Pinned package version, multistage-build, fix train bug

Dockerfile

@@ -1,23 +1,22 @@
-FROM sjawhar/muselsl
-
+FROM sjawhar/pipenv:3.7-2020.6.2 as packages
 USER root
+WORKDIR /scratch
 COPY app/Pipfile app/Pipfile.lock ./
-RUN DEV_PACKAGES=" \
-        python3-pip \
-    " \
- && apt-get update \
- && apt-get install -y --no-install-recommends \
-        python3-opengl=3.1.0+dfsg-2 \
- && apt-get install -y $DEV_PACKAGES \
- && pip3 install pipenv \
- && pipenv install --system \
- && pip3 uninstall -y pipenv \
- && apt-get purge -y --auto-remove $DEV_PACKAGES \
- && rm -rf /var/lib/apt/lists/* \
- && rm -rf /root/.cache
+RUN PIP_TARGET=/scratch/packages PIP_IGNORE_INSTALLED=1 pipenv install --system
 
+FROM sjawhar/muselsl
+USER root
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends \
+        freeglut3=2.8.1-3 \
+        libglu1-mesa=9.0.0-2.1+b3 \
+ && rm -rf /var/lib/apt/lists/*
 RUN usermod -a -G audio muselsl
 
+ARG PACKAGES_DIR=/opt/site-packages
+COPY --from=packages /scratch/packages $PACKAGES_DIR
+ENV PYTHONPATH=$PYTHONPATH:$PACKAGES_DIR
+
 ARG NO_WANDER_DIR=/opt/no_wander
 COPY app/src $NO_WANDER_DIR
 ENV PYTHONPATH=$PYTHONPATH:$NO_WANDER_DIR/..