How to create a Docker container for Snakemake - python-3.x

Question

This is my first attempt at creating a Docker container.
I need to make a container for a legacy version of VarScan2 so I based much of it off a Dockerfile found for a newer version of VarScan2
I got an error trying to run the first container I built hinting that it may not be running because Snakemake.utils was not available. Therefore I think I need to install Snakemake in my container for which I need >= Python3.5.
I'm having trouble trying to get Python3.8 as Snakemake is failing to install on docker build:
Error:
Downloading snakemake-5.26.1.tar.gz (237 kB)
ERROR: Command errored out with exit status 1:
command: /usr/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-_50ix5/snakemake/setup.py'"'"'; __file__='"'"'/tmp/pip-install-_50ix5/snakemake/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-AMGZ1t
cwd: /tmp/pip-install-_50ix5/snakemake/
Complete output (2 lines):
At least Python 3.5 is required.
----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
Dockerfile
FROM ubuntu:14.04
MAINTAINER Matthew Jordan Oldach, moldach686#gmail.com
# create a working directory and work from there
RUN mkdir /tmp/install
WORKDIR /tmp/install
RUN apt-get update && apt-get install -y \
build-essential \
libncurses5-dev \
libgdbm-dev \
libnss3-dev \
libssl-dev \
libreadline-dev \
libffi-dev \
gcc \
make \
zlib1g-dev \
git \
wget \
python3-pip \
default-jre \
r-base \
bc
# [Download Python3.7.5 following these instructions][2]
RUN wget https://www.python.org/ftp/python/3.7.5/Python-3.7.5.tgz
RUN tar -xf Python-3.7.5.tgz
RUN cd python-3.7.5; ./configure --enable-optimizations; cd ..
# Download Snakemake
RUN wget https://bootstrap.pypa.io/get-pip.py
RUN python get-pip.py
RUN pip install snakemake
# Samtools 0.1.18 - note: 0.1.19 and 1.1 do NOT work, VarScan copynumber dies on the mpileup
RUN wget http://downloads.sourceforge.net/project/samtools/samtools/0.1.18/samtools-0.1.18.tar.bz2
RUN tar -xvf samtools-0.1.18.tar.bz2
# the make command generates a lot of warnings, none of them relevant to the final samtools code, hence 2>/dev/null
#RUN (cd samtools-0.1.18/ && make DFLAGS='-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -D_USE_KNETFILE -D_CURSES_LIB=0' LIBCURSES='' 2>/dev/null && mv samtools /usr/local/bin)
# get varscan
RUN wget -O /usr/local/bin/VarScan.jar https://netactuate.dl.sourceforge.net/project/varscan/VarScan.v2.3.9.jar
# Set WORKDIR to /data -- predefined mount location.
RUN mkdir /data
WORKDIR /data
# And clean up
RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/install
ENTRYPOINT ["bash", "java -jar /usr/local/bin/VarScan.jar"]
I'd appreciate if anyone could help me figure out what's going wrong here, thanks.
Update
The solution by OneCricketeer solved this solution.
Dockerfile Solution
FROM python:3.7.5
MAINTAINER Matthew Jordan Oldach, moldach686#gmail.com
# create a working directory and work from there
RUN mkdir /tmp/install
WORKDIR /tmp/install
RUN apt-get update && apt-get install -y \
gcc \
make \
zlib1g-dev \
git \
wget \
python3-pip \
default-jre \
r-base \
bc
# Download Snakemake
RUN wget https://bootstrap.pypa.io/get-pip.py
RUN python get-pip.py
RUN pip install snakemake
# Samtools 0.1.18 - note: 0.1.19 and 1.1 do NOT work, VarScan copynumber dies on the mpileup
RUN wget http://downloads.sourceforge.net/project/samtools/samtools/0.1.18/samtools-0.1.18.tar.bz2
RUN tar -xvf samtools-0.1.18.tar.bz2
# the make command generates a lot of warnings, none of them relevant to the final samtools code, hence 2>/dev/null
#RUN (cd samtools-0.1.18/ && make DFLAGS='-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -D_USE_KNETFILE -D_CURSES_LIB=0' LIBCURSES='' 2>/dev/null && mv samtools /usr/local/bin)
# get varscan
RUN wget -O /usr/local/bin/VarScan.jar https://netactuate.dl.sourceforge.net/project/varscan/VarScan.v2.3.9.jar
# Set WORKDIR to /data -- predefined mount location.
RUN mkdir /data
WORKDIR /data
# And clean up
RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/install
ENTRYPOINT ["bash", "java -jar /usr/local/bin/VarScan.jar"]