cycarla-backend 0.1.0

Backend for Cycarla

cycarla-backend is a Python Flask server within a poetry project that runs within a Ubuntu 22.04 docker container.

Build Docker Image

From this directory,

docker build --platform linux/amd64 -t cycarla_backend .

• The platform argument exists because ubuntu:22.04 is a multi-architecture image but we want the x86_64 one specifically for compatibility with the carla wheel.

Run Docker Image

See run_backend.sh.

This server connects to a running CARLA simulation, so it requires the server's IP and port.

The CARLA simulation run_carla.sh and this cycarla backend run_backend.sh should be run on the same computer, communicating across localhost.

While it is possible to run the CARLA simulation and server on different computers, it will be very slow ( < 5 fps).

If you're using a different computer on your local network, use its local network IP. As an example:

export CARLA_SIM_IP=172.30.1.43
export CARLA_SIM_PORT=2000

The port is by default 2000 unless you set them otherwise.

For debugging, run the image without the entrypoint.sh script:

On Linux:

cd .. # go up to the root of this repository
docker run -e CARLA_SIM_IP -e CARLA_SIM_PORT --rm -it --platform linux/amd64 -p 9000:9000 --privileged -v /var/run/dbus:/var/run/dbus -v .:/workspaces/cycarla cycarla_backend

Inside the container:

cd /workspaces/cycarla/cycarla-backend
./entrypoint.sh

Windows (Native)

We run natively on Windows because WSL2 doesn't support Bluetooth.

Install Python 3.10

https://www.python.org/downloads/release/python-31011/

Scroll to the bottom and download the 'Windows Installer (64-bit)'.

Make sure to enable the bottom option "Add python.exe to PATH"

Install Poetry

Open Windows Powershell

First, install Scoop and pipx, then install Poetry.

pip install pipx
pipx install poetry

Navigate to this repository. For example, if you cloned this repo to your home directory:

cd ~
cd cycarla
cd cycarla-server

Then, use poetry to install and run the server:

poetry install
poetry shell
cd cycarla_server
python main.py

Allow firewall when prompted.

Uploading to Strava

This is a very rough demo of authenticating and uploading GPX files to Strava. It is not incorporated into cycarla at all at this point.

Reminder: The uploaded file should be owned by the user, not sudo. sudo chown username DEMO.gpx otherwise.

See gpx_demo.py for an equally rough, unincorporated proof of concept of creating GPX files.

Set up Strava API

Create an API Application.

Get client ID. In my case, 119241

Set up Cycarla (Client)

https://developers.strava.com/docs/authentication/

Requesting Access

https://developers.strava.com/docs/authentication/#detailsaboutrequestingaccess

Fill in client ID like so, and go to this address on a web browser.

https://www.strava.com/oauth/authorize?client_id=119241&response_type=code&redirect_uri=http://localhost/exchange_token&approval_prompt=force&scope=activity:write

This asks for write access for activities.

The resulting empty page has a URL that contains code=, such as: 7d2826e1e678870684bec2d405fbfadbd9f11487 (not valid code but should look similar)

In production, I think the callback URL should parse this and continue. For now we literally copy paste it from the URL.

Token Exchange

Use the code= string and other info from your API page to send:

curl -X POST https://www.strava.com/api/v3/oauth/token \
  -d client_id=ReplaceWithClientID \
  -d client_secret=ReplaceWithClientSecret \
  -d code=ReplaceWithCode \
  -d grant_type=authorization_code

Which provides you with access_token somewhere within the JSON.

Uploading GPX file

Finally, upload the .gpx file using access_token as the Bearer authorization.

curl -X POST https://www.strava.com/api/v3/uploads \                                                  
    -H "Authorization: Bearer fc5f6edef83b8fa0221ba31fd4e83a28045a1f9e" \
    -F activity_type="VirtualRide" \
    -F name="Test Walk" \
    -F description="Test description" \
    -F trainer=0 \
    -F commute=0 \
    -F data_type="gpx" \
    -F external_id="98765" \
    -F file=@outputfromdemo.gpx