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/sources/helpers/digitalocean.py b/cloudinit/sources/helpers/digitalocean.py
index 0e7cccac..f5bbe46a 100644
--- a/cloudinit/sources/helpers/digitalocean.py
+++ b/cloudinit/sources/helpers/digitalocean.py
@@ -8,6 +8,7 @@ import random
 from cloudinit import log as logging
 from cloudinit import net as cloudnet
 from cloudinit import url_helper
+from cloudinit import subp
 from cloudinit import util
 
 NIC_MAP = {'public': 'eth0', 'private': 'eth1'}
@@ -36,14 +37,14 @@ def assign_ipv4_link_local(nic=None):
     ip_addr_cmd = ['ip', 'addr', 'add', addr, 'dev', nic]
     ip_link_cmd = ['ip', 'link', 'set', 'dev', nic, 'up']
 
-    if not util.which('ip'):
+    if not subp.which('ip'):
         raise RuntimeError("No 'ip' command available to configure ip4LL "
                            "address")
 
     try:
-        util.subp(ip_addr_cmd)
+        subp.subp(ip_addr_cmd)
         LOG.debug("assigned ip4LL address '%s' to '%s'", addr, nic)
-        util.subp(ip_link_cmd)
+        subp.subp(ip_link_cmd)
         LOG.debug("brought device '%s' up", nic)
     except Exception:
         util.logexc(LOG, "ip4LL address assignment of '%s' to '%s' failed."
@@ -74,7 +75,7 @@ def del_ipv4_link_local(nic=None):
     ip_addr_cmd = ['ip', 'addr', 'flush', 'dev', nic]
 
     try:
-        util.subp(ip_addr_cmd)
+        subp.subp(ip_addr_cmd)
         LOG.debug("removed ip4LL addresses from %s", nic)
 
     except Exception as e: