Ubuntu 16.04: Switch from Python 2.7 to Python 3.10

Because in Funq we (finally) dropped support for Python 2. Manually
installing a recent Python version because Python 3.5 from the
official Ubuntu repos might lead to troubles sooner or later since it
is EOL already.

In addition, no longer installing Python packages we actually don't
need in this image anymore.

Author: ubruhin

ubuntu-16.04/Dockerfile

@@ -16,14 +16,14 @@ RUN apt-get update -q && apt-get -y -q install --no-install-recommends \
     graphviz \
     libc++-dev \
     libc++abi-dev \
+    libffi-dev \
     libglu1-mesa-dev \
     libqt5opengl5 \
     libqt5opengl5-dev \
     libqt5svg5-dev \
     libqt5sql5-sqlite \
     make \
     openssl \
-    python \
     qt5-default \
     qtdeclarative5-dev \
     qtdeclarative5-qtquick2-plugin \
@@ -35,14 +35,43 @@ RUN apt-get update -q && apt-get -y -q install --no-install-recommends \
     zlib1g-dev \
   && rm -rf /var/lib/apt/lists/*
 
-# Install PIP (the version from APT is not sufficient)
-RUN curl "https://bootstrap.pypa.io/2.7/get-pip.py" -o get-pip.py \
-  && python get-pip.py
+# Remove DST root certificate since it is not compatible with OpenSSL 1.0. This
+# is only needed for building the Docker image, afterwards we will have a newer
+# OpenSSL library.
+# See https://medium.com/geekculture/will-you-be-impacted-by-letsencrypt-dst-root-ca-x3-expiration-d54a018df257
+RUN sed -i 's/mozilla\/DST_Root_CA_X3.crt/!mozilla\/DST_Root_CA_X3.crt/g' \
+  /etc/ca-certificates.conf && update-ca-certificates
 
-# Install Python packages
-RUN pip install \
-  "future==0.17.1" \
-  "flake8==3.7.7"
+# Install OpenSSL 1.1 for Python/pip.
+ARG OPENSSL_VERSION="1.1.1l"
+RUN wget -c "https://www.openssl.org/source/openssl-$OPENSSL_VERSION.tar.gz" -O /tmp.tar.gz \
+  && tar -zxf /tmp.tar.gz \
+  && cd "./openssl-$OPENSSL_VERSION" \
+  && ./config --prefix=/usr --openssldir=/etc/ssl '-Wl,--enable-new-dtags,-rpath,$(LIBRPATH)' \
+  && make -s -j8 \
+  && make install > /dev/null \
+  && cd .. \
+  && rm -rf "./openssl-$OPENSSL_VERSION" \
+  && rm /tmp.tar.gz
+
+# Install Python & pip
+# Note: Actually Python 3.5 from the official Ubuntu repositories is
+# sufficient for us, but having a more recent version simplifies dependency
+# management since then we can drop support for Python 3.5.
+ARG PYTHON_VERSION="3.10.0"
+RUN wget "https://www.python.org/ftp/python/$PYTHON_VERSION/Python-$PYTHON_VERSION.tgz" \
+  && tar xzvf "./Python-$PYTHON_VERSION.tgz" \
+  && cd "./Python-$PYTHON_VERSION" \
+  && ./configure \
+  && make -j8 \
+  && make install \
+  && cd .. \
+  && rm -rf "./Python-$PYTHON_VERSION" \
+  && rm "./Python-$PYTHON_VERSION.tgz" \
+  && update-alternatives --install /usr/bin/python python /usr/local/bin/python3.10 100 \
+  && curl "https://bootstrap.pypa.io/pip/get-pip.py" -o get-pip.py \
+  && python get-pip.py \
+  && rm get-pip.py
 
 # LibrePCB's unittests expect that there is a USERNAME environment variable
 ENV USERNAME="root"