Merge pull request #89 from briandunn/fix/cld-aint-all-bad

Fix: don't assume SIGCLD is bad. Check child statuses.

Author: briandunn

lib/flatware/rspec/formatters/console.rb

@@ -34,7 +34,7 @@ def summarize(checkpoints)
         end
 
         def summarize_remaining(remaining)
-          progress_formatter.output.puts(colorizer.wrap(<<~MESSAGE, :detail))
+          out.puts(colorizer.wrap(<<~MESSAGE, :detail))
 
             The following specs weren't run:
 

lib/flatware/sink.rb

@@ -25,18 +25,19 @@ def initialize(jobs:, formatter:, sink:, worker_count: 0, **)
         @checkpoints = []
         @completed_jobs = []
         @formatter = formatter
+        @interrupted = false
         @jobs = group_jobs(jobs, worker_count).freeze
         @queue = @jobs.dup
         @sink = sink
         @workers = Set.new(worker_count.times.to_a)
       end
 
       def start
-        @signal = Signal.listen(&method(:summarize_remaining))
+        Signal.listen(formatter, &method(:on_interrupt))
         formatter.jobs jobs
         DRb.start_service(sink, self, verbose: Flatware.verbose?)
         DRb.thread.join
-        !failures?
+        !(failures? || interrupted?)
       end
 
       def ready(worker)
@@ -73,8 +74,13 @@ def respond_to_missing?(name, include_all)
 
       private
 
+      def on_interrupt
+        @interrupted = true
+        summarize_remaining
+      end
+
       def interrupted?
-        @signal&.interrupted?
+        @interrupted
       end
 
       def check_finished!

lib/flatware/sink/signal.rb

@@ -1,46 +1,77 @@
 module Flatware
   module Sink
     class Signal
-      def initialize(&on_interrupt)
+      Message = Struct.new(:message)
+
+      attr_reader :formatter
+
+      def initialize(formatter, &on_interrupt)
+        @formatter = formatter
         Thread.main[:signals] = Queue.new
 
         @on_interrupt = on_interrupt
       end
 
-      def interrupted?
-        !signals.empty?
-      end
-
       def listen
         Thread.new(&method(:handle_signals))
 
         ::Signal.trap('INT') { signals << :int }
-        ::Signal.trap('CLD') { signals << :cld }
+        ::Signal.trap('CLD') do
+          signals << :cld if child_failed?
+        end
 
         self
       end
 
-      def self.listen(&block)
-        new(&block).listen
+      def self.listen(formatter, &block)
+        new(formatter, &block).listen
       end
 
       private
 
+      def child_status
+        _worker_pid, status = begin
+          Process.wait2(-1, Process::WNOHANG)
+        rescue Errno::ECHILD
+          []
+        end
+        status
+      end
+
+      def child_statuses
+        statuses = []
+        loop do
+          status = child_status
+          return statuses unless status
+
+          statuses << status
+        end
+      end
+
+      def child_failed?
+        child_statuses.any? { |status| !status.success? }
+      end
+
       def handle_signals
-        puts signal_message(signals.pop)
-        Process.waitall
-        @on_interrupt.call
-        puts 'done.'
+        signal_message(signals.pop) do
+          Process.waitall
+          @on_interrupt.call
+        end
+
         abort
       end
 
       def signal_message(signal)
-        format(<<~MESSAGE, { cld: 'A worker died', int: 'Interrupted' }.fetch(signal))
+        formatter.message(Message.new(format(<<~MESSAGE, { cld: 'A worker died', int: 'Interrupted' }.fetch(signal))))
 
           %s!
 
-          Cleaning up. Please wait...
+          Waiting for workers to finish their current jobs...
         MESSAGE
+
+        yield
+
+        formatter.message(Message.new('done.'))
       end
 
       def signals

spec/flatware/sink/signal_spec.rb

@@ -0,0 +1,105 @@
+require 'spec_helper'
+
+describe Flatware::Sink::Signal do
+  let(:formatter_queue) { Queue.new }
+
+  let(:formatter) do
+    queue = formatter_queue
+
+    Class.new do
+      define_method(:message, &queue.method(:push))
+    end.new
+  end
+
+  let(:signal_blocks) { {} }
+
+  let(:on_interrupt) do
+    -> {}.tap do |block|
+      allow(block).to receive(:call)
+    end
+  end
+
+  before do
+    allow(Process).to receive(:waitall)
+
+    allow(Signal).to receive(:trap) do |signal, &block|
+      signal_blocks[signal] = block
+    end
+
+    @subject = described_class.listen(formatter, &on_interrupt).tap do |instance|
+      allow(instance).to receive(:abort)
+    end
+  end
+
+  attr_reader :subject
+
+  def send_signal(signal)
+    signal_blocks.fetch(signal).call
+  end
+
+  shared_examples_for 'a signal initiated shutdown' do |expected_message|
+    before do
+      @messages = 2.times.map do
+        Timeout.timeout(1, StandardError, 'formatter did not receive within 1 sec') do
+          formatter_queue.pop.message
+        end
+      end
+    end
+
+    attr_reader :messages
+
+    it 'aborts' do
+      expect(subject).to have_received(:abort)
+    end
+
+    it 'tells the formatter to emit the signal message' do
+      expect(messages).to match([include(expected_message), 'done.'])
+    end
+
+    it 'calls on_interrupt' do
+      expect(on_interrupt).to have_received(:call)
+    end
+
+    it 'waits for workers' do
+      expect(Process).to have_received(:waitall)
+    end
+  end
+
+  describe 'on SIGINT' do
+    before do
+      send_signal('INT')
+    end
+
+    it_should_behave_like 'a signal initiated shutdown', 'Interrupted'
+  end
+
+  describe 'on SIGCLD' do
+    context 'when a child failed' do
+      before do
+        allow(Process).to receive(:wait2).and_return(
+          [nil, double(success?: true)],
+          [nil, double(success?: false)],
+          nil
+        )
+
+        send_signal('CLD')
+      end
+
+      it_should_behave_like 'a signal initiated shutdown', 'A worker died'
+    end
+
+    context 'when a child has not failed' do
+      before do
+        allow(Process).to receive(:wait2).and_return nil
+
+        send_signal('CLD')
+      end
+
+      it 'does nothing' do
+        expect(on_interrupt).to_not have_received(:call)
+        expect(subject).to_not have_received(:abort)
+        expect(formatter_queue).to be_empty
+      end
+    end
+  end
+end

spec/flatware/sink_spec.rb

@@ -31,57 +31,6 @@
     }
   end
 
-  def connect
-    Timeout.timeout(2) do
-      sleep 0.1
-      DRbObject.new_with_uri(sink_endpoint)
-    rescue DRb::DRbConnError
-      retry
-    end
-  end
-
-  def fork_server(&block)
-    IO.popen('-') do |f|
-      if f
-        connect.ready(1)
-        block.call(f)
-        Process.waitall
-      else
-        described_class.start_server(**defaults, jobs: [job])
-      end
-    end
-  end
-
-  context 'when I have work to do' do
-    let(:job) { Flatware::Job.new('int.feature') }
-
-    context 'but a worker dies' do
-      it 'explains and exits non-zero' do
-        fork_server do |server|
-          Process.kill 'CLD', server.pid
-
-          expect(server.read).to match(/A worker died/).and(match(/int\.feature/))
-
-          Process.wait(server.pid)
-          expect(Process.last_status).to_not be_success
-        end
-      end
-    end
-
-    context 'but am interupted' do
-      it 'explains and exits non-zero' do
-        fork_server do |server|
-          Process.kill 'INT', server.pid
-
-          expect(server.read).to match(/Interrupted/).and(match(/int\.feature/))
-
-          Process.wait(server.pid)
-          expect(Process.last_status).to_not be_success
-        end
-      end
-    end
-  end
-
   context 'there is no work' do
     it 'sumarizes' do
       server = described_class::Server.new jobs: [], **defaults