Merge lp:~smoser/curtin/trunk.run-in-chroot-revival into lp:~curtin-dev/curtin/trunk

[Scott Moser]

add support for RunInChroot in curtin.util

In my merge committed to trunk in revno 404, we dropped 'RunInChroot'.
That method was being used from curthooks in maas-images project to
make a chrootable target. In order to support installation of old images
that depend on RunInChroot we need to add the method back.

This does that by just utilizing ChrootableTarget. It also adds
a couple unit tests to ensure that this keeps working.

[lp:~smoser/curtin/trunk.run-in-chroot-revival]

422. By Scott Moser on 2016-08-29

fix tox, remove 'print'

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:422
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review: Approve (continuous-integration)

[Scott Moser (smoser)]

To address your concerns about subp tests, I added some more here.
https://code.launchpad.net/~smoser/curtin/trunk.subp-more-tests/+merge/304297

[Ryan Harper (raharper)]

Additional tests look good. We can merge this and those after.

review: Approve

=== modified file 'curtin/util.py'
--- curtin/util.py	2016-08-11 20:30:27 +0000
+++ curtin/util.py	2016-08-29 17:12:52 +0000
@@ -143,6 +143,8 @@
         a list of times to sleep in between retries.  After each failure
         subp will sleep for N seconds and then try again.  A value of [1, 3]
         means to run, sleep 1, run, sleep 3, run and then return exit code.
+    :param target:
+        run the command as 'chroot target <args>'
     """
     retries = []
     if "retries" in kwargs:
@@ -1082,4 +1084,12 @@
     return os.path.join(target, path)
 
 
+class RunInChroot(ChrootableTarget):
+    """Backwards compatibility for RunInChroot (LP: #1617375).
+    It needs to work like:
+        with RunInChroot("/target") as in_chroot:
+            in_chroot(["your", "chrooted", "command"])"""
+    __call__ = ChrootableTarget.subp
+
+
 # vi: ts=4 expandtab syntax=python
 
=== modified file 'tests/unittests/test_util.py'
--- tests/unittests/test_util.py	2016-08-08 18:40:17 +0000
+++ tests/unittests/test_util.py	2016-08-29 17:12:52 +0000
@@ -363,4 +363,35 @@
         self.assertEqual("/target/my/path/",
                          util.target_path("/target/", "///my/path/"))
 
+
+class TestRunInChroot(TestCase):
+    """Test the legacy 'RunInChroot'.
+
+    The test works by mocking ChrootableTarget's __enter__ to do nothing.
+    The assumptions made are:
+      a.) RunInChroot is a subclass of ChrootableTarget
+      b.) ChrootableTarget's __exit__ only un-does work that its __enter__
+          did.  Meaning for our mocked case, it does nothing."""
+
+    @mock.patch.object(util.ChrootableTarget, "__enter__", new=lambda a: a)
+    def test_run_in_chroot_with_target_slash(self):
+        with util.RunInChroot("/") as i:
+            out, err = i(['echo', 'HI MOM'], capture=True)
+        self.assertEqual('HI MOM\n', out)
+
+    @mock.patch.object(util.ChrootableTarget, "__enter__", new=lambda a: a)
+    @mock.patch("curtin.util.subp")
+    def test_run_in_chroot_with_target(self, m_subp):
+        my_stdout = "my output"
+        my_stderr = "my stderr"
+        cmd = ['echo', 'HI MOM']
+        target = "/foo"
+        m_subp.return_value = (my_stdout, my_stderr)
+        with util.RunInChroot(target) as i:
+            out, err = i(cmd)
+        self.assertEqual(my_stdout, out)
+        self.assertEqual(my_stderr, err)
+        m_subp.assert_called_with(cmd, target=target)
+
+
 # vi: ts=4 expandtab syntax=python