I am trying to remove the last character of the below output but I am having trouble doing it:
- debug:
msg: "{{ ansible_mounts|json_query('[?mount == `/`].device') }}"
register: rootpart
The below works with simple text:
- debug:
msg: "{{ '/dev/sda4'[:-1] }}"
But not with a variable:
- debug:
msg: "{{ rootpart[:-1] }}"
Error:
msg: Unexpected templating type error occurred on ({{ rootpart[:-1] }}): unhashable type: 'slice'
There is a big "don't" in your current attempt: you should not register on a debug task.
If you want to create a new variable, then use the set_fact module.
This is not only a better way to do it, it is also saving you from having a dictionary with the keys changed, failed and msg to dive into in order to get the variable you were expecting out of the msg property.
Then, your json_query is going to return you a list of devices, no matter if there is only one match thanks to your filter. So, you also need to get the first element of this list.
So, with all this, here are your two tasks:
- set_fact:
root_part: "{{ ansible_mounts | json_query(_query) }}"
vars:
_query: "[?mount == `/`].device | [0]"
- debug:
var: root_part[:-1]
Related
Example playbook -
---
- hosts: localhost
vars:
lesson:
name: Physics
students:
- Bob
- Joe
tasks:
- name: Display student names
debug:
msg: '{{ item }}'
loop: "{{ lesson.students }}"
when: item | default("")
The above playbook works well to output the student names.
However, if the input changes (as per below) such that no student names have been defined, then an error occurs. Is there a simple way to have the playbook skip this task if the list is undefined as per the input below? I realize it would work if the input specifies students: [], but as this input is coming from simple users, they're not going to know this. Much Thanks!
vars:
lesson:
name: Physics
students:
Error: fatal: [localhost]: FAILED! =>
msg: 'Invalid data passed to ''loop'', it requires a list, got this instead: . 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.
Update - I've tried the below variations but still get the same error -
---
- hosts: localhost
vars:
lesson:
name: Physics
students:
tasks:
- name: Display student names variation 1
debug:
msg: '{{ item }}'
loop: "{{ lesson.students }}"
when: lesson.students is iterable
- name: Display student names variation 2
debug:
msg: '{{ item }}'
loop: "{{ lesson.students }}"
when: lesson.students is not none
- name: Display student names variation 3
debug:
msg: '{{ item }}'
loop: "{{ lesson.students }}"
when: ( item | default("") ) or ( item is not none )
The real problem is that loop requires a list, even if it is an empty list.
If your var is undefined/None/empty string, it exists but is not a list and your when condition will never get evaluated because loop will fire an error before it is ever reached.
You have to default your var to an empty list in such cases, which will lead to a 0 size loop equivalent to skipping the task.
Since your var is defined but None you need to use the second optional parameter to default so that empty/false values are replaced as well
Note: I used the short alias d to default in my below examples
- name: Display student names
debug:
msg: '{{ item }}'
loop: "{{ lesson.students | d([], true) }}"
A good practice here that would have nipped that error in the bud would be to have a coherent data declaration by either:
not declaring the key at all and use a simple default i.e.
# ... #
vars:
lesson:
name: Physics
# ... #
loop: "{{ lesson.students | d([]) }}"
declare an empty list for the key rather than a None value i.e.
# ... #
vars:
lesson:
name: Physics
students: []
# ... #
loop: "{{ lesson.students }}"
My first proposition is the safest in this case anyway and will work in for all the above vars declarations.
There is a difference between an undefined variable, and variable having None value.
When you set variable name, but leave the right hand side empty. The variable is defined, but it is set to NoneType.
So your when: condition should have additional check for NoneType:
- hosts: localhost
vars:
lesson:
name: Physics
students:
tasks:
- name: Display student names
debug:
msg: '{{ item }}'
loop: "{{ lesson.students }}"
when: ( item | default("") ) or ( item is not none )
This will give:
skipping: [localhost] => (item=None)
Is it possible to include a JSON query in the actual task? All of the examples show using an additional var for the query.
Taking the example from Ansible Filters
- name: "Display all ports from cluster1"
debug:
var: item
loop: "{{ domain_definition | json_query(server_name_cluster1_query) }}"
vars:
server_name_cluster1_query: "domain.server[?cluster=='cluster1'].port"
Converted to:
- name: "Display all ports from cluster1"
debug:
var: item
loop: "{{ domain_definition | json_query(domain.server[?cluster=='cluster1'].port) }}"
as is it returns:
FAILED! => {"reason": "Syntax Error while loading YAML.\n found unknown escape character '?'
I have tried to add an escape backslash before the question mark, but it still fails with:
"template error while templating string: unexpected char '?'
It's possible to use back-ticks ` . For example
- name: "Display all ports from cluster1"
debug:
var: item
loop: "{{ domain_definition | json_query('domain.server[?cluster==`cluster1`].port') }}"
(not tested)
Ok it appears you can escape double quote the query and it will work!
- name: "Display all ports from cluster1"
debug:
var: item
loop: "{{ domain_definition | json_query(\"domain.server[?cluster=='cluster1'].port\") }}"
To step a little bit aside from escape hell, I like to take advantage of yaml scalar blocks
- name: "Display all ports from cluster1"
vars:
my_query: >-
domain.server[?cluster=='cluster1'].port
debug:
var: item
loop: "{{ domain_definition | json_query(my_query) }}"
You don't have to escape anything this way (works for quotes and backslash as well, nice for regexps)
I'm writing a playbook and want to loop a role over a variable that gets its value from the user. however that value might not always be a list of items, it might be a single value and whenever that happens it throws an error.
My Task:
- name: task name
include role:
name: role name
vars:
cluster_name: '{{ item }}'
loop: "{{ list_or_not }}"
loop_control:
loop_var: item
error:
...Invalid data passed to 'loop', it requires a list...
Have you tried the: "| list" filter?
Sorry cannot test at the moment.
You could test if the variable is a string, and if so, transform it into a single-item list. Something like this:
---
- hosts: localhost
gather_facts: false
tasks:
- set_fact:
list_or_not: ["{{ list_or_not }}"]
when: list_or_not is string
- debug:
msg: "{{ item }}"
loop: "{{ list_or_not }}"
i am testing looping code on ansible my first try worked:
- file:
state: touch
path: /tmp/{{ item }}
with_sequence: start=0 end={{ find_result.examined }}
this works the directorys are created
but if i use the same loop to create users i get an error
- name: User Creation
user:
name: "{{ find_result.files[item].path | regex_replace('/root/00staging/sshkeys/') | regex_replace('_id_rsa.pub')}}"
comment: nameduser
password: "{{ 'Start123' | password_hash('sha512') }}"
update_password: on_create
createhome: true
group: wheel
register: users_added
with_sequence: start=0 end={{ find_result.examined }}
The error:
{"msg": "The task includes an option with an undefined variable. The error was: 'list object' has no attribute u'0'\n\n
it works when i use the loop with_items but this is not dynamic enough
the variable is not empty it gets filled by this code:
- name: finding files
find:
paths: "/root/00staging/sshkeys"
file_type: "file"
register: find_result
Update:
i have the same error with simple sequence numbers the [item] is not getting filled but the {{ item }} gets filled correctly
find_result.files[item].path
with_sequence: start=0 end=1
The error you're seeing:
'list object' has no attribute u'0'
Suggests that the value of the find_result.files key is an empty list. In the first iteration of your loop you're trying to access find_result.files[0], but if that list is empty there is no element 0. You can generate the same error with the following example:
---
- hosts: localhost
gather_facts: false
vars:
empty_list: []
tasks:
- debug:
msg: "item {{ item }} is {{ empty_list[item] }}"
with_sequence: start=0 end=1
You should inspect the contents of the find_result variable (using e.g. a debug task) to confirm that it contains what you think it should contain.
Thanks to other stackoverflow users, I have managed to pull some data out of a variable registered by the digital_ocean ansible module. I attempted to use loop_control to print only part of the huge variable that is registered. Here is an extract from the role:
- name: Add droplet
digital_ocean: >
{ some parameters }
with_dict: "{{ droplets_up }}"
register: my_droplet
- debug: msg="Droplet IP is {{ item.droplet.ip_address }}"
with_items: "{{ my_droplet.results }}"
loop_control:
label: "{{ item }}"
I'm obviously doing it wrong here, as it prints the whole variable as well as the debug message. I don't quite understand loop_control at this point, but does anyone know if it's possible to use it in this manner with this module?
debug action has result['_ansible_verbose_always'] = True, so it will always print full item, no matter what your label is (although label: "{{item}}" doesn't change anything, try label: "{{ item.droplet.ip_address }}").
If you just need to list all your IP addresses, use map filter and single debug statement:
- name: Print droplets IP
debug:
msg: "{{ my_droplet.results | map(attribute='droplet.ip_address') | list }}"