Add support for application version

Juju 2.0 provides support for display of the version of
an application deployed by a charm in juju status.

Insert the os_application_version_set function into the
existing assess_status function - this gets called after
all hook executions, and periodically after that, so any
changes in package versions due to normal system updates
will also be reflected in the status output.

This review also includes a resync of charm-helpers to
pickup hookenv and contrib.openstack support for this
feature.

Change-Id: I059d03fd0ae0c445b5822b3e48476e54b839689d

charmhelpers/core/host.py

@@ -30,13 +30,29 @@ import subprocess
 import hashlib
 import functools
 import itertools
-from contextlib import contextmanager
-from collections import OrderedDict
-
 import six
 
+from contextlib import contextmanager
+from collections import OrderedDict
 from .hookenv import log
 from .fstab import Fstab
+from charmhelpers.osplatform import get_platform
+
+__platform__ = get_platform()
+if __platform__ == "ubuntu":
+    from charmhelpers.core.host_factory.ubuntu import (
+        service_available,
+        add_new_group,
+        lsb_release,
+        cmp_pkgrevno,
+    )  # flake8: noqa -- ignore F401 for this import
+elif __platform__ == "centos":
+    from charmhelpers.core.host_factory.centos import (
+        service_available,
+        add_new_group,
+        lsb_release,
+        cmp_pkgrevno,
+    )  # flake8: noqa -- ignore F401 for this import
 
 
 def service_start(service_name):
@@ -144,8 +160,11 @@ def service_running(service_name):
                 return False
             else:
                 # This works for upstart scripts where the 'service' command
-                # returns a consistent string to represent running 'start/running'
-                if "start/running" in output:
+                # returns a consistent string to represent running
+                # 'start/running'
+                if ("start/running" in output or
+                        "is running" in output or
+                        "up and running" in output):
                     return True
         elif os.path.exists(_INIT_D_CONF.format(service_name)):
             # Check System V scripts init script return codes
@@ -153,18 +172,6 @@ def service_running(service_name):
         return False
 
 
-def service_available(service_name):
-    """Determine whether a system service is available"""
-    try:
-        subprocess.check_output(
-            ['service', service_name, 'status'],
-            stderr=subprocess.STDOUT).decode('UTF-8')
-    except subprocess.CalledProcessError as e:
-        return b'unrecognized service' not in e.output
-    else:
-        return True
-
-
 SYSTEMD_SYSTEM = '/run/systemd/system'
 
 
@@ -173,8 +180,9 @@ def init_is_systemd():
     return os.path.isdir(SYSTEMD_SYSTEM)
 
 
-def adduser(username, password=None, shell='/bin/bash', system_user=False,
-            primary_group=None, secondary_groups=None, uid=None, home_dir=None):
+def adduser(username, password=None, shell='/bin/bash',
+            system_user=False, primary_group=None,
+            secondary_groups=None, uid=None, home_dir=None):
     """Add a user to the system.
 
     Will log but otherwise succeed if the user already exists.
@@ -286,17 +294,7 @@ def add_group(group_name, system_group=False, gid=None):
             log('group with gid {0} already exists!'.format(gid))
     except KeyError:
         log('creating group {0}'.format(group_name))
-        cmd = ['addgroup']
-        if gid:
-            cmd.extend(['--gid', str(gid)])
-        if system_group:
-            cmd.append('--system')
-        else:
-            cmd.extend([
-                '--group',
-            ])
-        cmd.append(group_name)
-        subprocess.check_call(cmd)
+        add_new_group(group_name, system_group, gid)
         group_info = grp.getgrnam(group_name)
     return group_info
 
@@ -541,16 +539,6 @@ def restart_on_change_helper(lambda_f, restart_map, stopstart=False,
     return r
 
 
-def lsb_release():
-    """Return /etc/lsb-release in a dict"""
-    d = {}
-    with open('/etc/lsb-release', 'r') as lsb:
-        for l in lsb:
-            k, v = l.split('=')
-            d[k.strip()] = v.strip()
-    return d
-
-
 def pwgen(length=None):
     """Generate a random pasword."""
     if length is None:
@@ -674,25 +662,6 @@ def get_nic_hwaddr(nic):
     return hwaddr
 
 
-def cmp_pkgrevno(package, revno, pkgcache=None):
-    """Compare supplied revno with the revno of the installed package
-
-    *  1 => Installed revno is greater than supplied arg
-    *  0 => Installed revno is the same as supplied arg
-    * -1 => Installed revno is less than supplied arg
-
-    This function imports apt_cache function from charmhelpers.fetch if
-    the pkgcache argument is None. Be sure to add charmhelpers.fetch if
-    you call this function, or pass an apt_pkg.Cache() instance.
-    """
-    import apt_pkg
-    if not pkgcache:
-        from charmhelpers.fetch import apt_cache
-        pkgcache = apt_cache()
-    pkg = pkgcache[package]
-    return apt_pkg.version_compare(pkg.current_ver.ver_str, revno)
-
-
 @contextmanager
 def chdir(directory):
     """Change the current working directory to a different directory for a code