distro: allow distro to specify a default locale

Currently the cloud-init default locale (en_US.UTF-8) is set by
the base datasource class.  This patch allows a distro to overide
the fallback value with one that's available in the distro but continues
to respect an image which has preconfigured a locale.

- Distro object now has a get_locale method which will return a
  preconfigure locale setting by checking the distros locale system
  configuration file.  If not set or not present, return the default
  locale of en_US.UTF-8 which retains behavior of all previous cloud-init
  releases.
- Apply locale now handles regenerating locales or system configuration
  files as needed.
- Adjust apply_locale logic to skip locale-regen if the specified LANG
  value is C.UTF-8,C, or POSIX; they do not require regeneration.
- Further add unittests to exercise the default paths for Ubuntu and
  non-ubuntu paths to validate they get the LANG expected.

1 files changed, 8 insertions, 1 deletions

diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py
index 952caf35..9a43fbee 100644
--- a/cloudinit/sources/__init__.py
+++ b/cloudinit/sources/__init__.py
@@ -44,6 +44,7 @@ class DataSourceNotFoundException(Exception):
 class DataSource(object):
 
     dsmode = DSMODE_NETWORK
+    default_locale = 'en_US.UTF-8'
 
     def __init__(self, sys_cfg, distro, paths, ud_proc=None):
         self.sys_cfg = sys_cfg
@@ -150,7 +151,13 @@ class DataSource(object):
         return None
 
     def get_locale(self):
-        return 'en_US.UTF-8'
+        """Default locale is en_US.UTF-8, but allow distros to override"""
+        locale = self.default_locale
+        try:
+            locale = self.distro.get_locale()
+        except NotImplementedError:
+            pass
+        return locale
 
     @property
     def availability_zone(self):