Class: Prometheus::Middleware::Exporter

Inherits:
Object
  • Object
show all
Defined in:
lib/prometheus/middleware/exporter.rb

Overview

Exporter is a Rack middleware that provides a sample implementation of a Prometheus HTTP exposition endpoint.

By default it will export the state of the global registry and expose it under ‘/metrics`. Use the `:registry` and `:path` options to change the defaults.

Constant Summary collapse

FORMATS = 
[Client::Formats::Text].freeze
FALLBACK = 
Client::Formats::Text

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, options = {}) ⇒ Exporter

Returns a new instance of Exporter.



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# File 'lib/prometheus/middleware/exporter.rb', line 20

def initialize(app, options = {})
  @app = app
  @registry = options[:registry] || Client.registry
  @path = options[:path] || '/metrics'
  @acceptable = build_dictionary(FORMATS, FALLBACK)
end

Instance Attribute Details

#app ⇒ Object (readonly)

Returns the value of attribute app.



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# File 'lib/prometheus/middleware/exporter.rb', line 15

def app
  @app
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/prometheus/middleware/exporter.rb', line 15

def path
  @path
end

#registry ⇒ Object (readonly)

Returns the value of attribute registry.



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# File 'lib/prometheus/middleware/exporter.rb', line 15

def registry
  @registry
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/prometheus/middleware/exporter.rb', line 27

def call(env)
  if env['PATH_INFO'] == @path
    format = negotiate(env, @acceptable)
    format ? respond_with(format) : not_acceptable(FORMATS)
  else
    @app.call(env)
  end
end