[gentoo-portage-dev] [PATCH 1/2] FileCopier: capture exceptions

[Zac Medico]

Use ForkExecutor to capture exceptions instead of showing
a full traceback. FileCopier callers will now be responsible
for displaying relevant exception messages.

Bug: https://bugs.gentoo.org/699400
Signed-off-by: Zac Medico <zmedico@g.o>
---
 lib/portage/tests/util/test_file_copier.py | 44 ++++++++++++++++++++++
 lib/portage/util/_async/FileCopier.py      | 16 ++++----
 2 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100644 lib/portage/tests/util/test_file_copier.py

diff --git a/lib/portage/tests/util/test_file_copier.py b/lib/portage/tests/util/test_file_copier.py
new file mode 100644
index 000000000..01dfba494
--- /dev/null
+++ b/lib/portage/tests/util/test_file_copier.py
@@ -0,0 +1,44 @@
+# Copyright 2019 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+import errno
+import os
+import shutil
+import tempfile
+
+from portage.tests import TestCase
+from portage.util._async.FileCopier import FileCopier
+from portage.util._eventloop.global_event_loop import global_event_loop
+
+
+class FileCopierTestCase(TestCase):
+
+	def testFileCopier(self):
+		loop = global_event_loop()
+		tempdir = tempfile.mkdtemp()
+		try:
+
+			# regular successful copy
+			src_path = os.path.join(tempdir, 'src')
+			dest_path = os.path.join(tempdir, 'dest')
+			content = b'foo'
+			with open(src_path, 'wb') as f:
+				f.write(content)
+			copier = FileCopier(src_path=src_path, dest_path=dest_path, scheduler=loop)
+			copier.start()
+			loop.run_until_complete(copier.async_wait())
+			self.assertEqual(copier.returncode, 0)
+			copier.future.result()
+			with open(dest_path, 'rb') as f:
+				self.assertEqual(f.read(), content)
+
+			# failure due to nonexistent src_path
+			src_path = os.path.join(tempdir, 'does-not-exist')
+			copier = FileCopier(src_path=src_path, dest_path=dest_path, scheduler=loop)
+			copier.start()
+			loop.run_until_complete(copier.async_wait())
+			self.assertEqual(copier.returncode, 1)
+			self.assertEqual(copier.future.exception().errno, errno.ENOENT)
+			self.assertEqual(copier.future.exception().filename, src_path.encode('utf8'))
+		finally:
+			shutil.rmtree(tempdir)
diff --git a/lib/portage/util/_async/FileCopier.py b/lib/portage/util/_async/FileCopier.py
index 27e5ab4c0..3a0be4b63 100644
--- a/lib/portage/util/_async/FileCopier.py
+++ b/lib/portage/util/_async/FileCopier.py
@@ -1,17 +1,19 @@
-# Copyright 2013 Gentoo Foundation
+# Copyright 2013-2019 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
-from portage import os
 from portage import shutil
-from portage.util._async.ForkProcess import ForkProcess
+from portage.util.futures import asyncio
+from portage.util.futures.executor.fork import ForkExecutor
+from portage.util._async.AsyncTaskFuture import AsyncTaskFuture
 
-class FileCopier(ForkProcess):
+class FileCopier(AsyncTaskFuture):
 	"""
 	Asynchronously copy a file.
 	"""
 
 	__slots__ = ('src_path', 'dest_path')
 
-	def _run(self):
-		shutil.copy(self.src_path, self.dest_path)
-		return os.EX_OK
+	def _start(self):
+		self.future = asyncio.ensure_future(self.scheduler.run_in_executor(ForkExecutor(loop=self.scheduler),
+			shutil.copy, self.src_path, self.dest_path))
+		super(FileCopier, self)._start()
-- 
2.21.0