Avoid traceback when using ansible >=2.4

Starting from ansible 2.4 command line options are now received as a
list. In ansible >=2.4 it's now technically possible to specify multiple
times the '-i' option (even if the documentation say otherwise).

This commit merge all host while removing any extra comas.

Author: hush-hush

CHANGELOG.md

@@ -1,11 +1,15 @@
 CHANGELOG
 =========
 
+# 1.0.2 / 2017-12-11
+* [BUGFIX] Avoid failure when using ansible 2.4. See [#27][]
+
 # 1.0.1 / 2016-06-06
 * [BUGFIX] Avoid failure when `res['invocation']` has no `module_name` key. See [#19][]
 
 # 1.0.0 / 2016-06-02
 First release, compatible with Ansible v1 & v2
 
 <!--- The following link definition list is generated by PimpMyChangelog --->
+[#27]: https://github.com/DataDog/ansible-datadog-callback/issues/27
 [#19]: https://github.com/DataDog/ansible-datadog-callback/issues/19

datadog_callback.py

@@ -122,7 +122,11 @@ def _handle_playbook_on_start(self, playbook_file_name, inventory):
         # Set the playbook name from its filename
         self._playbook_name, _ = os.path.splitext(
             os.path.basename(playbook_file_name))
-        inventory_name = os.path.basename(os.path.realpath(inventory))
+
+        # inventory is a comma separated host list: ["host1,host2","host3,host4,"]
+        if isinstance(inventory, basestring):
+            inventory = inventory.split(',')
+        inventory_name = ','.join([os.path.basename(os.path.realpath(name)) for name in inventory if name])
 
         self.send_playbook_event(
             'Ansible playbook "{0}" started by "{1}" against "{2}"'.format(