Dockerize prometheus-exporter

[gitbuda]

Example/proposal

FROM alpine:latest AS stg1
RUN apk add --update --no-cache binutils
RUN apk add --update --no-cache python3 git py3-pip  && \
#    ln -sf python3 /usr/bin/python && \
    pip3 install --no-cache setuptools pipreqs pyinstaller && \
    git clone -b main --single-branch --depth 1 https://github.com/memgraph/prometheus-exporter.git /opt/prometheus_exporter
WORKDIR "/opt/prometheus_exporter"
#   get required libraries using pipreqs
RUN pipreqs --force /opt/prometheus_exporter && \
    python3 -m pip install -r /opt/prometheus_exporter/requirements.txt
#  build executable self contained on opt
RUN pyinstaller --onefile main.py && ln -s ./dist/main ./main

# finally, create the actual container to be run, with only the required files for the exporter and stored in opt
FROM alpine:latest AS stg3
EXPOSE 9115/tcp
ENV PYTHONUNBUFFERED=1
WORKDIR "/opt/prometheus_exporter"
COPY --from=stg1 /opt/prometheus_exporter/main /opt/prometheus_exporter/main
#  use echo to write out the config file
ENV MGDBSERVER=memgraph
RUN echo $'exporter:\n  port: 9115\nmemgraph:\n  endpoint_url: [http://127.0.0.1\n](http://127.0.0.1/n)  port: 9091\ngeneral:\n  pull_frequency_seconds: 5' > config.yaml  && \
    sed -i 's/[127.0.0.1/](http://127.0.0.1/)'"${MGDBSERVER}"'/g' /opt/prometheus_exporter/config.yaml