Handle python binary look for scripts

We have some scripts that we deploy via tripleo that use inline python.
For this we need to be able to find an available python on the system in
order for it to work. This change adds a lookup function to the scripts
to find a working version of python as /usr/bin/python may not exist.

Change-Id: Ida7a7cbd064ebdb923f38c9102eb4b0771f9b273
Related-Blueprint: python3-support

deployed-server/scripts/enable-ssh-admin.sh

@@ -14,8 +14,13 @@ SSH_HOSTKEY_OPTIONS="-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
 SHORT_TERM_KEY_COMMENT="TripleO split stack short term key"
 SLEEP_TIME=5
 
+# needed to handle where python lives
+function get_python() {
+  command -v python3 || command -v python2 || command -v python || exit 1
+}
+
 function overcloud_ssh_hosts_json {
-    echo "$OVERCLOUD_HOSTS" | python -c '
+    echo "$OVERCLOUD_HOSTS" | $(get_python) -c '
 from __future__ import print_function
 import json, re, sys
 print(json.dumps(re.split("\s+", sys.stdin.read().strip())))'
@@ -24,7 +29,7 @@ print(json.dumps(re.split("\s+", sys.stdin.read().strip())))'
 function overcloud_ssh_key_json {
     # we pass the contents to Mistral instead of just path, otherwise
     # the key file would have to be readable for the mistral user
-    cat "$1" | python -c 'import json,sys; print(json.dumps(sys.stdin.read()))'
+    cat "$1" | $(get_python) -c 'import json,sys; print(json.dumps(sys.stdin.read()))'
 }
 
 function workflow_finished {

firstboot/os-net-config-mappings.yaml

@@ -61,10 +61,15 @@ resources:
             eth_addr=$(cat /sys/class/net/*/address | tr '\n' ',')
             mkdir -p /etc/os-net-config
 
+            # needed to handle where python lives
+            function get_python() {
+              command -v python3 || command -v python2 || command -v python || exit 1
+            }
+
             # Create an os-net-config mapping file, note this defaults to
             # /etc/os-net-config/mapping.yaml, so we use that name despite
             # rendering the result as json
-            echo '$node_lookup' | python -c "
+            echo '$node_lookup' | $(get_python) -c "
             import json
             import sys
             import copy

puppet/extraconfig/pre_deploy/per_node.yaml

@@ -31,10 +31,14 @@ resources:
         #!/bin/sh
         node_id=$(dmidecode --s system-uuid | awk 'match($0, /[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{12}/) { print substr($0, RSTART, RLENGTH) }')
 
+        # needed to handle where python lives
+        function get_python() {
+          command -v python3 || command -v python2 || command -v python || exit 1
+        }
         # Create a /etc/puppet/hieradata/UUID.json file to provide
         # the data of the NodeDataLookup parameter that matches the
         # system UUID
-        echo $node_lookup | python -c "
+        echo $node_lookup | $(get_python) -c "
         import json
         import sys
         input = sys.stdin.readline() or '{}'

validation-scripts/all-nodes.sh

@@ -1,6 +1,11 @@
 #!/bin/bash
 set -e
 
+# needed to handle where python lives
+function get_python() {
+  command -v python3 || command -v python2 || command -v python || exit 1
+}
+
 function ping_retry() {
   local IP_ADDR=$1
   local TIMES=${2:-'10'}
@@ -33,7 +38,7 @@ function ping_controller_ips() {
       networks=$(ip r | grep -v default | cut -d " " -f 1)
     fi
     for LOCAL_NETWORK in $networks; do
-      in_network=$(python -c "import ipaddress; net=ipaddress.ip_network(u'$LOCAL_NETWORK'); addr=ipaddress.ip_address(u'$REMOTE_IP'); print(addr in net)")
+      in_network=$($(get_python) -c "import ipaddress; net=ipaddress.ip_network(u'$LOCAL_NETWORK'); addr=ipaddress.ip_address(u'$REMOTE_IP'); print(addr in net)")
       if [[ $in_network == "True" ]]; then
         echo "Trying to ping $REMOTE_IP for local network ${LOCAL_NETWORK}."
         set +e