Question 245573 in Debian Question posted in
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Debian – use a for in a variable in host_vars/group_vars

I want to minimize my efforts when adding content to my hosts/vars groups.

For example, I have a variable that looks like this:

blue_items:

- name: ocean
  color: blue
- name: sky
  color: blue
- name: umbrella
  color: blue

result with a debug:

root@debian:/opt/ansible# ansible -m "debug msg="{{blue_items}}"" client1 client1 | SUCCESS => {     "msg": [         {             "color": "blue",             "name": "ocean"         },         {             "color": "blue",             "name": "sky"         },         {             "color": "blue",             "name": "umbrella"         }     ] }

I tried to use a "for" parsing into a list:

my host_vars:

list_blue_items: ['ocean', 'sky', 'umbrella']

blue_items:
{% for item in list_blue_items %}

- name: "{{ item }}"
  color: blue
  {% endfor %}

result with a debug:

ERROR! We were unable to read either as JSON nor YAML, these are the errors we got from each:
JSON: Expecting value: line 1 column 1 (char 0)

Syntax Error while loading YAML.
found character that cannot start any token

The error appears to be in '/opt/ansible/host_vars/client1/nginx.yml': line 4, column 2, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

blue_items:
{% for item in list_blue_items %}
^ here

I also tried adding a pipe in front of the variable like this :

list_blue_items: ['ocean', 'sky', 'umbrella']

blue_items: |
{% for item in list_blue_items %}

- name: "{{ item }}"
  color: blue
  {% endfor %}

But the result isn’t like i want, all the content is written on a single line and don’t return my items:

client1 | SUCCESS => {     "msg": "- name: "ocean"n  color: bluen- name: "sky"n  color: bluen- name: "umbrella"n  color: bluen" }
Tags:

3

Answers


  1. Chosen as BEST ANSWER
    0

    Thank you for your answer :)

    I tried your first solution but it doesn't seem to work :'(

    I have a more complex exemple:

    In my host_vars file:

    nginx__vhost:
  - name: vhost1.test.com
    file_conf: vhost1.test.com.conf
    name: option1, option2
    tls: /etc/letsencrypt/live/vhost1.test.com.key

  - name: vhost2.test.com
    file_conf: vhost2.test.com.conf
    name: option1, option2
    tls: /etc/letsencrypt/live/vhost2.test.com.key

    output:

    client1 | SUCCESS => {
    "msg": [
        {
            "file_conf": "vhost1.test.com.conf",
            "name": "option1, option2",
            "tls": "/etc/letsencrypt/live/vhost1.test.com.key"
        },
        {
            "file_conf": "vhost2.test.com.conf",
            "name": "option1, option2",
            "tls": "/etc/letsencrypt/live/vhost2.test.com.key"
        }
    ]
}

    I need to manipulate all of these data like "nginx__vhost.name, nginx__vhost.tls, nginx__vhost.file_conf" and a lot of other...

    I also tried to use "{% filter from_yaml %}"

    nginx__vhost_list: ['vhost1.test.com', 'vhost2.test.com']

nginx__vhost: |
  {% filter from_yaml %}
  {% for vhost in nginx__vhost_list %}
  - {name: "{{vhost}}"
    file_conf: "{{vhost}}.conf"
    name: option1, option2
    tls: "/etc/letsencrypt/live/{{vhost}}.key"}
  {% endfor %}
  {% endfilter %}

    but it provides me an error

    client1 | FAILED! => {
    "msg": "An unhandled exception occurred while templating '{% filter from_yaml %}n{% for vhost in nginx__vhost_list %}n- {name: "{{vhost}}"n  file_conf: "{{vhost}}.conf"n  name: option1, option2n  tls: "/etc/letsencrypt/live/{{vhost}}.key"}n{% endfor %}n{% endfilter %}n'. Error was a <class 'yaml.parser.ParserError'>, original message: while parsing a flow mappingn  in "<unicode string>", line 1, column 3:n    - {name: "vhost1.test.com"n      ^nexpected ',' or '}', but got '<scalar>'n  in "<unicode string>", line 2, column 3:n      file_conf: "vhost1.test.com.conf"n      ^"
}

    I think i have to use the "from_yaml" functionnality but idk why the "{% filter from_yaml %}" doesn't work :/


  2. 0

    For example, given the data in group_vars

    shell> cat group_vars/all/colors.yml
data:
  blue: [ocean, sky, umbrella]
  green: [grass, peas, car]
  red: [flag, apple, hat]
    • Use Jinja if you want the for loop
    blue_items: |
  {% filter from_yaml %}
  {% for i in data.blue %}
  - {name: {{ i }}, color: blue}
  {% endfor %}
  {% endfilter %}

    gives what you want

    blue_items:
  - color: blue
    name: ocean
  - color: blue
    name: sky
  - color: blue
    name: umbrella
    • Optionally, you can use the filter product and create a dictionary first
    blue_items: "{{ dict(data.blue|product(['blue'])) }}"

    gives

    blue_items:
  ocean: blue
  sky: blue
  umbrella: blue

    If you need the list of the dictionaries use the filter dict2items

    blue_items: "{{ dict(data.blue|product(['blue']))|
                dict2items(key_name='name', value_name='color') }}"

    also gives what you want

    blue_items:
  - color: blue
    name: ocean
  - color: blue
    name: sky
  - color: blue
    name: umbrella

    Example of a complete project for testing

    shell> cat group_vars/all/colors.yml
data:
  blue: [ocean, sky, umbrella]
  green: [grass, peas, car]
  red: [flag, apple, hat]

blue_items: "{{ dict(data.blue|product(['blue'])) }}"

blue_item2: "{{ dict(data.blue|product(['blue']))|
                dict2items(key_name='name', value_name='color') }}"

blue_item3: |
  {% filter from_yaml %}
  {% for i in data.blue %}
  - {name: {{ i }}, color: blue}
  {% endfor %}
  {% endfilter %}

    shell> cat pb.yml
- hosts: all

  tasks:

    - debug:
        var: blue_items
    - debug:
        var: blue_item2
    - debug:
        var: blue_item3

    There are plenty of other options on how to use the data. For example, declare color_items

    color_items: "{{ dict(data[color]|product([color])) }}"

    and use it in the tasks

        - debug:
        var: color_items
      vars:
        color: blue

    gives

      color_items:
    ocean: blue
    sky: blue
    umbrella: blue

    Use the dictionary in a loop

        - debug:
        msg: "{{ item }}"
      loop: "{{ color_items|dict2items }}"
      vars:
        color: blue

    gives

    ok: [host_A] => (item={'key': 'ocean', 'value': 'blue'}) => 
  msg:
    key: ocean
    value: blue
ok: [host_A] => (item={'key': 'sky', 'value': 'blue'}) => 
  msg:
    key: sky
    value: blue
ok: [host_A] => (item={'key': 'umbrella', 'value': 'blue'}) => 
  msg:
    key: umbrella
    value: blue

    If you use item in the declaration instead of color

    color_items: "{{ dict(data[item]|product([item])) }}"

    you can iterate the colors

        - debug:
        msg: "{{ color_items }}"
      loop: "{{ data.keys() }}"

    gives

    ok: [host_A] => (item=blue) => 
  msg:
    ocean: blue
    sky: blue
    umbrella: blue
ok: [host_A] => (item=green) => 
  msg:
    car: green
    grass: green
    peas: green
ok: [host_A] => (item=red) => 
  msg:
    apple: red
    flag: red
    hat: red
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  3. 0

    I finally succeeded in creating a new variable:

    nginx__vhost_list:
  - vhost1.test.com
  - vhost2.test.com

nginx__vhost: |
  {% for vhost in nginx__vhost_list %}
  - name: "{{ vhost }}"
    file_conf: "{{ vhost }}.conf"
    name: option1, option2
    tls: "/etc/letsencrypt/live/{{ vhost }}.key"
  {% endfor %}

nginx__vhost_final:
  "{{ nginx__vhost | from_yaml }}"

    Wouldn’t it be possible to keep only my "nginx__vhost" list, I don’t think it’s a good way to create a variable just to filter another one, I’d rather be able to filter directly on the 1st variable.

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