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Dax
Asked: 2017-11-06 01:37:36 +0800 CST

How can I set a fact based on a file's existence using a param for filename?

  • 772

This is what I came up with for a single host

- name: Check for Let's Encrypt certificate
  block:
    - name: Set default for variable
      set_fact:
        use_letsencrypt: false

    - name: Get stat for cert file
      stat:
        path: /etc/letsencrypt/live/{{ hostname }}/cert.pem
      register: certificate_file

    - name: Set letsencrypt to true if certificate exists
      set_fact:
        use_letsencrypt: true
      when: certificate_file.stat.exists

How can I make this more DRY? Pass it a hostname and it returns a true or false for the variable.

Edit: More info to make it more clear. It already works fine as is.

I want to use the above snippet for more than one host across different playbooks without copy and pasting the snippet every time.

I use the variable use_letsencrypt in different mail and web configuration files and would like to say, I'm busy setting up a config for example.com, do I have a cert for it.

ansible

2 Answers

  1. Best Answer

    OK. So playing around and reading some more docs, I found the answer.

    You can put the above snippet in its own role and just include it every time you need it.

    - name: Set use_letsencrypt
  include_role:
    name: has_letsencrypt
  vars:
    hostname: example.com

    So it acts like a module and you just pass it a var. I can use that snippet multiple times across different playbooks now.

    • 3

  2. I'm not sure if I understand you right.

    I expect that the posted code is just a snipped of complete playbook.

    In order to pass the variable just temporarily, you can use -e parameter of ansible-playbook:

      -e EXTRA_VARS, --extra-vars=EXTRA_VARS
                        set additional variables as key=value or 
                        YAML/JSON, if filename prepend with @

    So you'd run ansible-playbook like:

    ansible-playbook -e "hostname=YourHostname" your.yaml

    And if you don't want to run on all nodes specified in the playbook/role, you can limit it from the command line too. Use parameter -l:

      -l SUBSET, --limit=SUBSET
                        further limit selected hosts to an additional 
                        pattern

    The command would be then:

    ansible-playbook -e "hostname=YourHostname" -l YourHostname your.yaml

    If you want ansible to get local hosname, it's available via setup module. Tray to use {{ ansible_hostname }} instead of your {{ hostname }}.

    If you want to see complete list of variables provided by setup module, just run:

    ansible -m setup <your host>
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