Docker graceful shutdown for honcho and flask

Dockerfile

FROM python:latest

RUN mkdir -p /app
WORKDIR /app

RUN python -m venv venv
ENV VIRTUAL_ENV /venv
ENV PATH /venv/bin:$PATH

ADD requirements.txt /app/requirements.txt

# Add prod requirements
ADD requirements /app/requirements

RUN pip install -r /app/requirements.txt
# Fix for requests and urllib
RUN pip install --upgrade requests
RUN pip install honcho

ADD . /app/

# Required in elastic beanstalk
EXPOSE 5000

# Do it w/ quotation marks to forward kill signals properly
CMD ["honcho", "start", "-e", "/app/vars/env.deploy", "-f", "/app/Procfile"]

Procfile

scheduler: flask db upgrade && flask rq scheduler -v
worker_a: flask rq worker -v
worker_b: flask rq worker -v
worker_c: flask rq worker -v