Enable counter_enabled.py to support batch mode (#3709) (#3731)

* Enable counter_enabled.py to support serial mode

Enable counter_enabled.py to support batch playbook executions using the serial tag in plays. Currently, the host counter gets reset at the beginning of every task. However, during batch executions we want it to keep track of the previous batch executions and print the host counter based on the previous runs. This proposal keeps track of how many servers have been updated in previous batches and starts the host counter at that tracked value.

```
- hosts: allthethings
  gather_facts: no
  serial:
    - 3
    - 15%
    - 20%
    - 35%
    - 55%
    - 90%
    - 100%
  tasks:
    - name: Ping Hello!
      ping:
        data: "Hello!!!!"
```

* Reset task counter on play start

Reset task counter on play start for batch mode playbook executions.

* Add changelog fragment

* change changelog fragment after feedback

Co-authored-by: Felix Fontein <felix@fontein.de>

Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit f5b4dcc564)

Co-authored-by: Nabheet Sandhu <nabheet@users.noreply.github.com>

changelogs/fragments/3709-support-batch-mode.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - counter_enabled callback plugin - fix output to correctly display host and task counters in serial mode (https://github.com/ansible-collections/community.general/pull/3709).

plugins/callback/counter_enabled.py

@@ -45,6 +45,8 @@ class CallbackModule(CallbackBase):
     _task_total = 0
     _host_counter = 1
     _host_total = 0
+    _current_batch_total = 0
+    _previous_batch_total = 0
 
     def __init__(self):
         super(CallbackModule, self).__init__()
@@ -76,8 +78,11 @@ class CallbackModule(CallbackBase):
         self._display.banner(msg)
         self._play = play
 
+        self._previous_batch_total = self._current_batch_total
+        self._current_batch_total = self._previous_batch_total + len(self._all_vars()['vars']['ansible_play_batch'])
         self._host_total = len(self._all_vars()['vars']['ansible_play_hosts_all'])
         self._task_total = len(self._play.get_tasks()[0])
+        self._task_counter = 1
 
     def v2_playbook_on_stats(self, stats):
         self._display.banner("PLAY RECAP")
@@ -145,7 +150,7 @@ class CallbackModule(CallbackBase):
             path = task.get_path()
             if path:
                 self._display.display("task path: %s" % path, color=C.COLOR_DEBUG)
-        self._host_counter = 0
+        self._host_counter = self._previous_batch_total
         self._task_counter += 1
 
     def v2_runner_on_ok(self, result):