Warn if no hosts matched

lib/ansible/callbacks.py

@@ -95,6 +95,9 @@ class DefaultRunnerCallbacks(object):
     def on_unreachable(self, host, res):
         pass
 
+    def on_no_hosts(self):
+        pass
+
 ########################################################################
 
 class CliRunnerCallbacks(DefaultRunnerCallbacks):
@@ -120,6 +123,9 @@ class CliRunnerCallbacks(DefaultRunnerCallbacks):
 
     def on_error(self, host, err):
         print >>sys.stderr, "stderr: [%s] => %s\n" % (host, err)
+    
+    def on_no_hosts(self):
+        print >>sys.stderr, "no hosts matched\n"
 
     def _on_any(self, host, result):
         print utils.host_report_msg(host, self.options.module_name, result, self.options.one_line)
@@ -159,6 +165,9 @@ class PlaybookRunnerCallbacks(DefaultRunnerCallbacks):
     def on_skipped(self, host):
         print "skipping: [%s]\n" % host
 
+    def on_no_hosts(self):
+        print "no hosts matched or remaining\n"
+
 ########################################################################
 
 class PlaybookCallbacks(object):

lib/ansible/runner.py

@@ -750,6 +750,7 @@ class Runner(object):
         # find hosts that match the pattern
         hosts = self._match_hosts(self.pattern)
         if len(hosts) == 0:
+            self.callbacks.on_no_hosts()
             return dict(contacted={}, dark={})
  
         hosts = [ (self,x) for x in hosts ]

test/TestPlayBook.py

@@ -89,6 +89,8 @@ class TestCallbacks(object):
     def on_setup_secondary(self):
         pass
 
+    def on_no_hosts(self):
+        pass
 
 class TestPlaybook(unittest.TestCase):