- name: Create Dirs for rs disk
file:
name: "{{ /rs{{ items }}"
state: directory
with_sequence: start=1 end={{ disk_group[inventory_hostname]['rs'] | length }}
when: disk_group[inventory_hostname]['rs'] is defined
tasks
When "when" clause is false, how to avoid errors that vairable is undefined in "with_sequence".
In fact, use ignore_errors can do that, but I do think it's not a good idea.
You might want to try this example of include_tasks
> cat task.yml
- debug: var=item
with_sequence: start=1 end={{ rs|length }}
> cat playbook.yml
- hosts: localhost
vars:
# rs: test
tasks:
- include_tasks: task.yml
when: rs is defined
Related
Using ansible 2.9 I set a variable like this to store part of a group name
- name: set group
set_fact:
ansible_group: aaaa
I then want to use this variable in the following with_items clause:
- name: get
uri:
url: "http://{{ item }}:5324/kjhfg"
with_items: "{{ groups['thisgroup_{{ ansible_group }}'] }}"
However, using nested curly braces gives me the following error:
FAILED! => {"msg": "'dict object' has no attribute 'thisgroup_{{ ansible_group }}'"}
I also tried the following syntax variations
with_items: "{{ groups['thisgroup_ansible_group'] }}"
with_items: "groups['thisgroup_{{ ansible_group }}']"
with_items: "{{ groups['thisgroup_hostvars['localhost']['ansible_group']'] }}"
with_items: "{{ groups['thisgroup_hostvars[''localhost''][''ansible_group'']'] }}"
with_items: "{{ groups['thisgroup_hostvars[`localhost`][`ansible_group`]'] }}"
and probably one hundred other variations which all of them produced various errors
Can someone help me figure out the right syntax?
Simply concatenate the name of the group, e.g. given the inventory
shell> cat hosts
[thisgroup_aaaa]
host1
host2
host3
the playbook
- hosts: all
gather_facts: false
vars:
ansible_group: aaaa
_group: "{{ groups['thisgroup_' ~ ansible_group] }}"
tasks:
- debug:
var: item
loop: "{{ _group }}"
run_once: true
gives
item: host1
item: host2
item: host3
I'm trying to set a var only when a file exists, here is one of my attempts
---
- hosts: all
tasks:
- stat:
path: '{{ srch_path_new }}/bin/run'
register: result
- vars: srch_path="{{ srch_path_new }}"
when: result.stat.exists
This also didn't work
- vars: srch_path:"{{ srch_path_new }}"
The task you are looking for is called set_fact: and is the mechanism ansible uses to declare arbitrary "host variables", sometimes called "hostvars", or (also confusingly) "facts"
The syntax would be:
- set_fact:
srch_path: "{{ srch_path_new }}"
when: result.stat.exists
Also, while vars: is a legal keyword on a Task, its syntax is the same as set_fact: (or the vars: on the playbook): a yaml dictionary, not a key:value pair as you had. For example:
- debug:
msg: hello, {{ friend }}
vars:
friend: Jane Doe
and be aware that vars: on a task exist only for that task
I want 'lucy' to follow the user module creators' default behaviour which is to create and use a group matching the user name 'lucy'. However for 'frank' I want the primary group to be an existing one; gid 1003. So my hash looks like this:
lucy:
comment: dog
frank:
comment: cat
group: 1003
And my task looks like this:
- name: Set up local unix user accounts
user:
name: "{{ item.key }}"
comment: "{{ item.value.comment }}"
group: "{{ item.value.group | default(undef) }}"
loop: "{{ users|dict2items }}"
This doesn't work, as undef is not recognised. Nor is anything else I can think of. 'null', 'None' etc. all fail. '' creates an empty string which is not right either. I can't find out how to do it.
Any ideas?
default(omit) is what you are looking for. For example,
- name: Set up local Unix user accounts
user:
name: "{{ item.key }}"
comment: "{{ item.value.comment }}"
group: "{{ item.value.group | default(omit) }}"
loop: "{{ users|dict2items }}"
Comments
Comment by Lucas Basquerotto: "... omit only works correctly when used directly in a module, it won't work in a set_fact ..."
A: You're wrong. For example, default(omit) works both in set_fact and in the module. The first item in the list defaults to false with the result "VARIABLE IS NOT DEFINED!". The second item defaults to omit. Omitted parameter get_checksum defaults to true with the checksum in the results
shell> cat pb.yml
- hosts: localhost
tasks:
- set_fact:
test:
- "{{ gchk|default(false) }}"
- "{{ gchk|default(omit) }}"
- stat:
path: /etc/passwd
get_checksum: "{{ item }}"
loop: "{{ test }}"
register: result
- debug:
var: item.stat.checksum
loop: "{{ result.results }}"
gives
shell> ansible-playbook pb.yml | grep item.stat.checksum
item.stat.checksum: VARIABLE IS NOT DEFINED!
item.stat.checksum: 7c73e9f589ca1f0a1372aa4cd6944feec459c4a8
In addition to this, default(omit) works as expected also in some expressions. For example
- debug:
msg: "{{ {'a': item}|combine({'b': true}) }}"
loop: "{{ test }}"
gives
msg:
a: false
b: true
msg:
b: true
See the results without default values
shell> ansible-playbook pb.yml -e "gchk={{ true|bool }}"
I was a little bit surprised to discover that his piece of code fails with an IOError exception instead of defaulting to omitting the value.
#!/usr/bin/env ansible-playbook -i localhost,
---
- hosts: localhost
tasks:
- debug: msg="{{ lookup('ini', 'foo section=DEFAULT file=missing-file.conf') | default(omit) }}"
How can I load a value without raising an exception?
Please note that the lookup module supports a default value parameter but this one is useless to me because it works only when it can open the file.
I need a default value that works even when the it fails to open the file.
As far as I know Jinja2 unfortunately doesn't support any try/catch mechanism.
So you either patch ini lookup plugin / file issue to Ansible team, or use this ugly workaround:
---
- hosts: localhost
gather_facts: no
tasks:
- debug: msg="{{ lookup('first_found', dict(files=['test-ini.conf'], skip=true)) | ternary(lookup('ini', 'foo section=DEFAULT file=test-ini.conf'), omit) }}"
In this example first_found lookup return file name if file exists or empty list otherwise. If file exists, ternary filter calls ini lookup, otherwise omit placeholder is returned.
In case people like me stumble upon this question in 2022,
Ansible now supports rescue blocks, which is similar to try-catch-finally in programming languages.
Examples can be found in the official documentation Error handling with blocks.
You can use block/rescue as follows:
- hosts: localhost
tasks:
- block:
- debug: msg="{{ lookup('ini', 'foo section=DEFAULT file=missing-file.conf') }}"
rescue:
- debug: msg="omit"
You can also convert your input file with a from_yaml filter before using the default filter
- name: "load a yaml file or a default value"
set_fact:
myvar: "{{ lookup('file', 'myfile.yml', errors='ignore') | from_yaml | default(mydefaultObject, true) }}"
To avoid the error when the path doesn't exist, use a condition to check for the path before attempting the lookup:
---
- hosts: localhost
tasks:
- debug: msg="{{ lookup('ini', 'foo section=DEFAULT file=missing-file.conf') }}"
when: missing-file.conf | exists
You can use this with set_fact as well, then omit the undefined var when using it if required:
- hosts: localhost
tasks:
- set_fact:
foo: "{{ lookup('ini', 'foo section=DEFAULT file=missing-file.conf') }}"
when: missing-file.conf | exists
- debug:
var: foo # undefined
msg: "{{ foo | default(omit) }}" # omitted
Note that lookups and Jinja2 tests run on the controller. If you need to check the path on the host, use the stat and either slurp or fetch modules:
- stat:
file: missing-remote-file-with-text-i-want
register: file
- slurp:
src: missing-remote-file-with-text-i-want
register: slurp
when: file.stat.exists
- set_fact:
foo: "{{ slurp.content | b64decode }}"
when: file.stat.exists
- fetch:
src: missing-file.conf
dest: /tmp/fetched
fail_on_missing: False
- set_fact:
bar: "{{ lookup('ini', 'foo section=DEFAULT file=/tmp/fetched/' + inventory_hostname + '/missing-file.conf') }}"
when: ('/tmp/fetched/' + inventory_hostname + '/missing-file.conf') | exists
Second note, in Ansible v2.5 the grammar for using the path tests was changed, the format is now:
- set_fact:
foo: "{{ lookup('ini', 'foo section=DEFAULT file=missing-file.conf') }}"
when: missing-file.conf is exists
I have a role for a vpn server and some of them should be accessible to everyone, others only to admins.
Users and admins do not intersect, I want to use the variable only_admins that is True or False to toggle between these two.
I came up with this piece of configuration:
- name: Set vpn_users variable
set_fact: "vpn_users={{ users + admins}}"
when: ! only_admins
- name: Set vpn_users variable
set_fact: "vpn_users={{ admins }}"
when: only_admins
# works
- debug: "var={{ item }}"
with_items: users
# works
- debug: "var={{ item }}"
with_items: admins
# does not work
- debug: "var={{ item }}"
with_items: vpn_users
Any tips to get this working? Or other approaches?
Your syntax for set_fact is not good as per the documentation (http://docs.ansible.com/set_fact_module.html). You also use a lot of unnecessary quoting.
Here is a self-contained example that works fine :
---
- hosts: localhost
vars:
users:
- ua
- ub
admins:
- aa
- ab
tasks:
- debug: var=only_admins
- name: Set vpn_users variable to admins and users
set_fact:
vpn_users: "{{ users + admins }}"
when: not only_admins
- name: Set vpn_users variable to admins only
set_fact:
vpn_users: "{{ admins }}"
when: only_admins
- debug: var=item
with_items: users
- debug: var=item
with_items: admins
- debug: var=item
with_items: vpn_users
Try it with :
ansible-playbook test.yml --extra-vars '{ "only_admins": false }'
or :
ansible-playbook test.yml --extra-vars '{ "only_admins": true }'
Note that for debugging, you can print whatever var you'd like with the debug module. So instead of doing :
- debug: var=item
with_items: vpn_users
you just can do :
- debug: var=vpn_users
(ditto for the two preceding tasks).
This seems to work, didn't find out why the set_fact didn't work though:
- debug: "var={{ item }}"
with_items: "{{ admins if only_admins else (admins + users) }}"