FROM python:3.8 as builder1

# Use a virtual environment.
RUN python -m venv /app/venv
ENV PATH="/app/venv/bin:$PATH"

# Upgrade pip.
RUN python -m pip install --upgrade pip

# Make a directory for the service files and copy the service repo into the container.
WORKDIR /app/service
COPY ./requirements.txt ./requirements.txt

# Install dependencies.
RUN python3 -m pip install -r requirements.txt

# Make a new container and copy all relevant files over to filter out temporary files
# produced during setup to reduce the final container's size.
FROM python:3.8

WORKDIR /app/
COPY --from=builder1  /app .
ENV PATH="/app/venv/bin:$PATH"

WORKDIR /app/service