Ensure util.get_architecture() runs only once (#172)

* Ensure util.get_architecture() runs only once

util.get_architecture() recently was wrapped using python3's lru_cache()
which will cache the result so we only invoke 'dpkg --print-architecture'
once.  In practice, cloud-init.log will show multiple invocations of the
command.  The source of this was that the debian Distro object implements
the get_primary_arch() with this command, but it was not calling it from
util, but issuing a util.subp() directly.  This branch also updates
cc_apt_configure methods to fetch the arch value from the distro class,
and then ensure that the methods apt_configure calls pass the arch value
around.

* utils: remove lsb_release and get_architecture wrappers

The original lsb_release wrapper was used to prevent polluting the
single value we cached, however lru_cache() already handles this
case by using args, kwargs values to cache different calls to the
method.

* rename_apt_list: use all positional parameters

4 files changed, 9 insertions, 17 deletions

diff --git a/cloudinit/config/cc_apt_configure.py b/cloudinit/config/cc_apt_configure.py
index f01e2aaf..4a3aed36 100644
--- a/cloudinit/config/cc_apt_configure.py
+++ b/cloudinit/config/cc_apt_configure.py
@@ -309,7 +309,7 @@ def apply_apt(cfg, cloud, target):
 
     if util.is_false(cfg.get('preserve_sources_list', False)):
         generate_sources_list(cfg, release, mirrors, cloud)
-        rename_apt_lists(mirrors, target)
+        rename_apt_lists(mirrors, target, arch)
 
     try:
         apply_apt_config(cfg, APT_PROXY_FN, APT_CONFIG_FN)
@@ -427,9 +427,9 @@ def mirrorurl_to_apt_fileprefix(mirror):
     return string
 
 
-def rename_apt_lists(new_mirrors, target=None):
+def rename_apt_lists(new_mirrors, target, arch):
     """rename_apt_lists - rename apt lists to preserve old cache data"""
-    default_mirrors = get_default_mirrors(util.get_architecture(target))
+    default_mirrors = get_default_mirrors(arch)
 
     pre = util.target_path(target, APT_LISTS)
     for (name, omirror) in default_mirrors.items():
diff --git a/cloudinit/distros/debian.py b/cloudinit/distros/debian.py
index cf082c73..79268371 100644
--- a/cloudinit/distros/debian.py
+++ b/cloudinit/distros/debian.py
@@ -205,8 +205,7 @@ class Distro(distros.Distro):
                          ["update"], freq=PER_INSTANCE)
 
     def get_primary_arch(self):
-        (arch, _err) = util.subp(['dpkg', '--print-architecture'])
-        return str(arch).strip()
+        return util.get_architecture()
 
 
 def _get_wrapper_prefix(cmd, mode):
diff --git a/cloudinit/util.py b/cloudinit/util.py
index 76d7db78..87480767 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -86,7 +86,7 @@ def get_architecture(target=None):
 
 
 @lru_cache()
-def _lsb_release(target=None):
+def lsb_release(target=None):
     fmap = {'Codename': 'codename', 'Description': 'description',
             'Distributor ID': 'id', 'Release': 'release'}
 
@@ -109,14 +109,6 @@ def _lsb_release(target=None):
     return data
 
 
-def lsb_release(target=None):
-    if target_path(target) != "/":
-        # do not use or update cache if target is provided
-        return _lsb_release(target)
-
-    return _lsb_release()
-
-
 def target_path(target, path=None):
     # return 'path' inside target, accepting target as None
     if target in (None, ""):
diff --git a/tests/unittests/test_handler/test_handler_apt_source_v3.py b/tests/unittests/test_handler/test_handler_apt_source_v3.py
index 2f21b6dc..dcffbe13 100644
--- a/tests/unittests/test_handler/test_handler_apt_source_v3.py
+++ b/tests/unittests/test_handler/test_handler_apt_source_v3.py
@@ -487,7 +487,7 @@ class TestAptSourceConfig(t_help.FilesystemMockingTestCase):
         with mock.patch.object(os, 'rename') as mockren:
             with mock.patch.object(glob, 'glob',
                                    return_value=[fromfn]):
-                cc_apt_configure.rename_apt_lists(mirrors, TARGET)
+                cc_apt_configure.rename_apt_lists(mirrors, TARGET, arch)
 
         mockren.assert_any_call(fromfn, tofn)
 
@@ -496,7 +496,8 @@ class TestAptSourceConfig(t_help.FilesystemMockingTestCase):
         target = os.path.join(self.tmp, "rename_non_slash")
         apt_lists_d = os.path.join(target, "./" + cc_apt_configure.APT_LISTS)
 
-        m_get_architecture.return_value = 'amd64'
+        arch = 'amd64'
+        m_get_architecture.return_value = arch
 
         mirror_path = "some/random/path/"
         primary = "http://test.ubuntu.com/" + mirror_path
@@ -532,7 +533,7 @@ class TestAptSourceConfig(t_help.FilesystemMockingTestCase):
             fpath = os.path.join(apt_lists_d, opre + suff)
             util.write_file(fpath, content=fpath)
 
-        cc_apt_configure.rename_apt_lists(mirrors, target)
+        cc_apt_configure.rename_apt_lists(mirrors, target, arch)
         found = sorted(os.listdir(apt_lists_d))
         self.assertEqual(expected, found)