Class: Stethoscope

Inherits:
Object
  • Object
show all
Defined in:
lib/stethoscope.rb,
lib/stethoscope/rails.rb,
lib/stethoscope/version.rb

Overview

Adds the heartbeat to the stack

Defined Under Namespace

Classes: Buckets, Railtie

Constant Summary collapse

VERSION = 
"0.2.3"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Stethoscope

Returns a new instance of Stethoscope.



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# File 'lib/stethoscope.rb', line 132

def initialize(app)
  @app = app
end

Class Method Details

.buckets ⇒ Object 



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# File 'lib/stethoscope.rb', line 32

def self.buckets
  @buckets
end

.check(name, *_buckets_, &blk) ⇒ Object

Add a check to Stethoscope

A check is a block that checks the health of some aspect of your application You add information to the response of the check, including a status (if not successful)

Any resonse that has a status outside 200..299 will cause the heartbeat to fail

Examples:

Stethoscope.check("My Database") do |response|
  if my_db_check
    response[:result] = "Success"
  else
    response[:result] = "Bad Bad Bad"
    response[:arbitrary] = "something else"
    response[:status] = 500 # <---- VERY IMPORTANT
  end
end

See Also:



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# File 'lib/stethoscope.rb', line 83

def self.check(name, *_buckets_, &blk)
  _buckets_.each do |bucket|
    buckets[bucket] << name
  end
  checks[name] = blk
end

.checks ⇒ Object

The collection of checks currently in place in Stethoscope

See Also:



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# File 'lib/stethoscope.rb', line 59

def self.checks
  @checks ||= {}
end

.clear_checks ⇒ Object

Clears all defined checks

See Also:



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# File 'lib/stethoscope.rb', line 106

def self.clear_checks
  buckets.clear
  checks.clear
end

.remove_check(name) ⇒ Object

Removes a give check

Examples:

Stethoscope.remove_check("my check to remove")

See Also:



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# File 'lib/stethoscope.rb', line 96

def self.remove_check(name)
  buckets.each do |bucket, _checks_|
    _checks_.delete(name)
  end
  checks.delete(name)
end

.template ⇒ Object

Getter for the Tilt template for heartbeat rendering By default, the Stethoscope default template is used. Overwrite this to use a custom template

See Also:



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# File 'lib/stethoscope.rb', line 129

def self.template
  @template ||= Tilt.new(File.join(File.dirname(__FILE__), "stethoscope", "template.erb"))
end

.template=(template) ⇒ Object

Sets the Tilt template that will be used for heartbeat rendering

Parameters:

  • template —

    • A Tilt template object

See Also:



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# File 'lib/stethoscope.rb', line 118

def self.template=(template)
  @template = template
end

.url ⇒ Object

The current url that Stethoscope is setup to listen for

See Also:



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# File 'lib/stethoscope.rb', line 52

def self.url
  @url ||= "/heartbeat"
end

.url=(url) ⇒ Object

Set the url to check for the heartbeat in this application

Examples:

Stethoscope.url = "/my/heartbeat/location"

GET "/my/heartbeat/location" <-- intercepted by stethoscope

See Also:



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# File 'lib/stethoscope.rb', line 45

def self.url=(url)
  @url = url
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/stethoscope.rb', line 136

def call(env)
  request = Rack::Request.new(env)
  return @app.call(env) unless check_heartbeat?(request.path)
  responses = Hash.new do |h,k|
    h[k] = {:status => 200}
  end

  _checks_ = checks_to_run(request.path)

  _checks_.each do |name, check|
    begin
      check.call(responses[name])
    rescue => e
      responses[name][:error]  = e
      responses[name][:status] = 500
    end
  end

  status = responses.any?{ |k,v| v[:status] && !((200..299).include?(v[:status])) } ? 500 : 200
  _format = format(request.path)

  headers = { 'Content-Type' => 'text/html' }

  case format(request.path)
  when :html
    result = Stethoscope.template.render(Object.new, :checks => responses)
  when :json
    result = {:checks => responses, :status => status}.to_json
    headers['Content-Type'] = 'application/json'
  end

  Rack::Response.new(result, status, headers).finish
end