How to loop over this dictionary in Ansible?

问题:

Say I have this dictionary

war_files:
  server1:
  - file1.war
  - file2.war
  server2:
  - file1.war
  - file2.war
  - file3.war

and for now I just want to loop over each item (key), and then over each item in the key (value). I did this

- name: Loop over the dictionary
  debug: msg="Key={{ item.key }} value={{ item.value }}"
  with_dict: "{{ war_files }}"

And I get this. It is of course correct, but is NOT what I want.

ok: [localhost] => (item={'value': [u'file1.war', u'file2.war'], 'key': u'server1'}) => {
    "item": {
        "key": "server1", 
        "value": [
            "file1.war", 
            "file2.war"
        ]
    }, 
    "msg": "Server=server1, WAR=[u'file1.war', u'file2.war']"
}
ok: [localhost] => (item={'value': [u'file1.war', u'file2.war', u'file3.war'], 'key': u'server2'}) => {
    "item": {
        "key": "server2", 
        "value": [
            "file1.war", 
            "file2.war", 
            "file3.war"
        ]
    }, 
    "msg": "Server=server2, WAR=[u'file1.war', u'file2.war', u'file3.war']"
}

I want to get an output that says

"msg": "Server=server1, WAR=file1.war"
"msg": "Server=server1, WAR=file2.war"
"msg": "Server=server2, WAR=file1.war"
"msg": "Server=server2, WAR=file2.war"
"msg": "Server=server2, WAR=file3.war"

IOW, how can I write a task to iterates over the dictionary so it goes through each key, and then the items within each key? In essence, I have a nested array and want to iterate over it?

回答1:

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   

回答2:

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.

回答3:

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' }

回答4:

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() }}"

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

回答5:

dict2items

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

Example Dict

systemsetup:
  remotelogin: "On"
  timezone: "Europe/Oslo"
  usingnetworktime: "On"
  sleep: 0
  computersleep: 0
  displaysleep: 0
  harddisksleep: 0
  allowpowerbuttontosleepcomputer: "Off"
  wakeonnetworkaccess: "On"
  restartfreeze: "On"
  restartpowerfailure: "On"

Example Task

---
- debug:
    msg: "KEY: {{ item.key }}, VALUE: {{ item.value }}"
  loop: "{{ systemsetup | dict2items }}"