From 51ecf0a869720ae5e8845b95fd2973b2760dcecf Mon Sep 17 00:00:00 2001
From: Davanum Srinivas <davanum@gmail.com>
Date: Thu, 5 Jan 2017 16:11:17 -0500
Subject: [PATCH] Introduce a PYTHON env var

* $PYTHON will have the path to python runtime to be used
* Use $PYTHON to run all the scripts

Change-Id: Ib5ab7820fc18cae5e50ea47302b610494197ad47
---
 functions-common         |  6 +++---
 lib/horizon              | 12 ++----------
 tools/install_prereqs.sh |  3 +++
 3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/functions-common b/functions-common
index 8d03b88d24..8d32bb4148 100644
--- a/functions-common
+++ b/functions-common
@@ -87,7 +87,7 @@ function write_clouds_yaml {
         CA_CERT_ARG="--os-cacert $SSL_BUNDLE_FILE"
     fi
     # demo -> devstack
-    $TOP_DIR/tools/update_clouds_yaml.py \
+    $PYTHON $TOP_DIR/tools/update_clouds_yaml.py \
         --file $CLOUDS_YAML \
         --os-cloud devstack \
         --os-region-name $REGION_NAME \
@@ -99,7 +99,7 @@ function write_clouds_yaml {
         --os-project-name demo
 
     # alt_demo -> devstack-alt
-    $TOP_DIR/tools/update_clouds_yaml.py \
+    $PYTHON $TOP_DIR/tools/update_clouds_yaml.py \
         --file $CLOUDS_YAML \
         --os-cloud devstack-alt \
         --os-region-name $REGION_NAME \
@@ -111,7 +111,7 @@ function write_clouds_yaml {
         --os-project-name alt_demo
 
     # admin -> devstack-admin
-    $TOP_DIR/tools/update_clouds_yaml.py \
+    $PYTHON $TOP_DIR/tools/update_clouds_yaml.py \
         --file $CLOUDS_YAML \
         --os-cloud devstack-admin \
         --os-region-name $REGION_NAME \
diff --git a/lib/horizon b/lib/horizon
index 4cabbe483c..9c7ec005a2 100644
--- a/lib/horizon
+++ b/lib/horizon
@@ -81,11 +81,7 @@ function configure_horizon {
     # Horizon is installed as develop mode, so we can compile here.
     # Message catalog compilation is handled by Django admin script,
     # so compiling them after the installation avoids Django installation twice.
-    if python3_enabled; then
-        (cd $HORIZON_DIR; python${PYTHON3_VERSION} manage.py compilemessages)
-    else
-        (cd $HORIZON_DIR; python manage.py compilemessages)
-    fi
+    (cd $HORIZON_DIR; $PYTHON manage.py compilemessages)
 
     # ``local_settings.py`` is used to override horizon default settings.
     local local_settings=$HORIZON_DIR/openstack_dashboard/local/local_settings.py
@@ -166,11 +162,7 @@ function install_django_openstack_auth {
         git_clone_by_name "django_openstack_auth"
         # Compile message catalogs before installation
         _prepare_message_catalog_compilation
-        if python3_enabled; then
-            (cd $dir; python${PYTHON3_VERSION} setup.py compile_catalog)
-        else
-            (cd $dir; python setup.py compile_catalog)
-        fi
+        (cd $dir; $PYTHON setup.py compile_catalog)
         setup_dev_lib "django_openstack_auth"
     fi
     # if we aren't using this library from git, then we just let it
diff --git a/tools/install_prereqs.sh b/tools/install_prereqs.sh
index 8895e1e77c..da59093581 100755
--- a/tools/install_prereqs.sh
+++ b/tools/install_prereqs.sh
@@ -83,6 +83,9 @@ fi
 
 if python3_enabled; then
     install_python3
+    export PYTHON=$(which python${PYTHON3_VERSION} 2>/dev/null || which python3 2>/dev/null)
+else
+    export PYTHON=$(which python 2>/dev/null)
 fi
 
 # Mark end of run