Drop dances around virtualenv

* Drop dances around virtualenv installtion, install it via get-pip.py
* Allow to specify pip,wheel and setuptools versions as older openstack
  releases may not work with latest versions

Change-Id: I59a905dd08e1797135d805bee83a85c300746294

Dockerfile

@@ -44,6 +44,15 @@ ARG SPICE_REF=spice-html5-0.1.6
 
 # End Nova arguments
 
+# Virtualenv arguments
+
+ARG GET_PIP_URL="https://bootstrap.pypa.io/get-pip.py"
+ARG PIP_CONSTRAINT=""
+ARG SETUPTOOL_CONSTRAINT=""
+ARG WHEEL_CONSTRAIN=""
+
+# End virtualenv argumens
+
 ADD data /tmp/
 COPY scripts /opt/loci/scripts
 ADD bindep.txt pydep.txt $EXTRA_BINDEP $EXTRA_PYDEP /opt/loci/

scripts/install.sh

@@ -28,6 +28,7 @@ case ${distro} in
             lsb-release \
             patch \
             sudo \
+            wget \
             bind9-host \
             ${dpkg_python_packages[@]}
         apt-get install -y --no-install-recommends \

scripts/setup_pip.sh

@@ -2,41 +2,22 @@
 
 set -ex
 
+PIP_CONSTRAINT=${PIP_CONSTRAINT}
+SETUPTOOL_CONSTRAINT=${SETUPTOOL_CONSTRAINT}
+WHEEL_CONSTRAIN=${WHEEL_CONSTRAIN}
+VIRTUALENV="python3 -m virtualenv --python=python3 --no-seed"
 
-TMP_VIRTUALENV="python3 -m virtualenv --python=python3"
-
-# This little dance allows us to install the latest pip
-# without get_pip.py or the python-pip package (in epel on centos)
-if (( $(${TMP_VIRTUALENV} --version | grep -Po '[0-9]+\.[0-9]+\.[0-9]+' | cut -d. -f1) >= 14 )); then
-    SETUPTOOLS="--no-setuptools"
-fi
-if (( $(${TMP_VIRTUALENV} --version | grep -Po '[0-9]+\.[0-9]+\.[0-9]+' | cut -d. -f1) >= 20 )); then
-    SETUPTOOLS="--seed pip --download"
-fi
-
-# virtualenv 16.4.0 fixed symlink handling. The interaction of the new
-# corrected behavior with legacy bugs in packaged virtualenv releases in
-# distributions means we need to hold on to the pip bootstrap installation
-# chain to preserve symlinks. As distributions upgrade their default
-# installations we may not need this workaround in the future
-PIPBOOTSTRAP=/var/lib/pipbootstrap
-
-# Create the boostrap environment so we can get pip from virtualenv
-${TMP_VIRTUALENV} ${SETUPTOOLS} ${PIPBOOTSTRAP}
-source ${PIPBOOTSTRAP}/bin/activate
-
-# Install setuptools explicitly required for virtualenv > 20 installation
-pip install --upgrade setuptools
-
-# Upgrade to the latest version of virtualenv
-pip install --upgrade ${PIP_ARGS} virtualenv==20.7.2
-
-# Forget the cached locations of python binaries
-hash -r
+wget $GET_PIP_URL -O /tmp/get-pip.py
 
 # Create the virtualenv with the updated toolchain for openstack service
-virtualenv --seed pip --download /var/lib/openstack
+# for using python-rbd which is not pip installable and is only available
+# in packaged form.
+$VIRTUALENV  --system-site-packages --extra-search-dir=/tmp/wheels /var/lib/openstack
 
-# Deactivate the old bootstrap virtualenv and switch to the new one
-deactivate
 source /var/lib/openstack/bin/activate
+
+python /tmp/get-pip.py
+
+pip install --upgrade pip${PIP_CONSTRAINT}
+pip install --upgrade setuptools${SETUPTOOL_CONSTRAINT}
+pip install --upgrade wheel${WHEEL_CONSTRAIN}