Class: Circuitbox::FaradayMiddleware

Inherits:
Faraday::Middleware
  • Object
show all
Defined in:
lib/circuitbox/faraday_middleware.rb

Defined Under Namespace

Classes: NullResponse, RequestFailed

Constant Summary collapse

DEFAULT_OPTIONS = 
{
  open_circuit: lambda do |response|
    # response.status:
    # nil -> connection could not be established, or failed very hard
    # 5xx -> non recoverable server error, opposed to 4xx which are client errors
    response.status.nil? || (response.status >= 500 && response.status <= 599)
  end,
  default_value: ->(service_response, exception) { NullResponse.new(service_response, exception) },
  # It's possible for the URL object to not have a host at the time the middleware
  # is run. To not break circuitbox by creating a circuit with a nil service name
  # we can get the string representation of the URL object and use that as the service name.
  identifier: ->(env) { env[:url].host || env[:url].to_s },
  # default circuit breaker options are merged in during initialization
  circuit_breaker_options: {}
}.freeze
DEFAULT_EXCEPTIONS = 
[
  Faraday::TimeoutError,
  RequestFailed
].freeze
DEFAULT_CIRCUIT_BREAKER_OPTIONS = 
{
  exceptions: DEFAULT_EXCEPTIONS
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize(app, opts = {}) ⇒ FaradayMiddleware

Returns a new instance of FaradayMiddleware.



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# File 'lib/circuitbox/faraday_middleware.rb', line 45

def initialize(app, opts = {})
  @app = app
  @opts = DEFAULT_OPTIONS.merge(opts)

  @opts[:circuit_breaker_options] = DEFAULT_CIRCUIT_BREAKER_OPTIONS.merge(@opts[:circuit_breaker_options])
  super(app)
end

Instance Method Details

#call(request_env) ⇒ Object 



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# File 'lib/circuitbox/faraday_middleware.rb', line 53

def call(request_env)
  service_response = nil
  circuit(request_env).run do
    @app.call(request_env).on_complete do |env|
      service_response = Faraday::Response.new(env)
      raise RequestFailed if open_circuit?(service_response)
    end
  end
rescue Circuitbox::Error => e
  circuit_open_value(request_env, service_response, e)
end