util: add get_linux_distro function to replace platform.dist

Allow the user to set the distribution with --distro argument to setup.py.
Fall back is to read /etc/os-release. Final backup is to use
platform.dist() Python function. The platform.dist() function is
deprecated and will be removed in Python 3.7

LP: #1745235

3 files changed, 127 insertions, 7 deletions

diff --git a/cloudinit/tests/test_util.py b/cloudinit/tests/test_util.py
index 3c05a437..17853fc7 100644
--- a/cloudinit/tests/test_util.py
+++ b/cloudinit/tests/test_util.py
@@ -3,11 +3,12 @@
 """Tests for cloudinit.util"""
 
 import logging
-from textwrap import dedent
+import platform
 
 import cloudinit.util as util
 
 from cloudinit.tests.helpers import CiTestCase, mock
+from textwrap import dedent
 
 LOG = logging.getLogger(__name__)
 
@@ -16,6 +17,29 @@ MOUNT_INFO = [
     '153 68 254:0 / /home rw,relatime shared:101 - xfs /dev/sda2 rw,attr2'
 ]
 
+OS_RELEASE_SLES = dedent("""\
+    NAME="SLES"\n
+    VERSION="12-SP3"\n
+    VERSION_ID="12.3"\n
+    PRETTY_NAME="SUSE Linux Enterprise Server 12 SP3"\n
+    ID="sles"\nANSI_COLOR="0;32"\n
+    CPE_NAME="cpe:/o:suse:sles:12:sp3"\n
+""")
+
+OS_RELEASE_UBUNTU = dedent("""\
+    NAME="Ubuntu"\n
+    VERSION="16.04.3 LTS (Xenial Xerus)"\n
+    ID=ubuntu\n
+    ID_LIKE=debian\n
+    PRETTY_NAME="Ubuntu 16.04.3 LTS"\n
+    VERSION_ID="16.04"\n
+    HOME_URL="http://www.ubuntu.com/"\n
+    SUPPORT_URL="http://help.ubuntu.com/"\n
+    BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"\n
+    VERSION_CODENAME=xenial\n
+    UBUNTU_CODENAME=xenial\n
+""")
+
 
 class FakeCloud(object):
 
@@ -261,4 +285,56 @@ class TestUdevadmSettle(CiTestCase):
         self.assertRaises(util.ProcessExecutionError, util.udevadm_settle)
 
 
+@mock.patch('os.path.exists')
+class TestGetLinuxDistro(CiTestCase):
+
+    @classmethod
+    def os_release_exists(self, path):
+        """Side effect function"""
+        if path == '/etc/os-release':
+            return 1
+
+    @mock.patch('cloudinit.util.load_file')
+    def test_get_linux_distro_quoted_name(self, m_os_release, m_path_exists):
+        """Verify we get the correct name if the os-release file has
+        the distro name in quotes"""
+        m_os_release.return_value = OS_RELEASE_SLES
+        m_path_exists.side_effect = TestGetLinuxDistro.os_release_exists
+        dist = util.get_linux_distro()
+        self.assertEqual(('sles', '12.3', platform.machine()), dist)
+
+    @mock.patch('cloudinit.util.load_file')
+    def test_get_linux_distro_bare_name(self, m_os_release, m_path_exists):
+        """Verify we get the correct name if the os-release file does not
+        have the distro name in quotes"""
+        m_os_release.return_value = OS_RELEASE_UBUNTU
+        m_path_exists.side_effect = TestGetLinuxDistro.os_release_exists
+        dist = util.get_linux_distro()
+        self.assertEqual(('ubuntu', '16.04', platform.machine()), dist)
+
+    @mock.patch('platform.dist')
+    def test_get_linux_distro_no_data(self, m_platform_dist, m_path_exists):
+        """Verify we get no information if os-release does not exist"""
+        m_platform_dist.return_value = ('', '', '')
+        m_path_exists.return_value = 0
+        dist = util.get_linux_distro()
+        self.assertEqual(('', '', ''), dist)
+
+    @mock.patch('platform.dist')
+    def test_get_linux_distro_no_impl(self, m_platform_dist, m_path_exists):
+        """Verify we get an empty tuple when no information exists and
+        Exceptions are not propagated"""
+        m_platform_dist.side_effect = Exception()
+        m_path_exists.return_value = 0
+        dist = util.get_linux_distro()
+        self.assertEqual(('', '', ''), dist)
+
+    @mock.patch('platform.dist')
+    def test_get_linux_distro_plat_data(self, m_platform_dist, m_path_exists):
+        """Verify we get the correct platform information"""
+        m_platform_dist.return_value = ('foo', '1.1', 'aarch64')
+        m_path_exists.return_value = 0
+        dist = util.get_linux_distro()
+        self.assertEqual(('foo', '1.1', 'aarch64'), dist)
+
 # vi: ts=4 expandtab
diff --git a/cloudinit/util.py b/cloudinit/util.py
index 6ea6ca76..d9b61cfe 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -576,6 +576,39 @@ def get_cfg_option_int(yobj, key, default=0):
     return int(get_cfg_option_str(yobj, key, default=default))
 
 
+def get_linux_distro():
+    distro_name = ''
+    distro_version = ''
+    if os.path.exists('/etc/os-release'):
+        os_release = load_file('/etc/os-release')
+        for line in os_release.splitlines():
+            if line.strip().startswith('ID='):
+                distro_name = line.split('=')[-1]
+                distro_name = distro_name.replace('"', '')
+            if line.strip().startswith('VERSION_ID='):
+                # Lets hope for the best that distros stay consistent ;)
+                distro_version = line.split('=')[-1]
+                distro_version = distro_version.replace('"', '')
+    else:
+        dist = ('', '', '')
+        try:
+            # Will be removed in 3.7
+            dist = platform.dist()  # pylint: disable=W1505
+        except Exception:
+            pass
+        finally:
+            found = None
+            for entry in dist:
+                if entry:
+                    found = 1
+            if not found:
+                LOG.warning('Unable to determine distribution, template '
+                            'expansion may have unexpected results')
+        return dist
+
+    return (distro_name, distro_version, platform.machine())
+
+
 def system_info():
     info = {
         'platform': platform.platform(),
@@ -583,19 +616,19 @@ def system_info():
         'release': platform.release(),
         'python': platform.python_version(),
         'uname': platform.uname(),
-        'dist': platform.dist(),  # pylint: disable=W1505
+        'dist': get_linux_distro()
     }
     system = info['system'].lower()
     var = 'unknown'
     if system == "linux":
         linux_dist = info['dist'][0].lower()
-        if linux_dist in ('centos', 'fedora', 'debian'):
+        if linux_dist in ('centos', 'debian', 'fedora', 'rhel', 'suse'):
             var = linux_dist
         elif linux_dist in ('ubuntu', 'linuxmint', 'mint'):
             var = 'ubuntu'
         elif linux_dist == 'redhat':
             var = 'rhel'
-        elif linux_dist == 'suse':
+        elif linux_dist in ('opensuse', 'sles'):
             var = 'suse'
         else:
             var = 'linux'
diff --git a/setup.py b/setup.py
index 85b2337a..5ed8eae2 100755
--- a/setup.py
+++ b/setup.py
@@ -25,7 +25,7 @@ from distutils.errors import DistutilsArgError
 import subprocess
 
 RENDERED_TMPD_PREFIX = "RENDERED_TEMPD"
-
+VARIANT = None
 
 def is_f(p):
     return os.path.isfile(p)
@@ -114,10 +114,20 @@ def render_tmpl(template):
     atexit.register(shutil.rmtree, tmpd)
     bname = os.path.basename(template).rstrip(tmpl_ext)
     fpath = os.path.join(tmpd, bname)
-    tiny_p([sys.executable, './tools/render-cloudcfg', template, fpath])
+    if VARIANT:
+        tiny_p([sys.executable, './tools/render-cloudcfg', '--variant',
+            VARIANT, template, fpath])
+    else:
+        tiny_p([sys.executable, './tools/render-cloudcfg', template, fpath])
     # return path relative to setup.py
     return os.path.join(os.path.basename(tmpd), bname)
 
+# User can set the variant for template rendering
+if '--distro' in sys.argv:
+    idx = sys.argv.index('--distro')
+    VARIANT = sys.argv[idx+1]
+    del sys.argv[idx+1]
+    sys.argv.remove('--distro')
 
 INITSYS_FILES = {
     'sysvinit': [f for f in glob('sysvinit/redhat/*') if is_f(f)],
@@ -260,7 +270,7 @@ requirements = read_requires()
 setuptools.setup(
     name='cloud-init',
     version=get_version(),
-    description='EC2 initialisation magic',
+    description='Cloud instance initialisation magic',
     author='Scott Moser',
     author_email='scott.moser@canonical.com',
     url='http://launchpad.net/cloud-init/',
@@ -277,4 +287,5 @@ setuptools.setup(
     }
 )
 
+
 # vi: ts=4 expandtab