.add_check name: "nagios", handler: -> (request, response) do
  if SystemCheck.ok?
    response.write({message: "Everything went better than expected :)", exit_code: NjiuStatus::EXIT_OK}.to_json)
  elsif SystemCheck.failed?
    response.write({message: "Something went terribly wrong.", exit_code: NjiuStatus::EXIT_CRITICAL}.to_json)
  elsif SystemCheck.high_load?
    response.write({message: "It's gettin' hot in here.", exit_code: NjiuStatus::EXIT_WARNING}.to_json)
  end
end

Usage

The example above generates the following routes:

/status/users
/status/posts
/status/nagios

If a token was configured it has to be supplied in every call either via a HTTP header (preferred) or as a query param.

curl -I -H"Authorization: Token foobar123" http://localhost:3000/status/users

curl -I http://localhost:3000/status/users?token=foobar123

Within a check each handler has access to the current request and should set the body and status in the response.

The gem provides basic error handling if an exception is raised within the handler. Nevertheless: each check should rescue possible exceptions itself and always return a valid response.

Development & Testing

Install all necessary dependencies:

bundle
appraisal install

Run specs without integration tests:

rspec

Run specs with integrations tests for Rails 3 and Rails 4:

appraisal rspec