Say I have this dictionary
war_files:
server1:
- file1.war
- file2.war
server2:
- file1.war
- file2.war
- file3.war
and for n
I found myself wanting to iterate over a heterogeneous set of keys and their associated values and use the key-value pair in a task. The dict2items
filter is the least painful way I've found. You can find dict2items in Ansible 2.6
systemsetup:
remotelogin: "On"
timezone: "Europe/Oslo"
usingnetworktime: "On"
sleep: 0
computersleep: 0
displaysleep: 0
harddisksleep: 0
allowpowerbuttontosleepcomputer: "Off"
wakeonnetworkaccess: "On"
restartfreeze: "On"
restartpowerfailure: "On"
---
- debug:
msg: "KEY: {{ item.key }}, VALUE: {{ item.value }}"
loop: "{{ systemsetup | dict2items }}"
Now Ansible allows this
- name: add several users
user:
name: "{{ item.name }}"
state: present
groups: "{{ item.groups }}"
with_items:
- { name: 'testuser1', groups: 'wheel' }
- { name: 'testuser2', groups: 'root' }
Here is my preferred way to loop over dictionaries:
input_data.yml contains the following:
----
input_data:
item_1:
id: 1
info: "Info field number 1"
item_2:
id: 2
info: "Info field number 2"
I then use a data structure like the above in a play using the keys() function and iterate over the data using with_items:
---
- hosts: localhost
gather_facts: false
connection: local
tasks:
- name: Include dictionary data
include_vars:
file: data.yml
- name: Show info field from data.yml
debug:
msg: "Id: {{ input_data[item]['id'] }} - info: {{ input_data[item]['info'] }}"
with_items: "{{ input_data.keys() | list }}"
The above playbook produces the following output:
PLAY [localhost] ***********************************************************
TASK [Include dictionary data] *********************************************
ok: [localhost]
TASK [Show info field from data.yml] ***************************************
ok: [localhost] => (item=item_2) => {
"msg": "Id: 2 - info: Info field item 2"
}
ok: [localhost] => (item=item_3) => {
"msg": "Id: 3 - info: Info field item 3"
}
ok: [localhost] => (item=item_1) => {
"msg": "Id: 1 - info: Info field item 1"
}
PLAY RECAP *****************************************************************
localhost : ok=2 changed=0 unreachable=0 failed=0
Hows this
- hosts: localhost
vars:
war_files:
server1:
- file1.war
- file2.war
server2:
- file1.war
- file2.war
- file3.war
tasks:
- name: Loop over subelements of the dictionary
debug:
msg: "Key={{ item.0.key }} value={{ item.1 }}"
loop: "{{ war_files | dict2items | subelements('value') }}"
dict2items
, subelements
filters are coming in Ansible 2.6.
FYI, if a filter for your objective doesn't exist, you can write your own in python without having to resort to jinja2 hacks. Ansible is easily extendable; filters in filter_plugins/*.py
are searched by default adjacent to your plays/roles and are automatically included - see Developing Plugins for details.
EDIT: At the time of writing this answer, Ansible 2.6 wasn't out. Please read the answer provided by @tmoschou, as it is much better.
Well, I couldn't find a very easy way to do it, however, with a little bit of jinja2, we can achieve something of this sort:
/tmp ❯❯❯ cat example.yml
---
- hosts: 127.0.0.1
vars:
war_files:
server1:
- file1.war
- file2.war
server2:
- file1.war
- file2.war
- file3.war
tasks:
- set_fact:
war_files_list_of_dicts: |
{% set res = [] -%}
{% for key in war_files.keys() -%}
{% for value in war_files[key] -%}
{% set ignored = res.extend([{'Server': key, 'WAR':value}]) -%}
{%- endfor %}
{%- endfor %}
{{ res }}
- name: let's debug the crap out of this
debug: var=war_files_list_of_dicts
- name: Servers and their WARs!!!
debug:
msg: "Server={{ item.Server }}, WAR={{ item.WAR }}"
with_items: "{{ war_files_list_of_dicts }}"
And, when the playbook is run:
/tmp ❯❯❯ ansible-playbook example.yml
[WARNING]: provided hosts list is empty, only localhost is available
PLAY [127.0.0.1] ***************************************************************
TASK [setup] *******************************************************************
ok: [127.0.0.1]
TASK [set_fact] ****************************************************************
ok: [127.0.0.1]
TASK [let's debug the crap out of this] ****************************************
ok: [127.0.0.1] => {
"war_files_list_of_dicts": [
{
"Server": "server1",
"WAR": "file1.war"
},
{
"Server": "server1",
"WAR": "file2.war"
},
{
"Server": "server2",
"WAR": "file1.war"
},
{
"Server": "server2",
"WAR": "file2.war"
},
{
"Server": "server2",
"WAR": "file3.war"
}
]
}
TASK [Servers and their WARs!!!] ***********************************************
ok: [127.0.0.1] => (item={'WAR': u'file1.war', 'Server': u'server1'}) => {
"item": {
"Server": "server1",
"WAR": "file1.war"
},
"msg": "Server=server1, WAR=file1.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file2.war', 'Server': u'server1'}) => {
"item": {
"Server": "server1",
"WAR": "file2.war"
},
"msg": "Server=server1, WAR=file2.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file1.war', 'Server': u'server2'}) => {
"item": {
"Server": "server2",
"WAR": "file1.war"
},
"msg": "Server=server2, WAR=file1.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file2.war', 'Server': u'server2'}) => {
"item": {
"Server": "server2",
"WAR": "file2.war"
},
"msg": "Server=server2, WAR=file2.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file3.war', 'Server': u'server2'}) => {
"item": {
"Server": "server2",
"WAR": "file3.war"
},
"msg": "Server=server2, WAR=file3.war"
}
PLAY RECAP *********************************************************************
127.0.0.1 : ok=4 changed=0 unreachable=0 failed=0