sanity-meta-openstack.bbclass: add class for bbappend files checking

Add a new class sanity-meta-openstack.bbclass,
to check whether necessary settings are available
for bbappend files and preferred version setting
in this layer to be effective and warn users if not.

In addition, a variable SKIP_SANITY_META_OPENSTACK_CHECK
is added to enable users to explicitly skip the
checking to avoid unwanted warnings.

Signed-off-by: Mingli Yu <Mingli.Yu@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/meta-openstack/README b/meta-openstack/README
index 81b843b..8506250 100644
--- a/meta-openstack/README
+++ b/meta-openstack/README
@@ -5,6 +5,25 @@ This layer provides support for building the packages from the OpenStack project
 The layer contains recipes for the nova, glance, keystone, cinder, quantum, swift
 and horizon components.
 
+The bbappend files for some recipes (e.g. postgresql) and preferred version setting
+(e.g. python-networkx)in this layer need to have 'openstack' in DISTRO_FEATURES to
+have effect. To enable them, add in configuration file the following line.
+
+  DISTRO_FEATURES_append = " openstack"
+
+If meta-openstack is included, but openstack is not enabled as a
+distro feature a warning is printed at parse time:
+
+    You have included the meta-openstack layer, but
+    'openstack' has not been enabled in your DISTRO_FEATURES. Some bbappend files
+    and preferred version setting may not take effect. See the meta-openstack README
+    for details on enabling openstack support.
+
+If you know what you are doing, this warning can be disabled by setting the following
+variable in your configuration:
+
+  SKIP_META_OPENSTACK_SANITY_CHECK = 1
+
 Dependencies
 ------------