Create a list from a dictionary cycle

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1

Hi

I would like to create a list with this dict

{ “v3bf33-srv01”: “eu-west0-a”,

“v3bf33-srv02”: “eu-west0-a”,
“v3bf33-srv03”: “eu-west0-a”,
“v3bf33-srv04”: “eu-west0-b”,

“v3bf33-srv05”: “eu-west0-b”,

“v3bf33-srv06”: “eu-west0-b”,

“v3bf33-srv07”: “eu-west0-c”,
“v3bf33-srv08”: “eu-west0-c”,

“v3bf33-srv09”: “eu-west0-c” }

if a user ask 5 servers ( in a pipeline), cycle through servers of each value:

eu-west0-a,

eu-west0-b,

eu-west0-c,

then again , eu-west0-a, eu-west0-b, eu-west0-c … until reach number of server need

The result should be a list containing only the server name.

E.g.:

  • v3bf33-srv01 #eu-west0-a

  • v3bf33-srv04 #eu-west0-b

  • v3bf33-srv07 #eu-west0-c

  • v3bf33-srv02 #eu-west0-a -
    v3bf33-srv05 #eu-west0-b

any help is welcome. ^^

2

For example, the playbook below

cat pb.yml

- hosts: localhost
  vars:
    servers:
      srv01: a
      srv02: a
      srv03: a
      srv04: b
      srv05: b
      srv06: b
      srv07: c
      srv08: c
      srv09: c
    arr: "{{ servers|dict2items|
                     groupby('value')|
                     map(attribute=1)|
                     map('map', attribute='key')|
                     list }}"
    list_of_servers: "{{ tarr|flatten }}"
  tasks:
    - set_fact:
        tarr: "{{ tarr|d(arr.0)|zip(item)|map('flatten') }}"
      loop: "{{ arr[1:] }}"
    - debug:
        var: list_of_servers[:5]|to_yaml

1) Creates the matrix

  arr:
    - [srv01, srv02, srv03]
    - [srv04, srv05, srv06]
    - [srv07, srv08, srv09]

2) Transpose the matrix

  tarr:
    - [srv01, srv04, srv07]
    - [srv02, srv05, srv08]
    - [srv03, srv06, srv09]

3) Get the slice

  list_of_servers[:5]: [srv01, srv04, srv07, srv02, srv05]

3

it s not working for me :

fatal: [localhost]: FAILED! =>
{“msg”: "Invalid data passed to ‘loop’, it requires a list, got this instead: <generator object do_map at 0x7fe97cca3900>,

<generator object do_map at 0x7fe97cca39e0>, <generator object do_map at 0x7fe97cca3a50>].

Hint: If you passed a list/dict of just one element, try adding wantlist=True to your lookup invocation or use q/query instead of lookup."}

a co worker try too … .same result. i think i will go in BASH… i am sure it will work . ahahah

4

When i do

arr: “{{ servers|dict2items|
groupby(‘value’)|
map(attribute=1)|
map(‘map’, attribute=‘key’)|
list }}”
list_of_servers: “{{ tarr|flatten }}”
tasks:

  • debug:
    var: arr

the result , no data.

TASK [debug] ******************************************************************************************************************************
ok: [localhost] => {
“arr”: “[<generator object do_map at 0x7f1c51cac4a0>, <generator object do_map at 0x7f1c51cac9e0>,
<generator object do_map at 0x7f1c51caca50>]”
}

5

I think there’s an typo here. There’s an extra ‘t’ in list_of_servers: “{{ tarr|flatten }}” should be
list_of_servers: “{{ arr|flatten }}”

6

thx for looking, but the error come from the task débug:

tasks:

  • debug:
    var: arr

not tarr .