Support editable installation in all cases

An editable installation allows changes to be made to the source code
directly, and have those changes applied immediately without having to
reinstall.

    pip install -e /path/to/kolla-ansible

Above is currently working only in virtualenv, but there is no reason to
not allow in all cases. This is usefull for example when user is
building his own docker container with editable kolla-ansible installed
from git without virtualenv.

Change-Id: I185f7c09c3f026fd6926a26001393f066ff1860d
(cherry picked from commit 22a6765)

Author: keuko

tools/kolla-ansible

@@ -22,6 +22,7 @@ function check_environment_coherence {
     local ansible_python_cmdline
     # NOTE(yoctozepto): may have multiple parts
     ansible_python_cmdline=${ansible_shebang_line#\#\!}
+    ansible_python_version=$($ansible_python_cmdline -c 'import sys; print(str(sys.version_info[0])+"."+str(sys.version_info[1]))')
 
     if ! $ansible_python_cmdline --version &>/dev/null; then
         echo "ERROR: Ansible Python is not functional." >&2
@@ -66,21 +67,38 @@ function check_environment_coherence {
 
 function find_base_dir {
     local dir_name
+    local python_dir
     dir_name=$(dirname "$0")
     # NOTE(yoctozepto): Fix the case where dir_name is a symlink and VIRTUAL_ENV might not be. This
     # happens with pyenv-virtualenv, see https://bugs.launchpad.net/kolla-ansible/+bug/1903887
     dir_name=$(readlink -e "$dir_name")
+    python_dir="python${ansible_python_version}"
     if [ -z "$SNAP" ]; then
         if [[ ${dir_name} == "/usr/bin" ]]; then
-            BASEDIR=/usr/share/kolla-ansible
+            if test -f /usr/lib/${python_dir}/*-packages/kolla-ansible.egg-link; then
+                # Editable install.
+                BASEDIR="$(head -n1 /usr/lib/${python_dir}/*-packages/kolla-ansible.egg-link)"
+            else
+                BASEDIR=/usr/share/kolla-ansible
+            fi
         elif [[ ${dir_name} == "/usr/local/bin" ]]; then
-            BASEDIR=/usr/local/share/kolla-ansible
+            if test -f /usr/local/lib/${python_dir}/*-packages/kolla-ansible.egg-link; then
+                # Editable install.
+                BASEDIR="$(head -n1 /usr/local/lib/${python_dir}/*-packages/kolla-ansible.egg-link)"
+            else
+                BASEDIR=/usr/local/share/kolla-ansible
+            fi
         elif [[ ${dir_name} == ~/.local/bin ]]; then
-            BASEDIR=~/.local/share/kolla-ansible
+            if test -f ~/.local/lib/${python_dir}/*-packages/kolla-ansible.egg-link; then
+                # Editable install.
+                BASEDIR="$(head -n1 ~/.local/lib/${python_dir}/*-packages/kolla-ansible.egg-link)"
+            else
+                BASEDIR=~/.local/share/kolla-ansible
+            fi
         elif [[ -n ${VIRTUAL_ENV} ]] && [[ ${dir_name} == "$(readlink -e "${VIRTUAL_ENV}/bin")" ]]; then
-            if test -f ${VIRTUAL_ENV}/lib/python*/site-packages/kolla-ansible.egg-link; then
+            if test -f ${VIRTUAL_ENV}/lib/${python_dir}/site-packages/kolla-ansible.egg-link; then
                 # Editable install.
-                BASEDIR="$(head -n1 ${VIRTUAL_ENV}/lib/python*/site-packages/kolla-ansible.egg-link)"
+                BASEDIR="$(head -n1 ${VIRTUAL_ENV}/lib/${python_dir}/*-packages/kolla-ansible.egg-link)"
             else
                 BASEDIR="${VIRTUAL_ENV}/share/kolla-ansible"
             fi