Dockerfile

# Ubuntu version: 20.04, 18.04
ARG VARIANT=20.04
FROM ubuntu:${VARIANT}

# Install needed packages. Use a separate RUN statement to add your own dependencies.
RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
    && apt-get autoremove -y && apt-get clean -y && rm -rf /var/lib/apt/lists/*

# Base 
RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
    && apt-get -y install --no-install-recommends build-essential git

# Python 3
RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
    && apt-get -y install --no-install-recommends python3 python3-pip

RUN pip3 install --upgrade pip

RUN apt install python3-dev -y

RUN cd "$(dirname $(which python3))" \
    && ln -s idle3 idle \
    && ln -s pydoc3 pydoc \
    && ln -s python3 python \ 
    && ln -s python3-config python-config

COPY requirements.txt requirements.txt
RUN python3 -m pip install -r requirements.txt 

ENV TZ=Europe/Madrid
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

# Install OpenJDK-8
RUN apt-get update && \
    apt-get install -y openjdk-8-jdk && \
    apt-get install -y ant && \
    apt-get clean;
    
# Fix certificate issues
RUN apt-get update && \
    apt-get install ca-certificates-java && \
    apt-get clean && \
    update-ca-certificates -f;

# Setup JAVA_HOME -- useful for docker commandline
ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64/
RUN export JAVA_HOME