-set -eu -o pipefail
-
-virtualenv "$WORKSPACE/.virtualenvs/lftools"
-# shellcheck source=./.virtualenvs/lftools/bin/activate disable=SC1091
-source "$WORKSPACE/.virtualenvs/lftools/bin/activate"
-pip install --upgrade pip
-pip install --upgrade "lftools<1.0.0"
-pip freeze
+# DO NOT set -u as virtualenv's activate script has unbound variables
+set -e -o pipefail
+
+virtualenv --quiet "/tmp/v/lftools"
+# shellcheck source=/tmp/v/lftools/bin/activate disable=SC1091
+source "/tmp/v/lftools/bin/activate"
+pip install --quiet --upgrade "pip==9.0.3" setuptools
+
+case $LFTOOLS_MODE in
+ gerrit)
+ git clone https://gerrit.linuxfoundation.org/infra/releng/lftools.git /tmp/lftools
+ pushd /tmp/lftools
+ git fetch origin "$LFTOOLS_REFSPEC"
+ git checkout FETCH_HEAD
+ pip install --quiet --upgrade -r requirements.txt
+ pip install --quiet --upgrade -e .
+ popd
+ ;;
+
+ git)
+ pip install --quiet --upgrade git+https://gerrit.linuxfoundation.org/infra/releng/lftools.git@"$BRANCH"
+ ;;
+
+ release)
+ if [[ $LFTOOLS_VERSION =~ ^[0-9] ]]; then
+ LFTOOLS_VERSION="==$LFTOOLS_VERSION"
+ fi
+
+ pip install --quiet --upgrade "lftools${LFTOOLS_VERSION}"
+ ;;
+esac
+
+lftools --version
+
+# pipdeptree prints out a lot of information because lftools pulls in many
+# dependencies. Let's only print it if we want to debug.
+# echo "----> Pip Dependency Tree"
+# pip install --quiet --upgrade pipdeptree
+# pipdeptree