try this

Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu
 WORKDIR /opt/strudel2/src
 COPY . /opt/strudel2/src
 RUN apt update && apt install -y python3 gcc python3-pip openssh-client
-RUN pip3 install -r requirements.txt && python3 ./setup.py install
+RUN pip3 install -r requirements.txt &&  pip install .
 RUN mkdir -p /var/www/.ssh && chown www-data:www-data /var/www/.ssh && chmod 700 /var/www/.ssh
 EXPOSE 8080 8090
 CMD ["./runscript"]

requirements.txt

@@ -14,7 +14,6 @@ pip==21.3.1
 pytz==2021.3
 requests==2.27.1
 requests-oauthlib==1.3.0
-setuptools==60.5.0
 six==1.16.0
 SQLAlchemy==1.4.30
 urllib3==1.26.8