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/distros/rhel.py b/cloudinit/distros/rhel.py
index f55d96f7..c72f7c17 100644
--- a/cloudinit/distros/rhel.py
+++ b/cloudinit/distros/rhel.py
@@ -11,6 +11,7 @@
 from cloudinit import distros
 from cloudinit import helpers
 from cloudinit import log as logging
+from cloudinit import subp
 from cloudinit import util
 
 from cloudinit.distros import rhel_util
@@ -83,7 +84,7 @@ class Distro(distros.Distro):
         if self.uses_systemd() and out_fn.endswith('/previous-hostname'):
             util.write_file(out_fn, hostname)
         elif self.uses_systemd():
-            util.subp(['hostnamectl', 'set-hostname', str(hostname)])
+            subp.subp(['hostnamectl', 'set-hostname', str(hostname)])
         else:
             host_cfg = {
                 'HOSTNAME': hostname,
@@ -108,7 +109,7 @@ class Distro(distros.Distro):
         if self.uses_systemd() and filename.endswith('/previous-hostname'):
             return util.load_file(filename).strip()
         elif self.uses_systemd():
-            (out, _err) = util.subp(['hostname'])
+            (out, _err) = subp.subp(['hostname'])
             if len(out):
                 return out
             else:
@@ -146,7 +147,7 @@ class Distro(distros.Distro):
         if pkgs is None:
             pkgs = []
 
-        if util.which('dnf'):
+        if subp.which('dnf'):
             LOG.debug('Using DNF for package management')
             cmd = ['dnf']
         else:
@@ -173,7 +174,7 @@ class Distro(distros.Distro):
         cmd.extend(pkglist)
 
         # Allow the output of this to flow outwards (ie not be captured)
-        util.subp(cmd, capture=False)
+        subp.subp(cmd, capture=False)
 
     def update_package_sources(self):
         self._runner.run("update-sources", self.package_command,