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. The main change here that allows this
is to support matching major and minor version up to X.Y.Z as
opposed to previously only matching the major version X.

Related-Bug: #1973303

Change-Id: I138f61312efb728544276483b1a459b9eeecafdb

charms_openstack/charm/core.py

@@ -1163,6 +1163,33 @@ 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
+
+        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 +1247,22 @@ 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 +885,36 @@ 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', '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([