Merge lp:~james-page/charm-helpers/is-container into lp:charm-helpers

[James Page]

[lp:~james-page/charm-helpers/is-container]

654. By James Page on 2016-11-09

Remove ambiguity in container detection

[Liam Young (gnuoy)]

LGTM, merging

review: Approve

=== modified file 'charmhelpers/core/host.py'
--- charmhelpers/core/host.py	2016-08-11 15:47:44 +0000
+++ charmhelpers/core/host.py	2016-11-09 11:15:35 +0000
@@ -732,3 +732,20 @@
                     assert unit == 'kB', 'Unknown unit'
                     return int(value) * 1024  # Classic, not KiB.
         raise NotImplementedError()
+
+
+UPSTART_CONTAINER_TYPE = '/run/container_type'
+
+
+def is_container():
+    """Determine whether unit is running in a container
+
+    @return: boolean indicating if unit is in a container
+    """
+    if init_is_systemd():
+        # Detect using systemd-detect-virt
+        return subprocess.call(['systemd-detect-virt',
+                                '--container']) == 0
+    else:
+        # Detect using upstart container file marker
+        return os.path.exists(UPSTART_CONTAINER_TYPE)

=== modified file 'tests/core/test_host.py'
--- tests/core/test_host.py	2016-08-11 15:47:44 +0000
+++ tests/core/test_host.py	2016-11-09 11:15:35 +0000
@@ -1682,3 +1682,51 @@
             mock_file.readlines.return_value = raw.splitlines()
             self.assertEqual(host.get_total_ram(), 7266414592)  # 7GB
             mock_open.assert_called_once_with('/proc/meminfo', 'r')
+
+    @patch.object(host, 'os')
+    @patch.object(host, 'init_is_systemd')
+    @patch('subprocess.call')
+    def test_is_container_with_systemd_container(self,
+                                                 call,
+                                                 init_is_systemd,
+                                                 mock_os):
+        init_is_systemd.return_value = True
+        call.return_value = 0
+        self.assertTrue(host.is_container())
+        call.assert_called_with(['systemd-detect-virt', '--container'])
+
+    @patch.object(host, 'os')
+    @patch.object(host, 'init_is_systemd')
+    @patch('subprocess.call')
+    def test_is_container_with_systemd_non_container(self,
+                                                     call,
+                                                     init_is_systemd,
+                                                     mock_os):
+        init_is_systemd.return_value = True
+        call.return_value = 1
+        self.assertFalse(host.is_container())
+        call.assert_called_with(['systemd-detect-virt', '--container'])
+
+    @patch.object(host, 'os')
+    @patch.object(host, 'init_is_systemd')
+    @patch('subprocess.call')
+    def test_is_container_with_upstart_container(self,
+                                                 call,
+                                                 init_is_systemd,
+                                                 mock_os):
+        init_is_systemd.return_value = False
+        mock_os.path.exists.return_value = True
+        self.assertTrue(host.is_container())
+        mock_os.path.exists.assert_called_with('/run/container_type')
+
+    @patch.object(host, 'os')
+    @patch.object(host, 'init_is_systemd')
+    @patch('subprocess.call')
+    def test_is_container_with_upstart_not_container(self,
+                                                     call,
+                                                     init_is_systemd,
+                                                     mock_os):
+        init_is_systemd.return_value = False
+        mock_os.path.exists.return_value = False
+        self.assertFalse(host.is_container())
+        mock_os.path.exists.assert_called_with('/run/container_type')