Merge pull request #1906 from bboozzoo/bboozzoo/snap-helpers

subiquitycore: helpers for probing for snap execution environment

subiquitycore/snap.py

@@ -0,0 +1,33 @@
+# Copyright 2024 Canonical, Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+
+# Returns true if the current execution environment is inside a snap.
+def is_snap():
+    return os.getenv("SNAP_CONFINEMENT") is not None
+
+
+# Returns true if the current execution environment is inside a strictly
+# confined snap.
+def is_snap_strictly_confined():
+    return os.getenv("SNAP_CONFINEMENT", "classic") == "strict"
+
+
+# Returns the snap name if the current execution context is inside a snap,
+# otherwise None.
+def snap_name():
+    return os.getenv("SNAP_INSTANCE_NAME")

subiquitycore/tests/test_snap.py

@@ -0,0 +1,58 @@
+# Copyright 2024 Canonical, Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import unittest
+from unittest.mock import patch
+
+from subiquitycore import snap
+
+
+class TestSnap(unittest.TestCase):
+    @patch("os.getenv", return_value=None)
+    def test_is_snap(self, os_getenv):
+        self.assertFalse(snap.is_snap())
+        os_getenv.assert_called_with("SNAP_CONFINEMENT")
+        os_getenv.reset_mock()
+
+        os_getenv.return_value = "strict"
+        self.assertTrue(snap.is_snap())
+        os_getenv.assert_called_with("SNAP_CONFINEMENT")
+        os_getenv.reset_mock()
+
+        os_getenv.return_value = "classic"
+        self.assertTrue(snap.is_snap())
+        os_getenv.assert_called_with("SNAP_CONFINEMENT")
+        os_getenv.reset_mock()
+
+    @patch("os.getenv", return_value=None)
+    def test_snap_confinement(self, os_getenv):
+        self.assertFalse(snap.is_snap_strictly_confined())
+        os_getenv.assert_called_with("SNAP_CONFINEMENT", "classic")
+        os_getenv.reset_mock()
+
+        os_getenv.return_value = "strict"
+        self.assertTrue(snap.is_snap_strictly_confined())
+
+        os_getenv.return_value = "classic"
+        self.assertFalse(snap.is_snap_strictly_confined())
+
+    @patch("os.getenv", return_value=None)
+    def test_snap_name(self, os_getenv):
+        self.assertIsNone(snap.snap_name())
+        os_getenv.assert_called_with("SNAP_INSTANCE_NAME")
+        os_getenv.reset_mock()
+
+        os_getenv.return_value = "console-conf"
+        self.assertEqual(snap.snap_name(), "console-conf")