Support same pkg version for multiple releases

It is possible for the version of a package to remain the same
across multiple releases of openstack so this adds support to
get_os_codename_package() to allow this. If releases A, B and C
have version N and we are on release B this will return release
C so that it does not look like there is an upgrade necessary.

Change-Id: I138f61312efb728544276483b1a459b9eeecafdb

charms_openstack/charm/core.py

@@ -1163,6 +1163,36 @@ class BaseOpenStackCharmActions(object):
 
         return vers
 
+    def get_closest_release_match(self, package_version, codenames):
+        # Multiple releases can share the same version of the package so this
+        # collects contiguous versions, maintaining order then picks the most
+        # recent version that is less than or equal to what is installed.
+        reversed_codenames = collections.OrderedDict(
+            reversed(codenames.items()))
+        vr_match = None
+        splitver = package_version.split('.')
+        for dotpos in reversed(range(3)):
+            if dotpos >= len(splitver):
+                continue
+
+            ver_pfix = '.'.join(splitver[0:dotpos + 1])
+            for ver, rname in reversed_codenames.items():
+                if not ver.startswith(ver_pfix):
+                    continue
+
+                if ((vr_match is None or ver > vr_match[0]) and
+                        ver <= package_version):
+                    vr_match = (ver, rname)
+                    break
+
+            if vr_match:
+                break
+
+        if vr_match and isinstance(vr_match[1], list):
+            vr_match = vr_match[0], vr_match[1][-1]
+
+        return vr_match
+
     def get_os_codename_package(self, package, codenames, fatal=True,
                                 apt_cache_sufficient=False):
         """Derive OpenStack release codename from a package.
@@ -1220,20 +1250,22 @@ class BaseOpenStackCharmActions(object):
             if codename:
                 return codename
 
-            vers = self.get_package_version(
+            package_version = self.get_package_version(
                 package,
                 apt_cache_sufficient=apt_cache_sufficient)
-            # Generate a major version number for newer semantic
-            # versions of openstack projects
-            major_vers = vers.split('.')[0]
         except Exception:
             if fatal:
                 raise
             else:
                 return None
-        if (package in codenames and
-                major_vers in codenames[package]):
-            return codenames[package][major_vers]
+
+        if package not in codenames:
+            return
+
+        vr_match = self.get_closest_release_match(package_version,
+                                                  codenames[package])
+        if vr_match:
+            return vr_match[1]
 
     def get_os_version_snap(self, snap, fatal=True):
         """Derive OpenStack version number from an installed snap.

unit_tests/charms_openstack/charm/test_core.py

@@ -885,6 +885,37 @@ class TestMyOpenStackCharm(BaseOpenStackCharmTest):
         for call in self.render.call_args_list:
             self.assertTrue(call[1]['context'])
 
+    def test_get_closest_release_match(self):
+        codenames = collections.OrderedDict([('3.9', 'ussuri'),
+                                             ('4.0', 'victoria'),
+                                             ('4.0.1',
+                                              ['wallaby', 'xena', 'yoga'])])
+
+        self.assertEqual(self.target.get_closest_release_match('4',
+                                                               codenames),
+                         None)
+
+        self.assertEqual(self.target.get_closest_release_match('4.0',
+                                                               codenames),
+                         ('4.0', 'victoria'))
+
+        self.assertEqual(self.target.get_closest_release_match('4.0.1',
+                                                               codenames),
+                         ('4.0.1', 'yoga'))
+
+        self.assertEqual(self.target.get_closest_release_match('4.0.2',
+                                                               codenames),
+                         ('4.0.1', 'yoga'))
+
+        codenames['4.0.3'] = 'yoga'
+        self.assertEqual(self.target.get_closest_release_match('4.0.2',
+                                                               codenames),
+                         ('4.0.1', 'yoga'))
+
+        self.assertEqual(self.target.get_closest_release_match('4.0.1.1',
+                                                               codenames),
+                         ('4.0.1', 'yoga'))
+
     def test_get_os_codename_package(self):
         codenames = {
             'testpkg': collections.OrderedDict([