在Jinja2中重写群组模板

Question

I have a few templates where I need to decorate some server names and I'd like to do this in one line so that I can use the string as a variable.

{{ group_vars["dbservers"] | WHAT GOES HERE | list }}

that will take a list like

[dbservers]
db-1
db-2
db-3

and then in the template I need them like this:

{
  servers: [
    "http://db-1:1234", 
    "http://db-2:1234", 
    "http://db-3:1234"
  ] ....
}

As of now I am doing something like this:

servers: [
{% for h in groups["dbservers"] %}
"http://{{hostvars[h].ansible_fqdn}}:{{ mymagicport}}"
{% if not loop.last %},{% endfor %}
{% endfor %}
]

which I don't love at all. I'd like to be able to store this in a usable way and then just call config.to_nice_json

But I can't seem to find the right recipe to inline the value. I have been messing around with the map function but to no avail. Any ideas?

Answer 1

It is doable with map and regex_replace :

hosts :

[db-servers]
db-1 fqdn_fact=db-server-1
db-2 fqdn_fact=db-srv-2
db-3 fqdn_fact=server-3

playbook :

---
- hosts: localhost
  gather_facts: no
  vars:
    mymagicport: '1234'
  tasks:
    - debug:
        msg: "{{ groups['db-servers'] | map('regex_replace','(.*)','http://\\1:'+mymagicport) | list }}"
    - debug:
        msg: "{{ groups['db-servers'] | map('extract',hostvars,'fqdn_fact') | map('regex_replace','(.*)','http://\\1:'+mymagicport) | list }}"

First task – to work with inventory hostnames, second task – to work with arbitrary fact from hostvars .

result:

TASK [debug] *******************************************************************
ok: [localhost] => {
    "msg": [
        "http://db-1:1234",
        "http://db-2:1234",
        "http://db-3:1234"
    ]
}

TASK [debug] *******************************************************************
ok: [localhost] => {
    "msg": [
        "http://db-server-1:1234",
        "http://db-srv-2:1234",
        "http://server-3:1234"
    ]
}