From d4d2183c486128677f71cfdb9164886cb2014fed Mon Sep 17 00:00:00 2001
From: Lucas Alvares Gomes <lucasagomes@gmail.com>
Date: Wed, 21 Sep 2016 14:49:51 -0300
Subject: [PATCH] DevStack: Use Jinja2 for templating when creating new VMs

This patch is changing the configure-vm.py script to use Jinja2
templating when creating new VMs instead of string interpolation.

Jinja templating allows more complex templating such as conditionals
which will greatly simplify the code for creating Legacy BIOS or UEFI
supported VMs.

Change-Id: Id4a8432923fa71ca8f3f28edd1235d3a318c3e95
Partial-Bug: #1625616
---
 devstack/tools/ironic/scripts/configure-vm.py |  9 ++++---
 devstack/tools/ironic/templates/vm.xml        | 24 +++++++++----------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/devstack/tools/ironic/scripts/configure-vm.py b/devstack/tools/ironic/scripts/configure-vm.py
index cc466629de..5a235b6dd1 100755
--- a/devstack/tools/ironic/scripts/configure-vm.py
+++ b/devstack/tools/ironic/scripts/configure-vm.py
@@ -16,6 +16,7 @@
 import argparse
 import os.path
 
+import jinja2
 import libvirt
 
 templatedir = os.path.join(os.path.dirname(os.path.dirname(__file__)),
@@ -80,8 +81,10 @@ def main():
     parser.add_argument('--disk-format', default='qcow2',
                         help='Disk format to use.')
     args = parser.parse_args()
-    with open(templatedir + '/vm.xml', 'rb') as f:
-        source_template = f.read()
+
+    env = jinja2.Environment(loader=jinja2.FileSystemLoader(templatedir))
+    template = env.get_template('vm.xml')
+
     params = {
         'name': args.name,
         'imagefile': args.image,
@@ -108,7 +111,7 @@ def main():
         params['console'] = CONSOLE_LOG % {'console_log': args.console_log}
     else:
         params['console'] = CONSOLE_PTY
-    libvirt_template = source_template % params
+    libvirt_template = template.render(**params)
     conn = libvirt.open("qemu:///system")
 
     a = conn.defineXML(libvirt_template)
diff --git a/devstack/tools/ironic/templates/vm.xml b/devstack/tools/ironic/templates/vm.xml
index 64d7899ba4..78297fdd04 100644
--- a/devstack/tools/ironic/templates/vm.xml
+++ b/devstack/tools/ironic/templates/vm.xml
@@ -1,10 +1,10 @@
-<domain type='%(engine)s'>
-  <name>%(name)s</name>
-  <memory unit='KiB'>%(memory)s</memory>
-  <vcpu>%(cpus)s</vcpu>
+<domain type='{{ engine }}'>
+  <name>{{ name }}</name>
+  <memory unit='KiB'>{{ memory }}</memory>
+  <vcpu>{{ cpus }}</vcpu>
   <os>
-    <type arch='%(arch)s' machine='pc-1.0'>hvm</type>
-    <boot dev='%(bootdev)s'/>
+    <type arch='{{ arch }}' machine='pc-1.0'>hvm</type>
+    <boot dev='{{ bootdev }}'/>
     <bootmenu enable='no'/>
     <bios useserial='yes'/>
   </os>
@@ -18,10 +18,10 @@
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
-    <emulator>%(emulator)s</emulator>
+    <emulator>{{ emulator }}</emulator>
     <disk type='file' device='disk'>
-      <driver name='qemu' type='%(disk_format)s' cache='writeback'/>
-      <source file='%(imagefile)s'/>
+      <driver name='qemu' type='{{ disk_format }}' cache='writeback'/>
+      <source file='{{ imagefile }}'/>
       <target dev='vda' bus='virtio'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
     </disk>
@@ -29,8 +29,8 @@
       <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
     </controller>
     <interface type='bridge'>
-      <source bridge='%(bridge)s'/>
-      <model type='%(nicdriver)s'/>
+      <source bridge='{{ bridge }}'/>
+      <model type='{{ nicdriver }}'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
     </interface>
     <input type='mouse' bus='ps2'/>
@@ -39,7 +39,7 @@
       <model type='cirrus' vram='9216' heads='1'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
     </video>
-    %(console)s
+    {{ console }}
     <memballoon model='virtio'>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
     </memballoon>