Executive summary: skipping a host corrupts a variable (when it is registered)
We have a play existing out of multiple tasks that check a condition, if one of these tasks fails we want to skip all next tasks in the playbook. I noticed that if we skip a task because a certain condition is met, and this task has a register-attribute, I loose the value in the variable. Which means we cannot use that variable in subsequent tasks to evaluate because it was skipped:
```
- action: command test -d /some/directory
register: task
- action: command test -f /some/directory/file
register: task
only_if: '${task.rc} == 0'
- action: do something else
only_if: '${task.rc} == 0'
```
In the above example, if the second task is skipped (because the first failed), the third action will end with a "SyntaxError: invalid syntax" complaining about the unsubstituted ${task.rc} (even though it was set by the first task and used for skipping the second).
The following play demonstrates the problem:
```
- name: Test register on ignored tasks
hosts: all
gather_facts: no
vars:
skip: true
task: { 'rc': 666 }
tasks:
- action: debug msg='skip = ${skip}, task.rc = ${task.rc}'
- name: Skip this task, just to test if task has changed
action: command ls
register: task
only_if: '${skip} != True'
- action: debug msg='skip = ${skip}, task.rc = ${task.rc}'
- name: Now use task value
action: command echo 'Works !'
only_if: '${task.rc} == 0'
```
And the enclosed fix, fixes the above problem.
We now check explicitely for 'module_setup' in the SETUP_CACHE in order to avoid skipping setup because SETUP_CACHE was populated some other way. Other modules can implement the same mechanism to test if they've already run.
This closes#1206.
This change makes a distinction between no_hosts_matched and no_hosts_remaining.
In both cases we do not start facts-gathering, or run any tasks.
In the case that there are no more hosts remaining, we abort running tasks and abort the playbook.
I also cleaned up the leftovers from the previous patchsets, as these are no longer required.
This closes#1187.
Example playbook:
```yaml
---
- hosts: emptygroup
tasks:
- action: command date
- action: command false
- hosts: all
gather_facts: False
tasks:
- action: command ls
- action: command false
- action: command true
- hosts: all
tasks:
- action: command true
- action: command false
- hosts: all
tasks:
- action: command pwd
```
When the output of a command is stored in a register, this will create a
stdout_lines field in the result object that contains stdout split into a list
of lines. This list can then be iterated over using with_items.
Previously, importing a playbook in a different directory didn't
work because all of the relative paths were resolved relative to
the top-level playbook.
This patch resolves relative paths on a per-play level instead of
relative to the directory of the top-level playbook.
Also removes the dirname argument from the Play._get_vars method
since this argument wasn't used in the metho dbody.
The default is 0, which means all hosts. If set to 1, each host would run a playbook all the way through before moving
on the next host. Fact gathering is still parallel, regardless of the serial setting.
to an additional pattern (a subset) specified on the command line. For instance, a playbook could be reusable
and target "webservers" and "dbservers", but you want to test only in the stage environment, or a few boxes at a time.
Daniel Hokka Zakrisson
Michael DeHaan
Dag Wieers
Aurélien Bondis
John Kleint
Lorin Hochstein
Mark Theunissen
Dave Peticolas
Dave Peticolas
Jeroen Hoekx