feat: Log and Handle Error for Event Dispatcher response (#221)

* WIP

* finalize

Author: oakbani

lib/optimizely.rb

@@ -70,7 +70,7 @@ def initialize(
     )
       @logger = logger || NoOpLogger.new
       @error_handler = error_handler || NoOpErrorHandler.new
-      @event_dispatcher = event_dispatcher || EventDispatcher.new
+      @event_dispatcher = event_dispatcher || EventDispatcher.new(logger: @logger, error_handler: @error_handler)
       @user_profile_service = user_profile_service
 
       begin
@@ -701,7 +701,7 @@ def validate_instantiation_options
 
       return if Helpers::Validator.event_dispatcher_valid?(@event_dispatcher)
 
-      @event_dispatcher = EventDispatcher.new
+      @event_dispatcher = EventDispatcher.new(logger: @logger, error_handler: @error_handler)
       raise InvalidInputError, 'event_dispatcher'
     end
 

lib/optimizely/event/batch_event_processor.rb

@@ -37,15 +37,15 @@ class BatchEventProcessor < EventProcessor
 
     def initialize(
       event_queue: SizedQueue.new(DEFAULT_QUEUE_CAPACITY),
-      event_dispatcher: Optimizely::EventDispatcher.new,
+      event_dispatcher: nil,
       batch_size: DEFAULT_BATCH_SIZE,
       flush_interval: DEFAULT_BATCH_INTERVAL,
       logger: NoOpLogger.new,
       notification_center: nil
     )
       @event_queue = event_queue
       @logger = logger
-      @event_dispatcher = event_dispatcher
+      @event_dispatcher = event_dispatcher || EventDispatcher.new(logger: @logger)
       @batch_size = if (batch_size.is_a? Integer) && positive_number?(batch_size)
                       batch_size
                     else

lib/optimizely/event_dispatcher.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 #
-#    Copyright 2016-2017, Optimizely and contributors
+#    Copyright 2016-2017, 2019, Optimizely and contributors
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
 #    See the License for the specific language governing permissions and
 #    limitations under the License.
 #
+require_relative 'exceptions'
+
 require 'httparty'
 
 module Optimizely
@@ -28,26 +30,46 @@ class EventDispatcher
     # @api constants
     REQUEST_TIMEOUT = 10
 
+    def initialize(logger: nil, error_handler: nil)
+      @logger = logger || NoOpLogger.new
+      @error_handler = error_handler || NoOpErrorHandler.new
+    end
+
     # Dispatch the event being represented by the Event object.
     #
     # @param event - Event object
     def dispatch_event(event)
       if event.http_verb == :get
-        begin
-          HTTParty.get(event.url, headers: event.headers, query: event.params, timeout: REQUEST_TIMEOUT)
-        rescue Timeout::Error => e
-          return e
-        end
+        response = HTTParty.get(event.url, headers: event.headers, query: event.params, timeout: REQUEST_TIMEOUT)
+
       elsif event.http_verb == :post
-        begin
-          HTTParty.post(event.url,
-                        body: event.params.to_json,
-                        headers: event.headers,
-                        timeout: REQUEST_TIMEOUT)
-        rescue Timeout::Error => e
-          return e
-        end
+        response = HTTParty.post(event.url,
+                                 body: event.params.to_json,
+                                 headers: event.headers,
+                                 timeout: REQUEST_TIMEOUT)
       end
+
+      error_msg = "Event failed to dispatch with response code: #{response.code}"
+
+      case response.code
+      when 400...500
+        @logger.log(Logger::ERROR, error_msg)
+        @error_handler.handle_error(HTTPCallError.new("HTTP Client Error: #{response.code}"))
+
+      when 500...600
+        @logger.log(Logger::ERROR, error_msg)
+        @error_handler.handle_error(HTTPCallError.new("HTTP Server Error: #{response.code}"))
+      end
+    rescue Timeout::Error => e
+      @logger.log(Logger::ERROR, "Request Timed out. Error: #{e}")
+      @error_handler.handle_error(e)
+
+      # Returning Timeout error to retain existing behavior.
+      e
+    rescue StandardError => e
+      @logger.log(Logger::ERROR, "Event failed to dispatch. Error: #{e}")
+      @error_handler.handle_error(e)
+      nil
     end
   end
 end

lib/optimizely/exceptions.rb

@@ -18,6 +18,13 @@
 module Optimizely
   class Error < StandardError; end
 
+  class HTTPCallError < Error
+    # Raised when a 4xx or 5xx response code is recieved.
+    def initialize(msg = 'HTTP call resulted in a response with an error code.')
+      super
+    end
+  end
+
   class InvalidAudienceError < Error
     # Raised when an invalid audience is provided
 

spec/event_dispatcher_spec.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 #
-#    Copyright 2016-2017, Optimizely and contributors
+#    Copyright 2016-2017, 2019, Optimizely and contributors
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -16,11 +16,13 @@
 #    limitations under the License.
 #
 require 'spec_helper'
-require 'webmock'
-require 'optimizely/event_builder'
 require 'optimizely/event_dispatcher'
+require 'optimizely/exceptions'
 
 describe Optimizely::EventDispatcher do
+  let(:error_handler) { spy(Optimizely::NoOpErrorHandler.new) }
+  let(:spy_logger) { spy('logger') }
+
   before(:context) do
     @url = 'https://www.optimizely.com'
     @params = {
@@ -34,6 +36,9 @@
 
   before(:example) do
     @event_dispatcher = Optimizely::EventDispatcher.new
+    @customized_event_dispatcher = Optimizely::EventDispatcher.new(
+      logger: spy_logger, error_handler: error_handler
+    )
   end
 
   it 'should properly dispatch V2 (POST) events' do
@@ -64,7 +69,7 @@
     expect(a_request(:get, get_url)).to have_been_made.once
   end
 
-  it 'should properly dispatch V2 (GET) events' do
+  it 'should properly dispatch V2 (GET) events with timeout exception' do
     get_url = @url + '?a=111001&g=111028&n=test_event&u=test_user'
     stub_request(:get, get_url)
     event = Optimizely::Event.new(:get, get_url, @params, @post_headers)
@@ -74,4 +79,86 @@
 
     expect(result).to eq(timeout_error)
   end
+
+  it 'should log and handle Timeout error' do
+    get_url = @url + '?a=111001&g=111028&n=test_event&u=test_user'
+    stub_request(:post, get_url)
+    event = Optimizely::Event.new(:post, get_url, @params, @post_headers)
+    timeout_error = Timeout::Error.new
+    allow(HTTParty).to receive(:post).with(any_args).and_raise(timeout_error)
+    result = @customized_event_dispatcher.dispatch_event(event)
+
+    expect(result).to eq(timeout_error)
+    expect(spy_logger).to have_received(:log).with(
+      Logger::ERROR, 'Request Timed out. Error: Timeout::Error'
+    ).once
+
+    expect(error_handler).to have_received(:handle_error).once.with(Timeout::Error)
+  end
+
+  it 'should log and handle any standard error' do
+    get_url = @url + '?a=111001&g=111028&n=test_event&u=test_user'
+    stub_request(:post, get_url)
+    event = Optimizely::Event.new(:post, get_url, @params, @post_headers)
+    error = ArgumentError
+    allow(HTTParty).to receive(:post).with(any_args).and_raise(error)
+    result = @customized_event_dispatcher.dispatch_event(event)
+
+    expect(result).to eq(nil)
+    expect(spy_logger).to have_received(:log).with(
+      Logger::ERROR, 'Event failed to dispatch. Error: ArgumentError'
+    ).once
+
+    expect(error_handler).to have_received(:handle_error).once.with(ArgumentError)
+  end
+
+  it 'should log and handle any response with status code 4xx' do
+    stub_request(:post, @url).to_return(status: 499)
+    event = Optimizely::Event.new(:post, @url, @params, @post_headers)
+
+    @customized_event_dispatcher.dispatch_event(event)
+
+    expect(spy_logger).to have_received(:log).with(
+      Logger::ERROR, 'Event failed to dispatch with response code: 499'
+    ).once
+
+    error = Optimizely::HTTPCallError.new('HTTP Client Error: 499')
+    expect(error_handler).to have_received(:handle_error).once.with(error)
+  end
+
+  it 'should log and handle any response with status code 5xx' do
+    stub_request(:post, @url).to_return(status: 500)
+    event = Optimizely::Event.new(:post, @url, @params, @post_headers)
+
+    @customized_event_dispatcher.dispatch_event(event)
+
+    expect(spy_logger).to have_received(:log).with(
+      Logger::ERROR, 'Event failed to dispatch with response code: 500'
+    ).once
+
+    error = Optimizely::HTTPCallError.new('HTTP Server Error: 500')
+    expect(error_handler).to have_received(:handle_error).once.with(error)
+  end
+
+  it 'should do nothing on response with status code 3xx' do
+    stub_request(:post, @url).to_return(status: 399)
+    event = Optimizely::Event.new(:post, @url, @params, @post_headers)
+
+    response = @customized_event_dispatcher.dispatch_event(event)
+
+    expect(response).to be_nil
+    expect(spy_logger).not_to have_received(:log)
+    expect(error_handler).not_to have_received(:handle_error)
+  end
+
+  it 'should do nothing on response with status code 600' do
+    stub_request(:post, @url).to_return(status: 600)
+    event = Optimizely::Event.new(:post, @url, @params, @post_headers)
+
+    response = @customized_event_dispatcher.dispatch_event(event)
+
+    expect(response).to be_nil
+    expect(spy_logger).not_to have_received(:log)
+    expect(error_handler).not_to have_received(:handle_error)
+  end
 end