Hourly new connect of mqtt connection

[mtin]

Context

• OS and version used: Debian Buster running ROS melodic
• Python version: 3.7.3
• pip version: 19.3.1
• list of installed packages:

  Package               Version
  --------------------- ----------
  asn1crypto            0.24.0
  astroid               2.3.3
  awesome-slugify       1.6.5
  azure-iot-device      2.2.0
  Bottleneck            1.3.1
  catkin                0.7.20
  catkin-pkg-modules    0.4.15
  certifi               2020.12.5
  chardet               4.0.0
  coverage              4.5.2
  cryptography          2.6.1
  cycler                0.10.0
  Cython                0.29.14
  decorator             4.3.0
  defusedxml            0.6.0
  diskcache             4.1.0
  docutils              0.14
  empy                  3.3.2
  entrypoints           0.3
  fm-container          4.2.0
  fm-dataprocessing     5.2.0
  fm-eventhook          1.0.0
  fm-pipeline           4.0.5
  fm-resampler          3.0.1
  fm-spisource          5.0.0
  fm-streamconverter    9.1.0
  fm-streammanipulation 4.1.0
  fm-watchable          0.1.0
  gencpp                0.6.2
  geneus                2.2.6
  genlisp               0.4.16
  genmsg                0.5.12
  gennodejs             2.0.1
  genpy                 0.6.9
  idna                  2.10
  ijson                 3.1.3
  isort                 4.3.21
  janus                 0.4.0
  keyring               17.1.1
  keyrings.alt          3.1.1
  lazy-object-proxy     1.4.3
  mccabe                0.6.1
  message-filters       1.14.3
  mock                  2.0.0
  netifaces             0.10.9
  nose                  1.3.7
  numpy                 1.16.2
  olefile               0.46
  paho-mqtt             1.5.1
  pandas                1.0.0rc0
  pbr                   4.2.0
  Pillow                5.4.1
  pip                   19.3.1
  pyarrow               0.12.1
  pycrypto              2.6.1
  Pygments              2.3.1
  PyGObject             3.30.4
  pylint                2.4.4
  pyparsing             2.2.0
  PySocks               1.7.1
  python-dateutil       2.7.3
  python-gnupg          0.4.4
  pytz                  2018.9
  pyxdg                 0.25
  PyYAML                3.13
  regex                 2020.11.13
  requests              2.25.1
  requests-unixsocket   0.2.0
  roman                 2.0.0
  rosbag                1.14.3
  rosboost-cfg          1.14.7
  rosclean              1.14.7
  roscreate             1.14.7
  rosdistro-modules     0.8.0
  rosgraph              1.14.3
  roslaunch             1.14.3
  roslib                1.14.7
  roslz4                1.14.3
  rosmake               1.14.7
  rosmaster             1.14.3
  rosmsg                1.14.3
  rosnode               1.14.3
  rosparam              1.14.3
  rospkg-modules        1.2.3
  rospy                 1.14.3
  rosservice            1.14.3
  rostest               1.14.3
  rostopic              1.14.3
  rosunit               1.14.7
  roswtf                1.14.3
  RPi.GPIO              0.7.0
  scipy                 1.1.0
  SecretStorage         2.3.1
  setuptools            40.8.0
  six                   1.12.0
  topic-tools           1.14.3
  typed-ast             1.4.1
  ujson                 4.0.2
  Unidecode             0.4.21
  urllib3               1.25.11
  vcstools              0.1.42
  wheel                 0.32.3
  wrapt                 1.11.2
  wstool                0.1.17

Description of the issue

We are observing regular reconnects (approx. every hour) of the data connection. Listening on the event-grid topic for connected/disconnected events we can see this pattern (we noticed there are usually no disconnected events and there is no data loss)

Console log of the issue

> cat iotconnector-2.log | grep -v "Sending PUBLISH" | grep -v "Received PUBACK"
...
[paho][DEBUG] 2021-02-22 14:27:31,307: Sending SUBSCRIBE (d0, m1) [(b'$iothub/methods/POST/#', 1)]
[paho][DEBUG] 2021-02-22 14:27:31,450: Received SUBACK
[paho][DEBUG] 2021-02-22 15:25:29,435: Sending DISCONNECT
[paho][DEBUG] 2021-02-22 15:25:31,141: Sending CONNECT (u1, p1, wr0, wq0, wf0, c0, k60) client_id=b'b827eb526589'
[paho][DEBUG] 2021-02-22 15:25:31,171: Received CONNACK (1, 0)
[paho][DEBUG] 2021-02-22 16:23:29,440: Sending DISCONNECT
[paho][DEBUG] 2021-02-22 16:23:31,139: Sending CONNECT (u1, p1, wr0, wq0, wf0, c0, k60) client_id=b'b827eb526589'
[paho][DEBUG] 2021-02-22 16:23:31,171: Received CONNACK (1, 0)
[paho][DEBUG] 2021-02-22 17:21:29,446: Sending DISCONNECT
[paho][DEBUG] 2021-02-22 17:21:30,332: Sending CONNECT (u1, p1, wr0, wq0, wf0, c0, k60) client_id=b'b827eb526589'
[paho][DEBUG] 2021-02-22 17:21:30,363: Received CONNACK (1, 0)

No major blocker, but still - is this expected behaviour? Thanks in advance!

[cartertinney]

This is expected behavior. By default when using Shared Access Signature-based authentication (e.g. connection strings), we will disconnect and reconnect approximately every 58 minutes in order to renew the security credentials which will expire (by default) every hour. You should not experience any sort of data-loss during this automatic process.

If you would like to change the amount of time the credentials are valid for, use the optional sastoken_ttl kwarg when instantiating the client with your desired factory method. Pass through the number of seconds you would like your credentials to be valid for.

Is this sufficient to answer your concerns?

[mtin]

ok, cool, thank you for clearing that up!