Add Ansible playbook env. setup wrapper script

The environment executing the test playbooks matters.  Establish a
script to bootstrap a known-good and fixed-version python virtual
environment.  Spell out precise execution requirements in a standard
pip 'requirements.txt' file, including version numbers and hashes.

Upon executing the ``venv-ansible-playbook.sh`` wrapper, a virtual
environment is setup and contained within a fixed (or temporary)
directory, with full logs from setup.  If this is to be preserved
across executions, the ``$WORKSPACE`` environment variable must be
set and exported beforehand.

Example execution command-line provided in script file

Signed-off-by: Chris Evich <cevich@redhat.com>

contrib/test/venv-ansible-playbook.sh

@@ -0,0 +1,97 @@
+#!/bin/bash
+
+# example usage
+#   $ ./venv-ansible-playbook.sh \
+#               -i 192.168.169.170 \
+#               --private-key=/path/to/key \
+#               --extra-vars "pullrequest=42" \
+#               --extra-vars "commit=abcd1234" \
+#               --user root \
+#               --verbose \
+#               $PWD/crio-integration-playbook.yaml
+
+SCRIPT_PATH=`realpath $(dirname $0)`
+REQUIREMENTS="$SCRIPT_PATH/requirements.txt"
+
+echo
+
+if ! type -P virtualenv &> /dev/null
+then
+    echo "Could not find required 'virtualenv' binary installed on system."
+    exit 1
+fi
+
+if [ "$#" -lt "1" ]
+then
+    echo "No ansible-playbook command-line options specified."
+    echo "usage: $0 -i whatever --private-key=something --extra-vars foo=bar playbook.yml"
+    exit 2
+fi
+
+# Avoid dirtying up repository, keep execution bits confined to a known location
+if [ -z "$WORKSPACE" ] || [ ! -d "$WORKSPACE" ]
+then
+    export WORKSPACE="$(mktemp -d)"
+    echo "Using temporary \$WORKSPACE=\"$WORKSPACE\" for execution environment."
+    echo "Directory will be removed upon exit.  Export this variable with path"
+    echo "to an existing directory to preserve contents."
+    trap 'rm -rf "$WORKSPACE"' EXIT
+else
+    echo "Using existing \$WORKSPACE=\"$WORKSPACE\" for execution environment."
+    echo "Directory will be left as-is upon exit."
+    # Don't recycle cache, next job may have different requirements
+    trap 'rm -rf "$PIPCACHE"' EXIT
+fi
+
+# All command failures from now on are fatal
+set -e
+echo
+echo "Bootstrapping trusted virtual environment, this may take a few minutes, depending on networking."
+echo "(logs:  \"$WORKSPACE/crio_venv_setup_log.txt\")"
+echo
+
+(
+    set -x
+    cd "$WORKSPACE"
+    # N/B: local system's virtualenv binary - uncontrolled version fixed below
+    virtualenv --no-site-packages --python=python2.7 ./.venvbootstrap
+    # Set up paths to install/operate out of $WORKSPACE/.venvbootstrap
+    source ./.venvbootstrap/bin/activate
+    # N/B: local system's pip binary - uncontrolled version fixed below
+    # pip may not support --cache-dir, force it's location into $WORKSPACE the ugly-way
+    OLD_HOME="$HOME"
+    export HOME="$WORKSPACE"
+    export PIPCACHE="$WORKSPACE/.cache/pip"
+    pip install --force-reinstall --upgrade pip==9.0.1
+    # Undo --cache-dir workaround
+    export HOME="$OLD_HOME"
+    # Install fixed, trusted, hashed versions of all requirements (including pip and virtualenv)
+    pip --cache-dir="$PIPCACHE" install --require-hashes \
+        --requirement "$SCRIPT_PATH/requirements.txt"
+
+    # Setup trusted virtualenv using hashed binary from requirements.txt
+    ./.venvbootstrap/bin/virtualenv --no-site-packages --python=python2.7 ./.cri-o_venv
+    # Exit untrusted virtualenv
+    deactivate
+
+    # Enter trusted virtualenv
+    source ./.cri-o_venv/bin/activate
+    # Re-install from cache
+    pip install --force-reinstall --upgrade pip==9.0.1
+    pip --cache-dir="$PIPCACHE" install --require-hashes \
+        --requirement "$SCRIPT_PATH/requirements.txt"
+    # Remove temporary bootstrap virtualenv
+    rm -rf ./.venvbootstrap
+    # Exit trusted virtualenv
+
+) &> $WORKSPACE/crio_venv_setup_log.txt;
+
+echo
+echo "Executing \"$WORKSPACE/.cri-o_venv/bin/ansible-playbook $@\""
+echo
+
+# Execute command-line arguments under virtualenv
+cd "$WORKSPACE"
+source ./.cri-o_venv/bin/activate
+./.cri-o_venv/bin/ansible-playbook $@
+deactivate