grokify / faraday_middleware-request-retry

module FaradayMiddleware

  module Request

    # Faraday middleware to handle HTTP Status 429 (rate limiting) / 503 (maintenance)

    class Retry < Faraday::Middleware

      attr_reader :retry_util

      def initialize(app, opts = {})

        super app

        @retry_util = FaradayMiddleware::Request::RetryUtil.new opts

      end

      def call(env)

        original_env = env.dup

        response = @app.call env

        retry_status = @retry_util.retry_status response.env[:status], response.env[:response_headers][:retry_after]

        if retry_status

          @app.call original_env

        else

          response

        end

      end

    end

  end

end

module FaradayMiddleware

  module Request

    # Standalone HTTP request retry utility class

    # Can be used outside of FaradayMiddleware, e.g.

    # when Faraday::UploadIO is used

    class RetryUtil

      DEFAULT_ERROR_CODES = [429, 503].freeze

      DEFAULT_RETRY_AFTER = 10

      attr_accessor :error_codes

      attr_accessor :retry_after

      def retry_status(status, this_retry_after = nil)

        return false unless @error_codes.include? status

        seconds_left = (this_retry_after || @retry_after).to_i

        @logger.warn "You have been rate limited. Retrying in #{seconds_left} seconds..." if @logger

        seconds_left.times do |i|

          sleep 1

          time_left = seconds_left - i

          @logger.warn "#{time_left}..." if time_left > 0 && time_left % 5 == 0 && @logger

        end

        @logger.warn 'Retrying...' if @logger

        true

      end

    end

  end

end