Make networking/http test more resilient (bugfix)

providers/base/bin/networking_http.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+#
+# This file is part of Checkbox.
+#
+# Copyright 2024 Canonical Ltd.
+# Written by:
+# Pierre Equoy <pierre.equoy@canonical.com>
+#
+# Checkbox is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3,
+# as published by the Free Software Foundation.
+#
+# Checkbox is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Checkbox. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import argparse
+import random
+import subprocess
+import sys
+import time
+
+
+def http_connect(
+ url, max_attempts: int = 5, initial_delay=1, backoff_factor=2, max_delay=60
+):
+ """
+ Use `wget` to try to connect to `url`. If attempt fails, the next one is
+ made after adding a random delay calculated using a backoff and a jitter
+ (with a maximum delay of 60 seconds).
+ """
+ for attempt in range(1, max_attempts + 1):
+ print(
+ "Trying to connect to {} (attempt {}/{})".format(
+ url, attempt, max_attempts
+ )
+ )
+ try:
+ subprocess.run(
+ [
+ "wget",
+ "-SO",
+ "/dev/null",
+ url,
+ ],
+ check=True,
+ )
+ return
+ except subprocess.CalledProcessError as exc:
+ print("Attempt {} failed: {}".format(attempt, exc))
+ print()
+ delay = min(initial_delay * (backoff_factor**attempt), max_delay)
+ jitter = random.uniform(
+ 0, delay * 0.5
+ ) # Jitter: up to 50% of the delay
+ final_delay = delay + jitter
+ print(
+ "Waiting for {:.2f} seconds before retrying...".format(
+ final_delay
+ )
+ )
+ time.sleep(final_delay)
+ raise SystemExit("Failed to connect to {}!".format(url))
+
+
+def main(args):
+ parser = argparse.ArgumentParser()
+ parser.add_argument("url", help="URL to try to connect to")
+ parser.add_argument(
+ "--attempts",
+ default="5",
+ help="Number of connection attempts (default %(default)s)",
+ )
+ args = parser.parse_args(args)
+ http_connect(args.url, int(args.attempts))
+
+
+if __name__ == "__main__":
+ sys.exit(main(sys.argv[1:]))

providers/base/tests/test_networking_http.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+#
+# This file is part of Checkbox.
+#
+# Copyright 2024 Canonical Ltd.
+# Written by:
+# Pierre Equoy <pierre.equoy@canonical.com>
+#
+# Checkbox is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3,
+# as published by the Free Software Foundation.
+#
+# Checkbox is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Checkbox. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import subprocess
+from unittest import TestCase
+from unittest.mock import patch
+
+import networking_http
+
+
+class NetworkingHTTPTests(TestCase):
+ @patch("networking_http.subprocess.run")
+ @patch("networking_http.time.sleep")
+ def test_http_connect_max_retries(self, mock_sleep, mock_run):
+ with self.assertRaises(SystemExit):
+ networking_http.http_connect("test", 0)
+
+ @patch("networking_http.subprocess.run")
+ @patch("networking_http.time.sleep")
+ def test_http_connect_success(self, mock_sleep, mock_run):
+ """
+ Test that `http_connect` returns safely if the wget command returns 0
+ """
+ self.assertEqual(networking_http.http_connect("test", 3), None)
+
+ @patch("networking_http.subprocess.run")
+ @patch("networking_http.time.sleep")
+ def test_http_connect_failure(self, mock_sleep, mock_run):
+ """
+ Test that if set to 3 retries, the connection command (wget, run
+ through subprocess.run) will be called 3 times
+ """
+ mock_run.side_effect = subprocess.CalledProcessError(1, "")
+ with self.assertRaises(SystemExit):
+ networking_http.http_connect("test", 3)
+ self.assertEqual(mock_run.call_count, 3)
+
+ @patch("networking_http.http_connect")
+ def test_main(self, mock_http_connect):
+ args = ["test", "--attempts", "6"]
+ networking_http.main(args)
+ mock_http_connect.assert_called_with("test", 6)

providers/base/units/networking/jobs.pxu

@@ -59,7 +59,8 @@ user: root
 plugin: shell
 category_id: com.canonical.plainbox::networking
 id: networking/http
-command: wget -SO /dev/null http://"$TRANSFER_SERVER"
+environ: TRANSFER_SERVER
+command: networking_http.py http://"$TRANSFER_SERVER"
 _description:
  Automated test case to make sure that it's possible to download files through HTTP
 
@@ -99,4 +100,4 @@ requires:
  model_assertion.gadget != "pi"
  {%- else %}
  lsb.release >= '18'
- {% endif -%}
+ {% endif -%}