Translate expected package names to installed ones

This patch fixes an issue that caused an internal error to the amphora
agent and led amphorae to transition to FAILURE state. The issue was
that on CentOS-based amphorae HAproxy package name is 'haproxy18' while
the expected package name is 'haproxy'.

The patch introduces a package name per distro map that is consulted
whenever a package has a different name than the one expected. If
there's a miss, it falls back to the expected package name.

Story: 2002958
Task: 22960

Change-Id: I59dfa3f9bd5974302ec72343444813232ec2ea02

octavia/amphorae/backends/agent/api_server/osutils.py

@@ -40,17 +40,30 @@
 
 class BaseOS(object):
 
+    PACKAGE_NAME_MAP = {}
+
     def __init__(self, os_name):
         self.os_name = os_name
 
+    @classmethod
+    def _get_subclasses(cls):
+        for subclass in cls.__subclasses__():
+            for sc in subclass._get_subclasses():
+                yield sc
+            yield subclass
+
     @classmethod
     def get_os_util(cls):
         os_name = distro.id()
-        for subclass in BaseOS.__subclasses__():
+        for subclass in cls._get_subclasses():
             if subclass.is_os_name(os_name):
                 return subclass(os_name)
         raise octavia_exceptions.InvalidAmphoraOperatingSystem(os_name=os_name)
 
+    @classmethod
+    def _map_package_name(cls, package_name):
+        return cls.PACKAGE_NAME_MAP.get(package_name, package_name)
+
     def get_network_interface_file(self, interface):
         if CONF.amphora_agent.agent_server_network_file:
             return CONF.amphora_agent.agent_server_network_file
@@ -223,7 +236,8 @@ def is_os_name(cls, os_name):
         return os_name in ['ubuntu']
 
     def cmd_get_version_of_installed_package(self, package_name):
-        return "dpkg-query -W -f=${{Version}} {name}".format(name=package_name)
+        name = self._map_package_name(package_name)
+        return "dpkg-query -W -f=${{Version}} {name}".format(name=name)
 
     def get_network_interface_file(self, interface):
         if CONF.amphora_agent.agent_server_network_file:
@@ -304,11 +318,11 @@ class RH(BaseOS):
 
     @classmethod
     def is_os_name(cls, os_name):
-        return os_name in ['fedora', 'rhel', 'centos']
+        return os_name in ['fedora', 'rhel']
 
     def cmd_get_version_of_installed_package(self, package_name):
-        return "rpm -q --queryformat %{{VERSION}} {name}".format(
-            name=package_name)
+        name = self._map_package_name(package_name)
+        return "rpm -q --queryformat %{{VERSION}} {name}".format(name=name)
 
     def get_network_interface_file(self, interface):
         if CONF.amphora_agent.agent_server_network_file:
@@ -458,3 +472,12 @@ def bring_interfaces_up(self, ip, primary_interface, secondary_interface):
 
     def has_ifup_all(self):
         return False
+
+
+class CentOS(RH):
+
+    PACKAGE_NAME_MAP = {'haproxy': 'haproxy18'}
+
+    @classmethod
+    def is_os_name(cls, os_name):
+        return os_name in ['centos']

octavia/tests/unit/amphorae/backends/agent/api_server/test_osutils.py

@@ -37,9 +37,13 @@ def setUp(self):
             self.ubuntu_os_util = osutils.BaseOS.get_os_util()
 
         with mock.patch('distro.id',
-                        return_value='centos'):
+                        return_value='rhel'):
             self.rh_os_util = osutils.BaseOS.get_os_util()
 
+        with mock.patch('distro.id',
+                        return_value='centos'):
+            self.centos_os_util = osutils.BaseOS.get_os_util()
+
     def test_get_os_util(self):
         with mock.patch('distro.id',
                         return_value='ubuntu'):
@@ -56,7 +60,7 @@ def test_get_os_util(self):
         with mock.patch('distro.id',
                         return_value='centos'):
             returned_cls = osutils.BaseOS.get_os_util()
-            self.assertIsInstance(returned_cls, osutils.RH)
+            self.assertIsInstance(returned_cls, osutils.CentOS)
         with mock.patch('distro.id',
                         return_value='FakeOS'):
             self.assertRaises(
@@ -169,6 +173,15 @@ def test_cmd_get_version_of_installed_package(self):
                            cmd_get_version_of_installed_package(package_name))
         self.assertEqual(rh_cmd, returned_rh_cmd)
 
+    def test_cmd_get_version_of_installed_package_mapped(self):
+        package_name = 'haproxy'
+        centos_cmd = "rpm -q --queryformat %{VERSION} haproxy18"
+
+        returned_centos_cmd = (
+            self.centos_os_util.cmd_get_version_of_installed_package(
+                package_name))
+        self.assertEqual(centos_cmd, returned_centos_cmd)
+
     def test_has_ifup_all(self):
         self.assertTrue(self.base_os_util.has_ifup_all())
         self.assertTrue(self.ubuntu_os_util.has_ifup_all())