Move subp into its own module. (#416)

This was painful, but it finishes a TODO from cloudinit/subp.py.

It moves the following from util to subp:
  ProcessExecutionError
  subp
  which
  target_path

I moved subp_blob_in_tempfile into cc_chef, which is its only caller.
That saved us from having to deal with it using write_file
and temp_utils from subp (which does not import any cloudinit things now).

It is arguable that 'target_path' could be moved to a 'path_utils' or
something, but in order to use it from subp and also from utils,
we had to get it out of utils.

2 files changed, 9 insertions, 8 deletions

diff --git a/cloudinit/net/tests/test_dhcp.py b/cloudinit/net/tests/test_dhcp.py
index 7768da7c..d4881592 100644
--- a/cloudinit/net/tests/test_dhcp.py
+++ b/cloudinit/net/tests/test_dhcp.py
@@ -266,7 +266,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
             'Skip dhcp_discovery: nic idontexist not found in get_devicelist.',
             self.logs.getvalue())
 
-    @mock.patch('cloudinit.net.dhcp.util.which')
+    @mock.patch('cloudinit.net.dhcp.subp.which')
     @mock.patch('cloudinit.net.dhcp.find_fallback_nic')
     def test_absent_dhclient_command(self, m_fallback, m_which):
         """When dhclient doesn't exist in the OS, log the issue and no-op."""
@@ -279,7 +279,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
 
     @mock.patch('cloudinit.temp_utils.os.getuid')
     @mock.patch('cloudinit.net.dhcp.dhcp_discovery')
-    @mock.patch('cloudinit.net.dhcp.util.which')
+    @mock.patch('cloudinit.net.dhcp.subp.which')
     @mock.patch('cloudinit.net.dhcp.find_fallback_nic')
     def test_dhclient_run_with_tmpdir(self, m_fback, m_which, m_dhcp, m_uid):
         """maybe_perform_dhcp_discovery passes tmpdir to dhcp_discovery."""
@@ -302,7 +302,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
 
     @mock.patch('time.sleep', mock.MagicMock())
     @mock.patch('cloudinit.net.dhcp.os.kill')
-    @mock.patch('cloudinit.net.dhcp.util.subp')
+    @mock.patch('cloudinit.net.dhcp.subp.subp')
     def test_dhcp_discovery_run_in_sandbox_warns_invalid_pid(self, m_subp,
                                                              m_kill):
         """dhcp_discovery logs a warning when pidfile contains invalid content.
@@ -337,7 +337,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
     @mock.patch('cloudinit.net.dhcp.util.get_proc_ppid')
     @mock.patch('cloudinit.net.dhcp.os.kill')
     @mock.patch('cloudinit.net.dhcp.util.wait_for_files')
-    @mock.patch('cloudinit.net.dhcp.util.subp')
+    @mock.patch('cloudinit.net.dhcp.subp.subp')
     def test_dhcp_discovery_run_in_sandbox_waits_on_lease_and_pid(self,
                                                                   m_subp,
                                                                   m_wait,
@@ -364,7 +364,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
 
     @mock.patch('cloudinit.net.dhcp.util.get_proc_ppid')
     @mock.patch('cloudinit.net.dhcp.os.kill')
-    @mock.patch('cloudinit.net.dhcp.util.subp')
+    @mock.patch('cloudinit.net.dhcp.subp.subp')
     def test_dhcp_discovery_run_in_sandbox(self, m_subp, m_kill, m_getppid):
         """dhcp_discovery brings up the interface and runs dhclient.
 
@@ -529,7 +529,7 @@ class TestEphemeralDhcpNoNetworkSetup(HttprettyTestCase):
         # Ensure that no teardown happens:
         m_dhcp.assert_not_called()
 
-    @mock.patch('cloudinit.net.dhcp.util.subp')
+    @mock.patch('cloudinit.net.dhcp.subp.subp')
     @mock.patch('cloudinit.net.dhcp.maybe_perform_dhcp_discovery')
     def test_ephemeral_dhcp_setup_network_if_url_connectivity(
             self, m_dhcp, m_subp):
diff --git a/cloudinit/net/tests/test_init.py b/cloudinit/net/tests/test_init.py
index 835ed807..1c0a16a8 100644
--- a/cloudinit/net/tests/test_init.py
+++ b/cloudinit/net/tests/test_init.py
@@ -14,7 +14,8 @@ import requests
 import cloudinit.net as net
 from cloudinit import safeyaml as yaml
 from cloudinit.tests.helpers import CiTestCase, HttprettyTestCase
-from cloudinit.util import ProcessExecutionError, ensure_file, write_file
+from cloudinit.subp import ProcessExecutionError
+from cloudinit.util import ensure_file, write_file
 
 
 class TestSysDevPath(CiTestCase):
@@ -541,7 +542,7 @@ class TestInterfaceHasOwnMAC(CiTestCase):
             net.interface_has_own_mac('eth1', strict=True)
 
 
-@mock.patch('cloudinit.net.util.subp')
+@mock.patch('cloudinit.net.subp.subp')
 class TestEphemeralIPV4Network(CiTestCase):
 
     with_logs = True