Add integration tests for st2common.util.green.shell.run_command()

function, including regression test case for zombie / stray process
issue.

Author: Kami

st2common/tests/integration/test_util_green.py

@@ -0,0 +1,106 @@
+# Copyright 2020 The StackStorm Authors.
+# Copyright 2019 Extreme Networks, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+from st2common.util.monkey_patch import monkey_patch
+
+monkey_patch()
+
+from st2tests.base import IntegrationTestCase
+
+from st2common.util.green.shell import run_command
+from st2common.util.green.shell import TIMEOUT_EXIT_CODE
+from st2common.util.shell import kill_process
+from st2common.util.shell import quote_unix
+
+_all__ = ["GreenShellUtilsTestCase"]
+
+
+class GreenShellUtilsTestCase(IntegrationTestCase):
+    def test_run_command_success(self):
+        # 0 exit code
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd='echo "test stdout" ; >&2 echo "test stderr"', shell=True
+        )
+        self.assertEqual(exit_code, 0)
+        self.assertEqual(stdout.strip(), b"test stdout")
+        self.assertEqual(stderr.strip(), b"test stderr")
+        self.assertFalse(timed_out)
+
+        # non-zero exit code
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd='echo "test stdout" ; >&2 echo "test stderr" ; exit 5', shell=True
+        )
+        self.assertEqual(exit_code, 5)
+        self.assertEqual(stdout.strip(), b"test stdout")
+        self.assertEqual(stderr.strip(), b"test stderr")
+        self.assertFalse(timed_out)
+
+        # implicit non zero code (invalid command)
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd="foobarbarbazrbar", shell=True
+        )
+        self.assertEqual(exit_code, 127)
+        self.assertEqual(stdout.strip(), b"")
+        self.assertTrue(b"foobarbarbazrbar: not found" in stderr.strip())
+        self.assertFalse(timed_out)
+
+    def test_run_command_timeout_shell_and_custom_kill_func(self):
+        # This test represents our local runner setup where we use a preexec_func + custom kill_func
+        # NOTE: When using shell=True. we should alaways use custom kill_func to ensure child shell
+        # processses are in fact killed as well.
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd='echo "pre sleep";  sleep 1589; echo "post sleep"',
+            preexec_func=os.setsid,
+            timeout=1,
+            kill_func=kill_process,
+            shell=True,
+        )
+        self.assertEqual(exit_code, TIMEOUT_EXIT_CODE)
+        self.assertEqual(stdout.strip(), b"pre sleep")
+        self.assertEqual(stderr.strip(), b"")
+        self.assertTrue(timed_out)
+
+        # Verify there is no zombie process left laying around
+        self.assertNoStrayProcessesLeft("sleep 1589")
+
+    def test_run_command_timeout_no_shell_no_custom_kill_func(self):
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd=["sleep", "1599"], preexec_func=os.setsid, timeout=1
+        )
+        self.assertEqual(exit_code, TIMEOUT_EXIT_CODE)
+        self.assertEqual(stdout.strip(), b"")
+        self.assertEqual(stderr.strip(), b"")
+        self.assertTrue(timed_out)
+
+        # Verify there is no zombie process left laying around
+        self.assertNoStrayProcessesLeft("sleep 1599")
+
+    def assertNoStrayProcessesLeft(self, grep_string: str) -> None:
+        """
+        Assert that there are no stray / zombie processes left with the provided command line
+        string.
+        """
+        exit_code, stdout, stderr, timed_out = run_command(
+            cmd="ps aux | grep %s | grep -v grep" % (quote_unix(grep_string)),
+            shell=True,
+        )
+
+        if stdout.strip() != b"" and stderr.strip() != b"":
+            raise AssertionError(
+                "Expected no stray processes, but found Some. stdout: %s, stderr: %s"
+                % (stdout, stderr)
+            )