in 2.0.1.0 and later, skipped plays impact gathering=smart

[larsks]

ISSUE TYPE

• Bug Report

ANSIBLE VERSION

ansible 2.0.1.0
  config file = 
  configured module search path = Default w/o overrides

CONFIGURATION

N/A

OS / ENVIRONMENT

N/A

SUMMARY

When ANSIBLE_GATHERING is smart, a skipped play targeting a
particular host will cause Ansible to not collect facts for that host.

STEPS TO REPRODUCE

Use this playbook:

- hosts: localhost
  tags:
    - sampletag
  tasks:
    - debug:
        msg: "this play can be skipped with --skip-tags sampletag"

- hosts: localhost
  tasks:
    - assert:
        that: ansible_distribution is defined

Compare:

ANSIBLE_GATHERING=implicit ansible-playbook playbook.yml \
  --skip-tags sampletag

With:

ANSIBLE_GATHERING=smart ansible-playbook playbook.yml \
  --skip-tags sampletag

In version 2.0.0.0, you will see:

PLAY ***************************************************************************

TASK [setup] *******************************************************************
ok: [localhost]

PLAY ***************************************************************************

TASK [assert] ******************************************************************
ok: [localhost]

PLAY RECAP *********************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0   

But in version 2.0.1.0 and 2.0.2.0 you will see:

PLAY ***************************************************************************

PLAY ***************************************************************************

TASK [assert] ******************************************************************
fatal: [localhost]: FAILED! => {"assertion": "ansible_distribution is defined", "changed": false, "evaluated_to": false, "failed": true}

NO MORE HOSTS LEFT *************************************************************
        to retry, use: --limit @playbook.retry

PLAY RECAP *********************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=1   

That is, a play that is completely skipped and produces no output
during the ansible-playbook and does not run the setup module
still results in Ansible not running setup in subsequent tasks.

EXPECTED RESULTS

I expect Ansible to connect to the target host and gather facts at
least once during the play.

ACTUAL RESULTS

No facts are gathered.

[larsks]

@jimi-c This appears to have been introduced by 5587b08.

[larsks]

I think the solution is to not set gathered_facts=True in _get_next_task_from_state unless there are tasks to be executed. For devel, I think that means:

diff --git a/lib/ansible/executor/play_iterator.py b/lib/ansible/executor/play_iterator.py
index 3ab2e28..b5fc8bf 100644
--- a/lib/ansible/executor/play_iterator.py
+++ b/lib/ansible/executor/play_iterator.py
@@ -295,10 +295,10 @@ class PlayIterator:
                         setup_block = self._blocks[0]
                         if setup_block.has_tasks() and len(setup_block.block) > 0:
                             task = setup_block.block[0]
-                        if not peek:
-                            # mark the host as having gathered facts, because we're
-                            # returning the setup task to be executed
-                            host.set_gathered_facts(True)
+                            if not peek:
+                                # mark the host as having gathered facts, because we're
+                                # returning the setup task to be executed
+                                host.set_gathered_facts(True)
                 else:
                     # This is the second trip through ITERATING_SETUP, so we clear
                     # the flag and move onto the next block in the list while setting

And for 2.0.1.0 I think that means:

diff --git a/lib/ansible/executor/play_iterator.py b/lib/ansible/executor/play_iterator.py
index 1826432..1382133 100644
--- a/lib/ansible/executor/play_iterator.py
+++ b/lib/ansible/executor/play_iterator.py
@@ -255,9 +255,9 @@ class PlayIterator:
                        (gathering == 'explicit' and boolean(self._play.gather_facts)) or \
                        (gathering == 'smart' and implied and not host._gathered_facts):
                         # mark the host as having gathered facts
-                        host.set_gathered_facts(True)
                         setup_block = self._blocks[0]
                         if setup_block.has_tasks() and len(setup_block.block) > 0:
+                            host.set_gathered_facts(True)
                             task = setup_block.block[0]
                 else:
                     state.pending_setup = False

These changes seem to result in the appropriate behavior.

[larsks]

With the above patch in place, running the above reproducer correctly results in:

PLAY [localhost] ***************************************************************

PLAY [localhost] ***************************************************************

TASK [setup] *******************************************************************
ok: [localhost]

TASK [assert] ******************************************************************
ok: [localhost]

PLAY RECAP *********************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0   

[jimi-c]

Closing This Ticket

Hi!

We believe the above commit should resolve this problem for you. This will also be included in the next release.

If you continue seeing any problems related to this issue, or if you have any further questions, please let us know by stopping by one of the two mailing lists, as appropriate:

• https://groups.google.com/forum/#!forum/ansible-project - for user questions, tips, and tricks
• https://groups.google.com/forum/#!forum/ansible-devel - for strategy, future planning, and questions about writing code

Because this project is very active, we're unlikely to see comments made on closed tickets, but the mailing list is a great way to ask questions, or post if you don't think this particular issue is resolved.

Thank you!