Implement the Client loop

Gemfile.lock

@@ -35,6 +35,8 @@ GEM
     docile (1.1.5)
     domain_name (0.5.25)
       unf (>= 0.0.5, < 1.0.0)
+    factory_girl (4.5.0)
+      activesupport (>= 3.0.0)
     faraday (0.9.2)
       multipart-post (>= 1.2, < 3)
     faraday_middleware (0.10.0)
@@ -92,6 +94,7 @@ DEPENDENCIES
   codeclimate-test-reporter
   coursemology-evaluator!
   coveralls
+  factory_girl
   rake
   rspec
   simplecov

coursemology-evaluator.gemspec

@@ -21,6 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rspec'
+  spec.add_development_dependency 'factory_girl'
   spec.add_development_dependency 'simplecov'
   spec.add_development_dependency 'coveralls'
   spec.add_development_dependency 'codeclimate-test-reporter'

lib/coursemology/evaluator/cli.rb

@@ -1,7 +1,7 @@
 require 'optparse'
 
 class Coursemology::Evaluator::CLI
-  Options = Struct.new(:host, :api_token, :api_user_email)
+  Options = Struct.new(:host, :api_token, :api_user_email, :one_shot)
 
   def self.start(argv)
     new.start(argv)
@@ -15,7 +15,7 @@ def run(argv)
     options = optparse!(argv)
     Coursemology::Evaluator::Client.initialize(options.host, options.api_user_email,
                                                options.api_token)
-    Coursemology::Evaluator::Client.new.run
+    Coursemology::Evaluator::Client.new(options.one_shot).run
   end
 
   private
@@ -39,6 +39,10 @@ def optparse!(argv) # rubocop:disable Metrics/MethodLength
       parser.on('-uUSER', '--api-user-email=USER') do |user|
         options.api_user_email = user
       end
+
+      parser.on('-o', '--one-shot') do
+        options.one_shot = true
+      end
     end
 
     option_parser.parse!(argv)

lib/coursemology/evaluator/client.rb

@@ -7,9 +7,50 @@ def self.initialize(host, api_user_email, api_token)
     Coursemology::Evaluator::Models::Base.initialize
   end
 
-  def initialize
+  # @param [Boolean] one_shot If the client should only fire one request.
+  def initialize(one_shot = false)
+    @terminate = one_shot
   end
 
   def run
+    Signal.trap('SIGTERM', method(:on_sig_term))
+
+    loop do
+      allocate_evaluations
+      break if @terminate
+
+      sleep(1.minute)
+    end
+  end
+
+  private
+
+  # Requests evaluations from the server.
+  def allocate_evaluations
+    evaluations = Coursemology::Evaluator::Models::ProgrammingEvaluation.allocate
+    on_allocate(evaluations)
+  end
+
+  # The callback for handling an array of allocated evaluations.
+  #
+  # @param [Array<Coursemology::Evaluator::Models::ProgrammingEvaluation>] evaluations The
+  #   evaluations retrieved from the server.
+  def on_allocate(evaluations)
+    evaluations.each do |evaluation|
+      on_evaluation(evaluation)
+    end
+  end
+
+  # The callback for handling an evaluation.
+  #
+  # @param [Coursemology::Evaluator::Models::ProgrammingEvaluation] evaluation The evaluation
+  #   retrieved from the server.
+  def on_evaluation(evaluation)
+    evaluation.save
+  end
+
+  # The callback for handling SIGTERM sent to the process.
+  def on_sig_term
+    @terminate = true
   end
 end

spec/coursemology/evaluator/cli_spec.rb

@@ -1,9 +1,11 @@
 RSpec.describe Coursemology::Evaluator::CLI do
   let(:host) { 'http://localhost:3000' }
+  let!(:original_api_token) { Coursemology::Evaluator::Models::Base.api_token }
   let(:api_token) { 'abcd' }
   let(:api_user_email) { 'test@example.org' }
   let(:argv) do
-    ["--host=#{host}", "--api-token=#{api_token}", "--api-user-email=#{api_user_email}"]
+    ["--host=#{host}", "--api-token=#{api_token}", "--api-user-email=#{api_user_email}",
+     '--one-shot']
   end
 
   describe Coursemology::Evaluator::CLI::Options do
@@ -22,22 +24,27 @@
     describe '#start' do
       subject { Coursemology::Evaluator::CLI.new }
       it 'calls #run' do
-        expect(subject).to receive(:run).and_call_original
+        expect(subject).to receive(:run)
         subject.start(argv)
       end
     end
 
     describe '#run' do
+      let(:api_token) { original_api_token }
       subject { Coursemology::Evaluator::CLI.new.run(argv) }
 
       it 'creates a client' do
         expect(Coursemology::Evaluator::Client).to receive(:new).and_call_original
-        subject
+        VCR.use_cassette('client/no_pending_evaluations') do
+          subject
+        end
       end
 
       it 'runs the client' do
         expect(Coursemology::Evaluator::Client).to receive_message_chain(:new, :run)
-        subject
+        VCR.use_cassette('client/no_pending_evaluations') do
+          subject
+        end
       end
     end
   end

spec/coursemology/evaluator/client_spec.rb

@@ -15,4 +15,42 @@
       end
     end
   end
+
+  describe '#run' do
+    it 'loops until @terminate is set' do
+      expect(subject).to receive(:allocate_evaluations).at_least(:once)
+      allow(subject).to receive(:sleep) do
+        sleep(0.1.seconds)
+      end
+
+      Thread.new { subject.instance_variable_set(:@terminate, true) }
+      subject.run
+    end
+  end
+
+  describe '#allocate_evaluations' do
+    context 'when an evaluation is provided' do
+      let(:dummy_evaluation) { build(:programming_evaluation) }
+      before do
+        expect(Coursemology::Evaluator::Models::ProgrammingEvaluation).to \
+          receive(:allocate).and_return([dummy_evaluation])
+      end
+
+      it 'calls #on_allocate with the evaluation' do
+        expect(subject).to receive(:on_allocate).with([dummy_evaluation]).and_call_original
+        subject.send(:allocate_evaluations)
+      end
+    end
+  end
+
+  describe '#on_sig_term' do
+    it 'terminates the loop' do
+      expect(subject).to receive(:allocate_evaluations).at_least(:once)
+      allow(subject).to receive(:sleep) do
+        sleep(0.1.seconds)
+      end
+      Thread.new { subject.send(:on_sig_term) }
+      subject.run
+    end
+  end
 end

spec/factories/programming_evaluations.rb

@@ -0,0 +1,8 @@
+FactoryGirl.define do
+  factory :programming_evaluation, class: Coursemology::Evaluator::Models::ProgrammingEvaluation do
+    id 1
+    language 'Polyglot::Language::Python::Python2Point7'
+    memory_limit 32
+    time_limit 5
+  end
+end

spec/support/factory_girl.rb

@@ -0,0 +1,9 @@
+require 'factory_girl'
+
+RSpec.configure do |config|
+  config.include FactoryGirl::Syntax::Methods
+
+  config.before(:suite) do
+    FactoryGirl.find_definitions
+  end
+end