ansible/examples/playbooks/register_logic.yml

29 lines
1.4 KiB
YAML

# here's a cool advanced topic about how to perform conditional logic in ansible without resorting
# to writing your own module that defines facts. You can do that too, and it's easy to do, but
# often you just want to run a command and then decide whether to run some steps or not. That's
# easy to do, and here we'll show you how.
- name: test playbook
user: root
hosts: all
tasks:
# it is possible to save the result of any command in a named register. This variable will be made
# available to tasks and templates made further down in the execution flow. Here we save the result
# of a simple 'cat' command in a variable called 'motd_contents'
- action: shell cat /etc/motd
register: motd_contents
# and here we access the register. Note that motd_contents as a variable is structured data because
# it is a return from the command module. The shell module makes available variables such as
# as 'stdout', 'stderr', and 'rc'. Here's a rather trivial example that runs an arbitrary step
# if and only if the motd file contained the word 'hi'. Remember that only_if statements are
# Python expressions. This is as complicated as Ansible syntax is going to get, and the only
# time python really seeps into ansible's language.
- action: shell echo "motd contains the word hi"
only_if: "'${motd_contents.stdout}'.find('hi') != -1"