Wrap up multiprocessing work

flake8/checker.py

@@ -65,6 +65,18 @@ class Manager(object):
             self.process_queue = multiprocessing.Queue()
             self.results_queue = multiprocessing.Queue()
 
+    @staticmethod
+    def _cleanup_queue(q):
+        while not q.empty():
+            q.get_nowait()
+
+    def _force_cleanup(self):
+        if self.using_multiprocessing:
+            for proc in self.processes:
+                proc.join(0.2)
+            self._cleanup_queue(self.process_queue)
+            self._cleanup_queue(self.results_queue)
+
     def _job_count(self):
         # type: () -> Union[int, NoneType]
         # First we walk through all of our error cases:
@@ -116,10 +128,29 @@ class Manager(object):
         # it to an integer
         return int(jobs)
 
+    def _results(self):
+        seen_done = 0
+        while True:
+            LOG.info('Retrieving results')
+            result = self.results_queue.get()
+            if result == 'DONE':
+                seen_done += 1
+                if seen_done >= self.jobs:
+                    break
+                continue
+
+            yield result
+
     def _report_after_parallel(self):
         style_guide = self.style_guide
-        for (filename, results) in iter(self.results_queue.get, 'DONE'):
-            results = sorted(results, key=lambda tup: (tup[2], tup[3]))
+        final_results = {}
+        for (filename, results) in self._results():
+            final_results[filename] = results
+
+        for checker in self.checkers:
+            filename = checker.filename
+            results = sorted(final_results[filename],
+                             key=lambda tup: (tup[1], tup[2]))
             for (error_code, line_number, column, text) in results:
                 style_guide.handle_error(
                     code=error_code,
@@ -148,6 +179,7 @@ class Manager(object):
         for checker in iter(self.process_queue.get, 'DONE'):
             LOG.debug('Running checker for file "%s"', checker.filename)
             checker.run_checks(self.results_queue)
+        self.results_queue.put('DONE')
 
     def is_path_excluded(self, path):
         # type: (str) -> bool
@@ -195,9 +227,7 @@ class Manager(object):
         This iterates over each of the checkers and reports the errors sorted
         by line number.
         """
-        if self.using_multiprocessing:
-            self._report_after_parallel()
-        else:
+        if not self.using_multiprocessing:
             self._report_after_serial()
 
     def run(self):
@@ -215,9 +245,13 @@ class Manager(object):
                 proc.daemon = True
                 proc.start()
                 self.processes.append(proc)
+            proc = multiprocessing.Process(target=self._report_after_parallel)
+            proc.start()
+            LOG.info('Started process to report errors')
+            self.processes.append(proc)
         else:
             for checker in self.checkers:
-                checker.run_checks()
+                checker.run_checks(self.results_queue)
 
     def start(self):
         """Start checking files."""
@@ -235,11 +269,8 @@ class Manager(object):
         for i in range(self.jobs):
             self.process_queue.put('DONE')
 
-        LOG.info('Joining process workers')
-        for process in self.processes:
-            process.join()
-        LOG.info('Processes joined')
-        self.results_queue.put('DONE')
+        for proc in self.processes:
+            proc.join()
 
 
 class FileChecker(object):
@@ -371,7 +402,7 @@ class FileChecker(object):
                         exc.error_message)
 
         if results_queue is not None:
-            results_queue.put_nowait((self.filename, self.results))
+            results_queue.put((self.filename, self.results))
 
     def handle_comment(self, token, token_text):
         """Handle the logic when encountering a comment token."""

flake8/main/cli.py

@@ -264,11 +264,13 @@ class Application(object):
         """Run the actual checks with the FileChecker Manager."""
         self.file_checker_manager.start()
         self.file_checker_manager.run()
+        LOG.info('Finished running')
         self.file_checker_manager.stop()
 
     def report_errors(self):
         # type: () -> NoneType
         """Report all the errors found by flake8 3.0."""
+        LOG.info('Reporting errors')
         self.file_checker_manager.report()
 
     def _run(self, argv):