python/iqm: allow connecting via TCP, TLS, websockets

[ymorin-orange]

Changes

• applications:
  • interqueuemanager:
    • restore connection throuch TCP
    • add support for TLS connections
    • add support for websockets connections

Close #475

Test

How to test

Note: in the following:

• lines starting with $ are to be executed on your machine, as a non-root user;
• lines starting with (docker)$ are to be executed in the Docker container;
• lines starting with (docker)🐍 $ are to be executed in the Docker container, in the python venv.

1. Prepare a test environment:
   1. be sure to have unrestricted access to test.mosquitto.org (IPv4 and IPv6)
   2. run an MQTT client that listens on test.mosquitto.org:

      $ mosquitto_sub \
          -h test.mosquitto.org -p 8886 \
          --tls-version tlsv1.3 --capath /etc/ssl/certs/ \
          -i SUyX8BNsbCr633okVYVwVPIX \
          -t 'default/+/v2x/#' \
          -V 5 \
          -F %J

   3. in another terminal, start a container with Python 3.11 and the necessary packages:

      $ docker container run \
          --detach \
          --name iot3 \
          --rm \
          -ti \
          --network host \
          -e http_proxy \
          -e https_proxy \
          -e no_proxy \
          --user $(id -u):$(id -u) \
          --mount type=bind,source=$(pwd),destination=$(pwd) \
          --workdir $(pwd) \
          python:3.11.14-slim-trixie \
          /bin/bash -il
      
      $ docker container exec -u 0:0 iot3 apt update
      $ docker container exec -u 0:0 iot3 apt install -y git build-essential socat
      $ docker container exec -d iot3 socat UNIX-LISTEN:/tmp/mqtt.socket,fork TCP4:test.mosquitto.org:1884
      
      $ docker container attach iot3

      Note: the socat command exposes the MQTT broker from test.mosquitto.org, inside the container, listening on the UNIX socket /tmp/mqtt.socket.
   4. prepare a Python 3.11 environment, with tests dependencies
      and packages' dependencies:

      (docker)$ python3.11 -m venv /tmp/venv
      (docker)$ . /tmp/venv/bin/activate
      (docker)🐍 $ pip --disable-pip-version-check --no-cache-dir install \
                      -r python/requirements-tests.txt \
                      $(sed -r -e '/.*"(.+(==|>=|<=).+)".*/!d; s//\1/; s/ //g;' \
                        python/*/pyproject.toml
                       )

      Note: we install the packages dependencies manually, and do not rely on pip to do so, because our Python packages depend one on the others by git hash, as they are not published on PyPi yet, so installing one of our packages may overwrite another.
2. create the IQM configuration files:
   • /tmp/iqm-unix.cfg

     (docker)🐍 $ cat >/tmp/iqm-unix.cfg <<_EOF_
     [general]
     instance-id = geo_4afad84c
     prefix = default
     suffix = v2x
     [local]
     socket-path = /tmp/mqtt.socket
     username = rw
     password = readwrite
     _EOF_
     

   • /tmp/iqm-tcp.cfg

     (docker)🐍 $ cat >/tmp/iqm-tcp.cfg <<_EOF_
     [general]
     instance-id = geo_4afad84c
     prefix = default
     suffix = v2x
     [local]
     host = test.mosquitto.org
     port = 1884
     tls = false
     username = rw
     password = readwrite
     _EOF_
     

   • /tmp/iqm-tls.cfg

     (docker)🐍 $ cat >/tmp/iqm-tls.cfg <<_EOF_
     [general]
     instance-id = geo_4afad84c
     prefix = default
     suffix = v2x
     [local]
     host = test.mosquitto.org
     port = 8886
     _EOF_
     

   • /tmp/iqm-wss.cfg

     (docker)🐍 $ cat >/tmp/iqm-wss.cfg <<_EOF_
     [general]
     instance-id = geo_4afad84c
     prefix = default
     suffix = v2x
     [local]
     host = test.mosquitto.org
     port = 8081
     websocket_path = /
     _EOF_
     

3. Build the Python packages:

   (docker)🐍 $ for pkg in python/*/; do
                   python -m build -w "${pkg}" || break
                done

4. Install the Python packages:

   (docker)🐍 $ pip --disable-pip-version-check --no-cache-dir \
                       install --no-deps python/*/dist/*.whl

5. Test the IQM on various connection protocols::
   1. run the IQM with one of the configuration files above, e.g. with /tmp/iqm-unix.cfg:

      (docker)🐍 $ its-iqm -c /tmp/iqm-unix.cfg

   2. send an MQTT message:

      $ mosquitto_pub \
          -h test.mosquitto.org -p 8886 \
          --tls-version tlsv1.3 --capath /etc/ssl/certs/ \
          -i H15/VGZbiFtxzPVrCrolUXbL \
          -t 'default/inQueue/v2x/cam/0/1/2/3/3/2/1/0' \
          -V 5 \
          -m '["test-me"]'

   3. stop the IQM (with Ctrl-C) and start again at step 2, above, using another configuration file

Expected results

1. The test environment is ready
2. The configuration files were all created successfully
3. The packages were all built successfully
4. The packages were all installed successfully
5. The IQM relays messages as expected, whatever the connection means: messages posted on inQueue are copied to outQueue and interQueue