emit the cloud-config event again

The merge of 0.7.0 dropped the cloud-config initctl emission.
I've added it back here, but done so in a way that doesn't force
non-ubuntu (or non-upstart) distros to provide this config setting
to disable it.

bin/cloud-init

@@ -100,6 +100,29 @@ def welcome_format(action):
     return templater.render_string(WELCOME_MSG_TPL, tpl_params)
 
 
+def emit_cloud_config_ready(cfg, cfgpath):
+    # emit the cloud config ready event
+    # this can be used by upstart jobs for 'start on cloud-config'. There is a
+    # builtin value for 'cc_ready_cmd' if that is not overidden by config, then
+    # we check to make sure that /sbin/initctl is availble.  This makes it so
+    # that non-ubuntu distro will just no-op here with no explicit config.
+    cmd = None
+    if 'cc_ready_cmd' in cfg:
+        cmd = cfg['cc_ready_cmd']
+        if isinstance(cmd, str):
+            cmd = ['sh', '-c', cmd]
+    elif os.path.isfile("/sbin/initctl"):
+        cmd = ['initctl', 'emit', 'cloud-config',
+               'CLOUD_CFG=%s' % cfgpath]
+
+    if not cmd:
+        return
+    try:
+        util.subp(cmd)
+    except:
+        LOG.warn("emission of cloud-config event failed")
+
+
 def extract_fns(args):
     # Files are already opened so lets just pass that along
     # since it would of broke if it couldn't have
@@ -338,6 +361,11 @@ def main_modules(action_name, args):
     # now that logging is setup and stdout redirected, send welcome
     welcome(name, msg=w_msg)
 
+    # send the cloud-config event.
+    if name == "config":
+        emit_cloud_config_ready(mods.cfg,
+            init.paths.get_ipath_cur("cloud_config"))
+
     # Stage 5
     return run_module_section(mods, name, name)