Is it possible to skip some items in Ansible with_items loop operator, on a conditional, without generating an additional step?
Just for example:
- name: test task
command: touch "{{ item.item }}"
with_items:
- { item: "1" }
- { item: "2", when: "test_var is defined" }
- { item: "3" }
in this task I want to create file 2 only when test_var is defined.
The other answer is close but will skip all items != 2. I don't think that's what you want. here's what I would do:
- hosts: localhost
tasks:
- debug: msg="touch {{item.id}}"
with_items:
- { id: 1 }
- { id: 2 , create: "{{ test_var is defined }}" }
- { id: 3 }
when: item.create | default(True) | bool
The when: conditional on the task is evaluated for each item. So in this case, you can just do:
...
with_items:
- 1
- 2
- 3
when: item != 2 and test_var is defined
I had a similar problem, and what I did was:
...
with_items:
- 1
- 2
- 3
when: (item != 2) or (item == 2 and test_var is defined)
Which is simpler and cleaner.
I recently ran into this problem and none of the answers I found were exactly what I was looking for. I wanted a way to selectively include a with_item based on another variable.
Here is what I came up with:
- name: Check if file exists
stat:
path: "/{{item}}"
with_items:
- "foo"
- "bar"
- "baz"
- "{% if some_variable == 'special' %}bazinga{% endif %}"
register: file_stat
- name: List files
shell: echo "{{item.item | basename}}"
with_items:
- "{{file_stat.results}}"
when:
- item.stat | default(false) and item.stat.exists
When the above plays are run, the list of items in file_stat will only include bazinga if some_variable == 'special'
What you want is that file 1 and file 3 always gets created but file 2 is created only when test_var is defined. If you use ansible's when condition it works on complete task and not on individual items like this :
- name: test task
command: touch "{{ item.item }}"
with_items:
- { item: "1" }
- { item: "2" }
- { item: "3" }
when: test_var is defined
This task will check the condition for all three line items 1,2 and 3.
However you can achieve this by two simple tasks :
- name: test task
command: touch "{{ item }}"
with_items:
- 1
- 3
- name: test task
command: touch "{{ item }}"
with_items:
- 2
when: test_var is defined
Related
Let say, I have this directory structure:
# ls /root/ansible_test/
one two
And the playbooks looks like this:
- name: gathering all dirs
stat:
path: /root/ansible_test/{{ item }}/
register: dir_check
changed_when: false
check_mode: no
loop:
- "one"
- "two"
- "three"
- name: check all of the dirs are created
set_fact:
all_dirs_created: true
when: item.stat.exists == true
loop: "{{ dir_check.results }}"
- debug:
msg: "Not all dirs are created!"
when: all_dirs_created is not defined
My problem is that the "one" and "two" dirs are created, so the fact will be defined because if one dir exists, then the loop will return true. I also tried opposite and checked item.stat.exists == false but if one dir is not created (three) then fact will be created also.
I would like to play the task set_fact only if all of the item in the loop is true or if one of them is false. How do I achieve this in this case?
Q: set_fact only if all of the items in the loop are true or if one of them is false
A: Count the items. For example
- set_fact:
dirs_missing: "{{ _all|int - _exist|int }}"
vars:
_all: "{{ dir_check.results|length }}"
_exist: "{{ dir_check.results|
map(attribute='stat.exists')|
select|length }}"
gives (in your case)
dirs_missing: '1'
Now, you can set whatever you want, e.g.
- name: check all of the dirs are created
set_fact:
all_dirs_created: true
when: dirs_missing|int == 0
- debug:
msg: "Not all dirs are created!
(Exactly {{ dirs_missing }} missing.)"
when: all_dirs_created is not defined
gives
TASK [check all of the dirs are created] ********************************
skipping: [localhost]
TASK [debug] ************************************************************
ok: [localhost] =>
msg: Not all dirs are created! (Exactly 1 missing.)
You can simplify the code by using the filter counter from the latest collection Community.General. See Counting elements in a sequence, e.g.
- name: check all of the dirs are created
set_fact:
all_dirs_created: true
when: _counts[false] is not defined
vars:
_counts: "{{ dir_check.results|
map(attribute='stat.exists')|
community.general.counter }}"
The solutions above counted the items of the list to enable the evaluation of the option if one of them is false. The code can be simplified further if the counting of the items is not necessary. For example, test if all items are true
- name: check all of the dirs are created
set_fact:
all_dirs_created: true
when: dir_check.results|map(attribute='stat.exists') is all
However, then you have to test the existence of the variable all_dirs_created. More practical is setting both values. Ultimately, the expected functionality of your last two tasks can be reduced to the code below
- name: check all of the dirs are created
set_fact:
all_dirs_created: "{{ dir_check.results|
map(attribute='stat.exists') is all }}"
- debug:
msg: Not all dirs are created!
when: not all_dirs_created
Background:
We are providing an Ansible utility for the admins to add or remove comments in motd file. We want to restrict any direct edits to motd file. Since there can be previous comments we want to retain them. This means that we parse the file only once and capture existing comments. After which the admins have to use the tool to add/delete comments. Any comments directly added to the file will be discarded.
Requirement:
I have this block which needs to run only once. Not once per execution but once only for many executions. In other words, it should run the first time we execute the script but not after that.
Approach:
To accomplish this, I defined a flag variable and initialized it to 0 like this common_motd_qsc_flag: 0 in defaults/mail.yml. Once I executed a particular task I am trying to update the variable to 1 like this common_motd_qsc_flag: 1. Within the task, I am making sure that the task is executed only when the flag variable is 0 in using the when condition.
Problem:
Every time the script executes it is still running the task that shouldn't be run. I understand why this is happening. It is because during the start of the script it is reading common_motd_qsc_flag: 0 in defaults/main.yml.
Question:
Is there a way to update common_motd_qsc_flag: 1 in defaults/main.yml without using lineinfile module? Any alternative approaches are also appreciated if this an ugly way to handle this requirement.
tasks/main.yml:
- name: Parse all existing comments from /etc/motd
shell: tail --lines=+10 "{{ common_motd_qsc_motd_file }}"
register: existing_comments
when:
- motd_file.stat.exists == True
- common_motd_qsc_flag == 0 # defaults
- name: Update flag variable
set_fact:
common_motd_qsc_flag: 1
when: common_motd_qsc_flag == 0
- name: Add existing comments to the array
set_fact:
common_motd_qsc_comments_array: "{{ common_motd_qsc_comments_array | union([t_existing_entry]) }}"
loop: "{{ existing_comments.stdout_lines }}"
when:
- not t_existing_entry is search('Note:')
- not t_existing_entry is search('APPTYPE:')
- not t_existing_entry is search('Comments:')
- t_existing_entry not in common_motd_qsc_comments_array
vars:
t_existing_entry: "{{ item | trim }}"
defaults/main.yml:
common_motd_qsc_flag: 0
I was able to fix this using local facts as per your advice. Thanks much for the pointer. Here is the working code:
- name: Parse all existing comments from /etc/motd
shell: tail --lines=+10 "{{ common_motd_qsc_motd_file }}"
register: existing_comments
when:
- t_common_motd_qsc_check_qsc_file.stat.exists == True
- ansible_local['snps'] is defined
- ansible_local['snps']['cache'] is defined
- ansible_local['snps']['cache']['common_motd_qsc_flag'] is not defined
changed_when: false
- name: Add existing comments to the array
set_fact:
common_motd_qsc_comments_array: "{{ common_motd_qsc_comments_array | union([t_existing_entry]) }}"
loop: "{{ existing_comments.stdout_lines }}"
when:
- ansible_local['snps'] is defined
- ansible_local['snps']['cache'] is defined
- ansible_local['snps']['cache']['common_motd_qsc_flag'] is not defined
- not t_existing_entry is search('Note:')
- not t_existing_entry is search('APPTYPE:')
- not t_existing_entry is search('Comments:')
- t_existing_entry not in common_motd_qsc_comments_array
vars:
t_existing_entry: "{{ item | trim }}"
- name: Set common_motd_qsc_flag to facts file
ini_file:
dest: "/etc/ansible/facts.d/snps.fact"
section: 'cache' # [header]
option: 'common_motd_qsc_flag' # key
value: "1" # value
- name: Add a new comment if it does not exist
set_fact:
common_motd_qsc_comments_array: "{{ common_motd_qsc_comments_array | union([t_new_entry]) }}"
loop: "{{ common_motd_qsc_add_comment }}"
when:
- t_new_entry not in common_motd_qsc_comments_array
- t_new_entry|length > 0
vars:
t_new_entry: "{{ item | trim }}"
- name: Delete an existing comment
set_fact:
common_motd_qsc_comments_array: "{{ common_motd_qsc_comments_array | difference([t_new_entry]) }}"
loop: "{{ common_motd_qsc_delete_comment }}"
when:
- t_new_entry in common_motd_qsc_comments_array
- t_new_entry|length > 0
vars:
t_new_entry: "{{ item | trim }}"
- name: Save comments to snps.fact file
ini_file:
dest: "/etc/ansible/facts.d/snps.fact"
section: 'motd' # [header]
option: 'common_motd_qsc_comment_array' # key
value: "{{ common_motd_qsc_comments_array }}" # value
I am trying to use a register in Ansible playbook to store my output. Below is the code which i am using.
I have tried below code
- name: Check if Service Exists
stat: path=/etc/init.d/{{ item }}
register: {{ item }}_service_status
with_items:
- XXX
- YYY
- ZZZ
I need different outputs to be stored in different register variables based on the items as mentioned in the code. It is failing and not able to proceed. Any help would be appreciated.
Updated answer
I think you need to put quotes around it:
register: "{{ item }}_service_status"
Or you can use set_fact (1, 2, 3, 4)
register all the output to a single static variable output and then use a loop to iteratively build a new variable service_status (a list) by looping over each item in the static variable output
- name: Check if Service Exists
stat: path=/etc/init.d/{{ item }}
register: output
with_items:
- XXX
- YYY
- ZZZ
- name: Setting fact using output of loop
set_fact:
service_status:
- rc: "{{ item.rc }}"
stdout: "{{ item.stdout }}"
id: "{{ item.id }}"
with_items:
- "{{ output }}"
- debug:
msg: "ID and stdout: {{ item.id }} - {{ item.stdout }}"
with_items:
- "{{ service_status }}"
Initial Answer
IIUC, this link from the Ansible docs shows how to use register inside a loop (see another example in this SO post).
A couple of points
it may be more convenient to assign the list (XXX, YYY, ZZZ) to a separate variable (eg. 1, 2)
I don't know if this is part of the problem, but with_items is no longer the recommended approach to loop over a variable: instead use loop - see here for an example
vars:
items:
- XXX
- YYY
- ZZZ
- name: Check if Service Exists
stat: path=/etc/init.d/{{ item }}
register: service_status
loop: "{{ items|flatten(levels=1) }}"
- name: Show the return code and stdout
debug:
msg: "Cmd {{ item.cmd }}, return code {{ item.rc }}, stdout {{ item.stdout }}"
when: item.rc != 0
with_items: "{{ service_status.results }}"
I would like to add an item to a list in ansible dependent on some condition being met.
This doesn't work:
some_dictionary:
app:
- something
- something else
- something conditional # only want this item when some_condition == True
when: some_condition
I am not sure of the correct way to do this. Can I create a new task to add to the app value in the some_dictionary somehow?
You can filter out all falsey values with select(), but remember to apply the list() filter afterwards. This seems an easier and more readable approach for me:
- name: Test
hosts: localhost
gather_facts: no
vars:
mylist:
- "{{ (true) | ternary('a','') }}"
- "{{ (false) | ternary('b','') }}"
- "{{ (true) | ternary('c','') }}"
tasks:
- debug:
var: mylist|select|list
Result:
TASK [debug] *****************************************************************************************************************************************************************************************************************
ok: [localhost] => {
"mylist|select()|list": [
"a",
"c"
]
}
Replace (true) and (false) with whatever test you want.
Is there a reason you have to do everything in one go?
This is pretty easy if you specify the additional item(s) to add in separate vars, as you can just do list1 + list2.
---
- hosts: localhost
gather_facts: False
connection: local
vars:
mylist:
- one
- two
mycondition: False
myconditionalitem: foo
tasks:
- debug:
msg: "{{ mylist + [myconditionalitem] if mycondition else mylist }}"
I'd try to avoid this, but if conditional list is absolutely necessary, you can use this trick:
---
- hosts: localhost
gather_facts: no
vars:
a: 1
b: 1
c: 2
some_dictionary:
app: "{{ '[\"something\", \"something else\"' + (a + b == c) | ternary(', \"something conditional\"',' ') + ']' }}"
tasks:
- debug: var=some_dictionary.app
It will form an array-like string (["item1","item2","item3"]) and ansible variable templator will convert it into list before assigning to app.
Based on Konstantin's solution I developed the following:
- hosts: localhost
gather_facts: no
vars:
a: "{{ True if var1|d(True) else False }}"
b: "{{ True if var2|d(False) else False }}"
n: "{{ True if var2|d(True) else False }}"
some_list: "{{ '[' +
a|ternary('\"item1\",',' ') +
b|ternary('\"item2\",',' ') +
n|ternary('\"itemN\",',' ') + ']' }}"
tasks:
- debug: var=some_list
This will create a list with items "item1" till "itemN", but each item is only appended if the corresponding flag expands to 'True'.
Hope, this helps.
I want to add keys to a dictionary when using set_fact with with_items. This is a small POC which will help me complete some other work. I have tried to generalize the POC so as to remove all the irrelevant details from it.
When I execute following code it is shows a dictionary with only one key that corresponds to the last item of the with_items. It seems that it is re-creating a new dictionary or may be overriding an existing dictionary for every item in the with_items. I want a single dictionary with all the keys.
Code:
---
- hosts: localhost
connection: local
vars:
some_value: 12345
dict: {}
tasks:
- set_fact: {
dict: "{
{{ item }}: {{ some_value }}
}"
}
with_items:
- 1
- 2
- 3
- debug: msg="{{ dict }}"
This can also be done without resorting to plugins, tested in Ansible 2.2.
---
- hosts: localhost
connection: local
vars:
some_value: 12345
dict: {}
tasks:
- set_fact:
dict: "{{ dict | combine( { item: some_value } ) }}"
with_items:
- 1
- 2
- 3
- debug: msg="{{ dict }}"
Alternatively, this can be written without the complex one-liner with an include file.
tasks:
- include: append_dict.yml
with_items: [1, 2, 3]
append_dict.yml:
- name: "Append dict: define helper variable"
set_fact:
_append_dict: "{ '{{ item }}': {{ some_value }} }"
- name: "Append dict: execute append"
set_fact:
dict: "{{ dict | combine( _append_dict ) }}"
Output:
TASK [debug]
*******************************************************************
ok: [localhost] => {
"msg": {
"1": "12345",
"2": "12345",
"3": "12345"
}
}
Single quotes ' around {{ some_value }} are needed to store string values explicitly.
This syntax can also be used to append from a dict elementwise using with_dict by referring to item.key and item.value.
Manipulations like adding pre- and postfixes or hashes can be performed in the same step, for example
set_fact:
dict: "{{ dict | combine( { item.key + key_postfix: item.value + '_' + item.value | hash('md5') } ) }}"
Use a filter plugin.
First, make a new file in your ansible base dir called filter_plugins/makedict.py.
Now create a new function called "makedict" (or whatever you want) that takes a value and a list and returns a new dictionary where the keys are the elements of the list and the value is always the same.
class FilterModule(object):
def filters(self):
return { 'makedict': lambda _val, _list: { k: _val for k in _list } }
Now you can use the new filter in the playbook to achieve your desired result:
- hosts: 127.0.0.1
connection: local
vars:
my_value: 12345
my_keys: [1, 2, 3]
tasks:
- set_fact: my_dict="{{ my_value | makedict(my_keys) }}"
- debug: msg="{{ item.key }}={{ item.value }}"
with_dict: "{{my_dict}}"
You can customize the location of the filter plugin using the filter_plugins option in ansible.cfg.
this does not seems to work any more on ansible 2.5
---
- hosts: localhost
connection: local
vars:
some_value: 12345
dict: {}
tasks:
- set_fact:
dict: "{{ dict | combine( { item: some_value } ) }}"
with_items:
- 1
- 2
- 3
- debug: msg="{{ dict }}"
returns only last value {"dict":{"3": "some value"}}
I suggest you could do this :
- set_fact:
__dict: |
{% for item in [1,2,3] %}
{{item}}: "value"
{% endfor %}
- set_fact:
final_dict: "{{__dict|from_yaml}}"
- debug:
var: final_dict
Another solution could be this one, tested in Ansible 2.9.6.
This solutions adds the extra benefit that you do not have to declare _dict beforehand in vars section. This is achieved by the | default({}) pipe which ensures that the loop will not fail in the first iteration when _dict is empty.
In addition, the renaming of dict to _dict is necessary since the dict is a special keyword reserved for <class 'dict'>. Referenced (unfortunately only at devel branch yet) here.
---
- hosts: localhost
connection: local
vars:
some_value: 12345
tasks:
- set_fact:
_dict: "{{ _dict | default({}) | combine( { item: some_value } ) }}"
with_items:
- 1
- 2
- 3
- debug: msg="{{ _dict }}"