How to check if list of strings are present in command output in Ansible?

Question

I want to run an Ansible action on the condition that a shell command doesn't return the expected output. ogr2ogr --formats pretty-prints a list of compatible file formats. I want to grep the formats output, and if my expected file formats aren't in the output, I want to run a command to install these components. Does anyone know how to do this?

- name: check if proper ogr formats set up   command: ogr2ogr --formats | grep $item   with_items:     - PostgreSQL     - FileGDB     - Spatialite   register: ogr_check  # If grep from ogr_check didn't find a certain format from with_items, run this - name: install proper ogr formats   action: DO STUFF   when: Not sure what to do here 

Answer 1

First, please make sure you are using Ansible 1.3 or later. Ansible is still changing pretty quickly from what I can see, and a lot of awesome features and bug fixes are crucial.

As for checking, you can try something like this, taking advantage of grep's exit code:

- name: check if proper ogr formats set up   shell: ogr2ogr --formats | grep $item   with_items:     - PostgreSQL     - FileGDB     - Spatialite   register: ogr_check   # grep will exit with 1 when no results found.    # This causes the task not to halt play.   ignore_errors: true  - name: install proper ogr formats   action: DO STUFF   when: ogr_check|failed 

There are some other useful register variables, namely item.stdout_lines. If you'd like to see what's registered to the variable in detail, try the following task:

- debug: msg={{ogr_check}} 

and then run the task in double verbose mode via ansible-playbook my-playbook.yml -vv. It will spit out a lot of useful dictionary values.