Ansible with_subelements default value

Question

i have a vars definition like this: ``` sites: - site: mysite1.com exec_init: - "command1 to exec" - "command2 to exec" - site: mysite2.com ``` then i have play with the following task ``` - name: Execute init scripts for all sites shell: "{{item.1}}" with_subelements: - sites - exec_init when: item.0.exec_init is defined ``` The idea here is that i will have multiple "Site" definitions with dozens of other properties in my vars, then i would like to execute multiple Shell script commands for those sites having "exec_init" defined Doing it this way it just always skip executing the task, i've tried this in all combinations i can imagine but i just can't get it to work... Is this the proper way of doing it? maybe i'm trying to achieve something that doesn't make sense? Thanks for your help

Accepted Answer

Hm, looks like having a non-uniform structure for the elements in `sites` is something `with_subelements` doesn't like. And also that `item` doesn't contain the subelement you specified in the with_subelements list. You can do several things:

Make sure to have an `exec_init` list, even if it's empty. `with_subelements` will skip items with empty subelements. I think this is the best option, although a bit inconvenient when writing the playbook.

Don't use `with_subelements` and batch execute yourself (a bit ugly):

```
- name: Execute init scripts for all sites
  shell: "echo '{{item.exec_init | join(';')}}' | bash"
  when: item.exec_init is defined
  with_items: sites
```

Customize `with_subelements` so that it would items with the missing subelement. You can copy the original (mine is in `/usr/local/lib/python2.7/dist-packages/ansible/runner/lookup_plugins/with_subelements.py`) and put it in a `lookup_plugins` directory next to your playbook, under a different name (say `subelements_missingok.py`). Then change line 59 from:

```
raise errors.AnsibleError("could not find '%s' key in iterated item '%s'" % (subelement, item0))
```

to:

```
continue
```

Then your task can look like this:

```
- name: Execute init scripts for all sites
  debug: "msg={{item.1}}"
  with_subelements_missingok:
    - sites
    - exec_init
```

Ansible with_subelements default value

Solution

Problem