looping a shell command in ansible - ansible

Question

I'm trying to get going with some more advanced Ansible playbooks and have hit a wall. I'm trying to get Ansible to do what this /bin/bash 'for' loop does;
for i in $(</filename.txt);do '/some/command options=1 user=usera server=$i';done
filesnames.txt contains 50-100 hostnames.
I can't use jinja templates as the command has to be run, not just the config file updated.
Any help would be greatly appreciated.
Thanks in advance,
Jeremy

Answer 1

you can use jinja templates, but differently
your specific code is not doing something that is most advisable
for multi-line code you should use shell module.
example of multi-code piece of call:
- name: run multiline stuff
shell: |
for x in "${envvar}"; do
echo "${x}"
done
args:
executable: /bin/bash
note I'm explicitly setting executable, which will ensure bash-isms would work.
I just used envvar as an example, of arbitrary environment variable available.
if you need to pass specific env variables, you should use environment clause of the call to shell module, refer to: http://docs.ansible.com/ansible/playbooks_environment.html
For simple variables you can just use their value in shell: echo "myvar: {{myvar}}"
If you wish to use an ansible list/tuple variable inside bash code, you can make it bash variable first. e.g. if you have a list of stuff in mylist, you can expand it and assign into a bash array, and then iterate over it. the shell code of the call to shell would be:
mylist_for_bash=({{mylist|join(" ")}})
for myitem in "${mylist_for_bash[#]}"; do
echo "my current item: ${myitem}"
done
Another approach would be to pass it as string env variable, and convert it into an array later in the code.
NOTE:
of course all this works correctly only with SPACELESS values
I've never had to pass array with space containing items