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.

1 files changed, 5 insertions, 4 deletions

diff --git a/cloudinit/config/cc_grub_dpkg.py b/cloudinit/config/cc_grub_dpkg.py
index 7888464e..eb03c664 100644
--- a/cloudinit/config/cc_grub_dpkg.py
+++ b/cloudinit/config/cc_grub_dpkg.py
@@ -43,8 +43,9 @@ seeded with empty values, and install_devices_empty is set to true.
 
 import os
 
+from cloudinit import subp
 from cloudinit import util
-from cloudinit.util import ProcessExecutionError
+from cloudinit.subp import ProcessExecutionError
 
 distros = ['ubuntu', 'debian']
 
@@ -59,7 +60,7 @@ def fetch_idevs(log):
 
     try:
         # get the root disk where the /boot directory resides.
-        disk = util.subp(['grub-probe', '-t', 'disk', '/boot'],
+        disk = subp.subp(['grub-probe', '-t', 'disk', '/boot'],
                          capture=True)[0].strip()
     except ProcessExecutionError as e:
         # grub-common may not be installed, especially on containers
@@ -84,7 +85,7 @@ def fetch_idevs(log):
 
     try:
         # check if disk exists and use udevadm to fetch symlinks
-        devices = util.subp(
+        devices = subp.subp(
             ['udevadm', 'info', '--root', '--query=symlink', disk],
             capture=True
         )[0].strip().split()
@@ -135,7 +136,7 @@ def handle(name, cfg, _cloud, log, _args):
               (idevs, idevs_empty))
 
     try:
-        util.subp(['debconf-set-selections'], dconf_sel)
+        subp.subp(['debconf-set-selections'], dconf_sel)
     except Exception:
         util.logexc(log, "Failed to run debconf-set-selections for grub-dpkg")