Merge ~mpontillo/maas:rack-version-utils into maas:master

[Mike Pontillo]

Make version check utilities work for the rack.

This allows rack-only installations to determine their version.

Also moves code to determine MAAS version to the src/provisioningserver.

[Newell Jensen (newell-jensen)]

Looks good. Just one small suggestion.

review: Approve

Unmerged commits

7adaa6b... by Mike Pontillo on 2017-07-12

Make version check utilities work for the rack.

This allows rack-only installations to determine their version.

5d95ec9... by Mike Pontillo on 2017-07-12

Move code to determine MAAS version to the rack.

diff --git a/src/provisioningserver/utils/tests/test_version.py b/src/provisioningserver/utils/tests/test_version.py
index 2f6c6d3..e2a8419 100644
--- a/src/provisioningserver/utils/tests/test_version.py
+++ b/src/provisioningserver/utils/tests/test_version.py
@@ -58,12 +58,24 @@ class TestGetVersionFromAPT(MAASTestCase):
         package = MagicMock()
         package.current_ver.ver_str = sentinel.ver_str
         mock_cache = {
-            version.REGION_PACKAGE_NAME: package,
+            version.RACK_PACKAGE_NAME: package
             }
         self.patch(version.apt_pkg, "Cache").return_value = mock_cache
         self.assertIs(
             sentinel.ver_str,
-            version.get_version_from_apt(version.REGION_PACKAGE_NAME))
+            version.get_version_from_apt(version.RACK_PACKAGE_NAME))
+
+    def test__returns_ver_str_from_second_package_if_first_not_found(self):
+        package = MagicMock()
+        package.current_ver.ver_str = sentinel.ver_str
+        mock_cache = {
+            version.REGION_PACKAGE_NAME: package,
+        }
+        self.patch(version.apt_pkg, "Cache").return_value = mock_cache
+        self.assertIs(
+            sentinel.ver_str,
+            version.get_version_from_apt(
+                version.RACK_PACKAGE_NAME, version.REGION_PACKAGE_NAME))
 
 
 class TestGetMAASBranchVersion(MAASTestCase):
@@ -134,7 +146,8 @@ class TestGetMAASVersion(TestVersionTestCase):
         self.expectThat(
             version.get_maas_version(), Is(sentinel.version))
         self.expectThat(
-            mock_apt, MockCalledOnceWith(version.REGION_PACKAGE_NAME))
+            mock_apt, MockCalledOnceWith(
+                version.RACK_PACKAGE_NAME, version.REGION_PACKAGE_NAME))
 
     def test__uses_snappy_get_snap_version(self):
         self.patch(snappy, 'running_in_snap').return_value = True
@@ -268,7 +281,8 @@ class TestVersionMethodsCached(TestVersionTestCase):
         self.assertEqual(first_return_value, second_return_value)
         # Apt has only been called once.
         self.expectThat(
-            mock_apt, MockCalledOnceWith(version.REGION_PACKAGE_NAME))
+            mock_apt, MockCalledOnceWith(
+                version.RACK_PACKAGE_NAME, version.REGION_PACKAGE_NAME))
 
 
 class TestGetMAASVersionTuple(MAASTestCase):
diff --git a/src/provisioningserver/utils/version.py b/src/provisioningserver/utils/version.py
index 4db93fc..2fedc08 100644
--- a/src/provisioningserver/utils/version.py
+++ b/src/provisioningserver/utils/version.py
@@ -26,11 +26,12 @@ if not snappy.running_in_snap():
 
 # Name of maas package to get version from.
 REGION_PACKAGE_NAME = "maas-region-api"
+RACK_PACKAGE_NAME = "maas-rack-controller"
 
 
-def get_version_from_apt(package):
-    """Return the version output from `apt_pkg.Cache` for the given package or
-    an error message if the package data is not valid."""
+def get_version_from_apt(*packages):
+    """Return the version output from `apt_pkg.Cache` for the given package(s),
+     or log an error message if the package data is not valid."""
     try:
         cache = apt_pkg.Cache(None)
     except SystemError:
@@ -40,9 +41,11 @@ def get_version_from_apt(package):
         return ""
 
     version = None
-    if package in cache:
-        apt_package = cache[package]
-        version = apt_package.current_ver
+    for package in packages:
+        if package in cache:
+            apt_package = cache[package]
+            version = apt_package.current_ver
+            break
 
     return version.ver_str if version is not None else ""
 
@@ -86,7 +89,7 @@ def get_maas_version():
     if snappy.running_in_snap():
         return snappy.get_snap_version()
     else:
-        return get_version_from_apt(REGION_PACKAGE_NAME)
+        return get_version_from_apt(RACK_PACKAGE_NAME, REGION_PACKAGE_NAME)
 
 
 @lru_cache(maxsize=1)