doctor-strange

Doctor Strange

Monitoring various services (db, cache, sidekiq/resque, email, redis, payment, etc).

Examples

HTML Status Page

JSON Response

>> curl -s http://localhost:3000/check.json | json_pp

{
	"results": [{
		"name": "Database",
		"message": "",
		"status": "OK"
	}, {
		"name": "Redis",
		"message": "",
		"status": "OK"
	}, {
		"name": "Sidekiq",
		"message": "",
		"status": "OK"
	}, {
		"name": "Email",
		"message": "",
		"status": "OK"
	}, {
		"name": "Payment",
		"message": "",
		"status": "OK"
	}],
	"status": "ok",
	"timestamp": "2018-03-12 16:36:55 +0800"
}

XML Response

>> curl -s http://localhost:3000/check.xml

<?xml version="1.0" encoding="UTF-8"?>
<hash>
  <results type="array">
    <result>
      <name>Database</name>
      <message />
      <status>OK</status>
    </result>
    <result>
      <name>Redis</name>
      <message />
      <status>OK</status>
    </result>
    <result>
      <name>Sidekiq</name>
      <message />
      <status>OK</status>
    </result>
    <result>
      <name>Email</name>
      <message />
      <status>OK</status>
    </result>
    <result>
      <name>Payment</name>
      <message />
      <status>OK</status>
    </result>
  </results>
  <status type="symbol">ok</status>
  <timestamp>2018-03-12 16:38:31 +0800</timestamp>
</hash>

Setup

If you are using bundler add doctor-strange to your Gemfile:

gem 'doctor-strange'

Then run:

$ bundle install

Otherwise install the gem:

$ gem install doctor-strange

Usage

You can mount this inside your app routes by adding this to config/routes.rb:

mount DoctorStrange::Engine, at: '/'

Supported Service Providers

The following services are currently supported:

• DB
• Cache
• Redis
• Sidekiq
• Resque
• Stripe
• MailGun

Configuration

Adding AppName

The app name is SiliconJungles by default. You can change to your app name.

DoctorStrange.configure do |config|
  config.app_name = "YOUR_APP_NAME"
end

Adding Providers

By default, only the database check is enabled. You can add more service providers by explicitly enabling them via an initializer:

DoctorStrange.configure do |config|
  config.cache
  config.redis
  config.sidekiq
  # etc
end

We believe that having the database check enabled by default is very important, but if you still want to disable it (e.g., if you use a database that isn't covered by the check) - you can do that by calling the no_database method:

DoctorStrange.configure do |config|
  config.no_database
end

Provider Configuration

Some of the providers can also accept additional configuration:

# Sidekiq
DoctorStrange.configure do |config|
  config.sidekiq.configure do |sidekiq_config|
    sidekiq_config.latency = 3.hours
    sidekiq_config.queue_size = 50
  end
end

# Redis
DoctorStrange.configure do |config|
  config.redis.configure do |redis_config|
    redis_config.connection = Redis.current # use your custom redis connection
    redis_config.url = 'redis://user:[e-mail]:90210/' # or URL
    redis_config.max_used_memory = 200 # Megabytes
  end
end

# Email - MailGun by default
DoctorStrange.configure do |config|
  config.email.configure do |email_config|
    email_config.api_key = "abcd"
    email_config.domain = "foo.bar"
  end
end

# Payment - Stripe by default
DoctorStrange.configure do |config|
  config.payment.configure do |payment_config|
    payment_config.api_key = "sk_live_xxxxx"
  end
end

The currently supported settings are:

Sidekiq

• latency: the latency (in seconds) of a queue (now - when the oldest job was enqueued) which is considered unhealthy (the default is 30 seconds, but larger processing queue should have a larger latency value).
• queue_size: the size (maximim) of a queue which is considered unhealthy (the default is 100).

Redis

• url: the url used to connect to your Redis instance - note, this is an optional configuration and will use the default connection if not specified
• connection: Use custom redis connection (e.g., Redis.current).
• max_used_memory: Set maximum expected memory usage of Redis in megabytes. Prevent memory leaks and keys overstore.

Email

• Default transaction email service for now is MailGun.

• api_key: the mail service api_key - this is a required value and will return unhealthy if not specified
• domain: the mail service domain value - this is a required value and will return unhealthy if not specified.

Payment

• Default payment service for now is Stripe.

• api_key: The Payment service's api_key - returns unhealthy if not specified or invalid.

Adding a Custom Provider

It's also possible to add custom health check providers suited for your needs (of course, it's highly appreciated and encouraged if you'd contribute useful providers to the project).

In order to add a custom provider, you'd need to:

• Implement the DoctorStrange::Providers::Base class and its check! method (a check is considered as failed if it raises an exception):

class CustomProvider < DoctorStrange::Providers::Base
  def check!
    raise 'Oh oh!'
  end
end

• Add its class to the configuration:

DoctorStrange.configure do |config|
  config.add_custom_provider(CustomProvider)
end

Adding a Custom Error Callback

If you need to perform any additional error handling (for example, for additional error reporting), you can configure a custom error callback:

DoctorStrange.configure do |config|
  config.error_callback = proc do |e|
    logger.error "Health check failed with: #{e.message}"

    Raven.capture_exception(e)
  end
end

Adding Authentication Credentials

By default, the /check endpoint is not authenticated and is available to any user. You can authenticate using HTTP Basic Auth by providing authentication credentials:

DoctorStrange.configure do |config|
  config.basic_auth_credentials = {
    username: 'SECRET_NAME',
    password: 'Shhhhh!!!'
  }
end

Adding Environment Variables

By default, environment variables is nil, so if you'd want to include additional parameters in the results JSON, all you need is to provide a Hash with your custom environment variables:

DoctorStrange.configure do |config|
  config.environment_variables = {
    build_number: 'BUILD_NUMBER',
    git_sha: 'GIT_SHA'
  }
end

TODO

• Support another transaction Email services such as: SES, Mandrill by MailChimp, SendGird, AliCloud's DirectMail, etc.

• Support another payment services such as: Adyen, Braintree, etc.

License

The MIT License (MIT)

Copyright (c) 2018

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.