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.

2 files changed, 58 insertions, 24 deletions

diff --git a/tests/unittests/test_distros/test_debian.py b/tests/unittests/test_distros/test_debian.py
index 2330ad52..72d3aad6 100644
--- a/tests/unittests/test_distros/test_debian.py
+++ b/tests/unittests/test_distros/test_debian.py
@@ -1,67 +1,85 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
-from ..helpers import (CiTestCase, mock)
-
-from cloudinit.distros.debian import apply_locale
+from cloudinit import distros
 from cloudinit import util
+from ..helpers import (FilesystemMockingTestCase, mock)
 
 
 @mock.patch("cloudinit.distros.debian.util.subp")
-class TestDebianApplyLocale(CiTestCase):
+class TestDebianApplyLocale(FilesystemMockingTestCase):
+
+    def setUp(self):
+        super(TestDebianApplyLocale, self).setUp()
+        self.new_root = self.tmp_dir()
+        self.patchOS(self.new_root)
+        self.patchUtils(self.new_root)
+        self.spath = self.tmp_path('etc/default/locale', self.new_root)
+        cls = distros.fetch("debian")
+        self.distro = cls("debian", {}, None)
+
     def test_no_rerun(self, m_subp):
         """If system has defined locale, no re-run is expected."""
-        spath = self.tmp_path("default-locale")
         m_subp.return_value = (None, None)
         locale = 'en_US.UTF-8'
-        util.write_file(spath, 'LANG=%s\n' % locale, omode="w")
-        apply_locale(locale, sys_path=spath)
+        util.write_file(self.spath, 'LANG=%s\n' % locale, omode="w")
+        self.distro.apply_locale(locale, out_fn=self.spath)
         m_subp.assert_not_called()
 
+    def test_no_regen_on_c_utf8(self, m_subp):
+        """If locale is set to C.UTF8, do not attempt to call locale-gen"""
+        m_subp.return_value = (None, None)
+        locale = 'C.UTF-8'
+        util.write_file(self.spath, 'LANG=%s\n' % 'en_US.UTF-8', omode="w")
+        self.distro.apply_locale(locale, out_fn=self.spath)
+        self.assertEqual(
+            [['update-locale', '--locale-file=' + self.spath,
+              'LANG=%s' % locale]],
+            [p[0][0] for p in m_subp.call_args_list])
+
     def test_rerun_if_different(self, m_subp):
         """If system has different locale, locale-gen should be called."""
-        spath = self.tmp_path("default-locale")
         m_subp.return_value = (None, None)
         locale = 'en_US.UTF-8'
-        util.write_file(spath, 'LANG=fr_FR.UTF-8', omode="w")
-        apply_locale(locale, sys_path=spath)
+        util.write_file(self.spath, 'LANG=fr_FR.UTF-8', omode="w")
+        self.distro.apply_locale(locale, out_fn=self.spath)
         self.assertEqual(
             [['locale-gen', locale],
-             ['update-locale', '--locale-file=' + spath, 'LANG=%s' % locale]],
+             ['update-locale', '--locale-file=' + self.spath,
+              'LANG=%s' % locale]],
             [p[0][0] for p in m_subp.call_args_list])
 
     def test_rerun_if_no_file(self, m_subp):
         """If system has no locale file, locale-gen should be called."""
-        spath = self.tmp_path("default-locale")
         m_subp.return_value = (None, None)
         locale = 'en_US.UTF-8'
-        apply_locale(locale, sys_path=spath)
+        self.distro.apply_locale(locale, out_fn=self.spath)
         self.assertEqual(
             [['locale-gen', locale],
-             ['update-locale', '--locale-file=' + spath, 'LANG=%s' % locale]],
+             ['update-locale', '--locale-file=' + self.spath,
+              'LANG=%s' % locale]],
             [p[0][0] for p in m_subp.call_args_list])
 
     def test_rerun_on_unset_system_locale(self, m_subp):
         """If system has unset locale, locale-gen should be called."""
         m_subp.return_value = (None, None)
-        spath = self.tmp_path("default-locale")
         locale = 'en_US.UTF-8'
-        util.write_file(spath, 'LANG=', omode="w")
-        apply_locale(locale, sys_path=spath)
+        util.write_file(self.spath, 'LANG=', omode="w")
+        self.distro.apply_locale(locale, out_fn=self.spath)
         self.assertEqual(
             [['locale-gen', locale],
-             ['update-locale', '--locale-file=' + spath, 'LANG=%s' % locale]],
+             ['update-locale', '--locale-file=' + self.spath,
+              'LANG=%s' % locale]],
             [p[0][0] for p in m_subp.call_args_list])
 
     def test_rerun_on_mismatched_keys(self, m_subp):
         """If key is LC_ALL and system has only LANG, rerun is expected."""
         m_subp.return_value = (None, None)
-        spath = self.tmp_path("default-locale")
         locale = 'en_US.UTF-8'
-        util.write_file(spath, 'LANG=', omode="w")
-        apply_locale(locale, sys_path=spath, keyname='LC_ALL')
+        util.write_file(self.spath, 'LANG=', omode="w")
+        self.distro.apply_locale(locale, out_fn=self.spath, keyname='LC_ALL')
         self.assertEqual(
             [['locale-gen', locale],
-             ['update-locale', '--locale-file=' + spath,
+             ['update-locale', '--locale-file=' + self.spath,
               'LC_ALL=%s' % locale]],
             [p[0][0] for p in m_subp.call_args_list])
 
@@ -69,14 +87,14 @@ class TestDebianApplyLocale(CiTestCase):
         """locale as None or "" is invalid and should raise ValueError."""
 
         with self.assertRaises(ValueError) as ctext_m:
-            apply_locale(None)
+            self.distro.apply_locale(None)
             m_subp.assert_not_called()
 
         self.assertEqual(
             'Failed to provide locale value.', str(ctext_m.exception))
 
         with self.assertRaises(ValueError) as ctext_m:
-            apply_locale("")
+            self.distro.apply_locale("")
             m_subp.assert_not_called()
         self.assertEqual(
             'Failed to provide locale value.', str(ctext_m.exception))
diff --git a/tests/unittests/test_distros/test_generic.py b/tests/unittests/test_distros/test_generic.py
index c9be277e..b355a19e 100644
--- a/tests/unittests/test_distros/test_generic.py
+++ b/tests/unittests/test_distros/test_generic.py
@@ -228,5 +228,21 @@ class TestGenericDistro(helpers.FilesystemMockingTestCase):
         os.symlink('/', '/run/systemd/system')
         self.assertFalse(d.uses_systemd())
 
+    @mock.patch('cloudinit.distros.debian.read_system_locale')
+    def test_get_locale_ubuntu(self, m_locale):
+        """Test ubuntu distro returns locale set to C.UTF-8"""
+        m_locale.return_value = 'C.UTF-8'
+        cls = distros.fetch("ubuntu")
+        d = cls("ubuntu", {}, None)
+        locale = d.get_locale()
+        self.assertEqual('C.UTF-8', locale)
+
+    def test_get_locale_rhel(self):
+        """Test rhel distro returns NotImplementedError exception"""
+        cls = distros.fetch("rhel")
+        d = cls("rhel", {}, None)
+        with self.assertRaises(NotImplementedError):
+            d.get_locale()
+
 
 # vi: ts=4 expandtab