Move throttling feature from gem back to the app

app/lib/shunter.rb

@@ -0,0 +1,27 @@
+module Shunter
+  module_function
+
+  class ThrottleError < StandardError; end
+
+  BASE_LOGGER = ::Logger.new($stdout)
+  ONE_MINUTE = 60
+  ONE_HUNDRED_REQUESTS = 100
+
+  BASE_CONNECTION = ENV['shunter_redis_connection'] || { host: 'redis', port: 6379 }
+
+  def default_timespan
+    ENV['shunter_default_timespan'] || ONE_MINUTE
+  end
+
+  def default_threshold
+    ENV['shunter_default_threshold'] || ONE_HUNDRED_REQUESTS
+  end
+
+  def default_adapter
+    ENV['shunter_default_adapter'] || 'Shunter::Adapters::Redis'
+  end
+
+  def feature_enabled?
+    ActiveModel::Type::Boolean.new.cast(ENV['shunter_enabled'] || 'false')
+  end
+end

app/lib/shunter/adapters/memory.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Shunter
+  module Adapters
+    class Memory
+      attr_reader :store
+
+      def initialize(_options = {})
+        @@store ||= {}
+      end
+
+      def find_counter(key)
+        @@store[key]
+      end
+
+      def write_counter(key)
+        @@store[key] = 1
+      end
+
+      def increment_counter(key)
+        @@store[key] += 1
+      end
+
+      def clear!
+        @@store = {}
+      end
+
+      def expire_counter(_key, _timespan); end
+    end
+  end
+end

app/lib/shunter/adapters/redis.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Shunter
+  module Adapters
+    class Redis
+      attr_reader :redis
+
+      def initialize(options)
+        @redis = ::Redis.new(options)
+      end
+
+      def find_counter(key)
+        @redis.get(key)
+      end
+
+      def write_counter(key)
+        @redis.set(key, 1)
+      end
+
+      def increment_counter(key)
+        @redis.incr(key)
+      end
+
+      def expire_counter(key, timespan)
+        @redis.expire(key, timespan)
+      end
+    end
+  end
+end

app/lib/shunter/base.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module Shunter
+  class Base
+    attr_accessor :user_id, :adapter
+
+    def initialize(options = {})
+      @user_id = options[:user_id]
+      adapter_klass = Shunter.default_adapter.constantize
+      @adapter = adapter_klass.new(options[:conn_options])
+    end
+
+    def user_key
+      "counting_#{@user_id}"
+    end
+
+    def blocked_user_key
+      "blocked_#{@user_id}"
+    end
+
+    def throttle
+      return false if blocked?
+
+      valid_counter?
+    end
+
+    def blocked?
+      adapter.find_counter(blocked_user_key).present?
+    end
+
+    def valid_counter?
+      if adapter.find_counter(user_key)
+        number_of_requests = adapter.increment_counter(user_key)
+        if number_of_requests > allowed_requests.to_i
+          init_counter(blocked_user_key)
+          return false
+        end
+      else
+        init_counter(user_key)
+      end
+      true
+    end
+
+    private
+
+    def init_counter(key)
+      adapter.write_counter(key)
+      adapter.expire_counter(key, timespan)
+    end
+
+    def allowed_requests
+      Shunter.default_threshold
+    end
+
+    def timespan
+      Shunter.default_timespan
+    end
+
+    def logger
+      Shunter::BASE_LOGGER
+    end
+  end
+end

app/lib/shunter/integration/throttle.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require 'active_support/concern'
+
+module Shunter
+  module Integration
+    module Throttle
+      extend ActiveSupport::Concern
+
+      included do |base|
+        actions = base.const_defined?('THROTTLED_ACTIONS') && base.const_get('THROTTLED_ACTIONS')
+        return if actions.blank?
+
+        around_action :throttle, only: actions
+
+        def throttle
+          unless throttled_user.present? && Shunter.feature_enabled?
+            yield if block_given?
+            return
+          end
+
+          user_id = throttled_user.id
+
+          shunter = Shunter::Base.new(conn_options: connection_options, user_id: user_id)
+          if shunter.throttle
+            logger.info "Request from #{throttled_user.class}/#{throttled_user.id} is coming through throttling"
+            yield if block_given?
+          else
+            logger.info "Too many requests from #{throttled_user.class}/#{throttled_user.id}."
+            raise Shunter::ThrottleError
+          end
+        end
+      end
+
+      def connection_options
+        Shunter::BASE_CONNECTION
+      end
+
+      def logger
+        Shunter::BASE_LOGGER
+      end
+    end
+  end
+end