Silly me .. I should re-read my own code before pressing 'send'!
- name: validate filename lookup value
assert:
that:
- my_var in file_table.keys()
fail_msg: "File lookup key '{{ my_var }}' is not valid"
success_msg: "File lookup key '{{ my_var }}' is valid"
- name: do my file-based task
debug:
msg: "File name is {{file_table[my_var] }}"
An added footnote .. keys() provides the dictionary keys in the lookup table as
a list.
vars:
file_table:
oracle: /apps/oracle/some/file/path
mysql: /apps/mysql/other/path
postgres: /apps/postgres/different/path
With this dictionary, file_table.keys() returns a list of [ mysql, oracle,
postgres ].The assert task tests my_var against that list. If my_var isn't one
of those values, the assert task fails. If my_var is one of those values, the
debug task prints the corresponding value associated with the key that my_var
provides. If my_var is oracle, the debug prints /apps/oracle/some/file/path.
Walter
--
Walter Rowe, Division Chief
Infrastructure Services, OISM
Mobile: 202.355.4123
On Jul 18, 2023, at 9:14 AM, 'Rowe, Walter P. (Fed)' via Ansible Project
<[email protected]> wrote:
If you didn't want a default value and instead wanted to gracefully handle an
invalid value you could do something like this:
- name: validate filename lookup value
assert:
that:
- my_var in file_table.keys()
fail_msg: "File lookup key '{{ my_var }}' is not valid"
success_msg: "File lookup key '{{ my_var }}' is valid"
- name: do my file-based task
debug:
msg: "File name is {{ artifacts[my_var] }}"
The "assert" task will fail the playbook if any of the tests fail (you can list
more than one test).
If all the tests pass then the playbook continues to the next task.
Walter
--
Walter Rowe, Division Chief
Infrastructure Services, OISM
Mobile: 202.355.4123
On Jul 18, 2023, at 8:51 AM, 'Rowe, Walter P. (Fed)' via Ansible Project
<[email protected]> wrote:
Todd's dictionary lookup is elegant and flexible. I'd go with that model.
It supports any number of choices and gracefully gives a default value.
Walter
--
Walter Rowe, Division Chief
Infrastructure Services, OISM
Mobile: 202.355.4123
On Jul 17, 2023, at 10:29 PM, Todd Lewis <[email protected]> wrote:
Hello, David.
You could use a lookup table implemented as a simple dict. If you only need it
in one task, you can define it in that task's vars section as I've done below,
or farther "up" in host_vars, group_vars, etc., as long as it's defined
somewhere. Here's a simple demo. I'm mapping colors to veggies, but you could
map to file names or whatever. Be sure to handle the "missing" case.
[utoddl@tango ansible]$ cat select-artifact.yml
---
- name: Select artifact based on value
hosts: localhost
gather_facts: false
tasks:
- name: Match an artifact based on a value
ansible.builtin.debug:
msg: "Value {{ item }} matches artifact {{ artifacts[item] |
default('!missing!') }}."
vars:
artifacts:
green: cucumbers
red: tomatoes
purple: cabage
yellow: squash
loop:
- red
- orange
- yellow
- green
- blue
- indigo
- violet
[utoddl@tango ansible]$ ansible-playbook select-artifact.yml
PLAY [Select artifact based on value]
*********************************************************
TASK [Match an artifact based on a value]
*****************************************************
ok: [localhost] => (item=red) => {
"msg": "Value red matches artifact tomatoes."
}
ok: [localhost] => (item=orange) => {
"msg": "Value orange matches artifact !missing!."
}
ok: [localhost] => (item=yellow) => {
"msg": "Value yellow matches artifact squash."
}
ok: [localhost] => (item=green) => {
"msg": "Value green matches artifact cucumbers."
}
ok: [localhost] => (item=blue) => {
"msg": "Value blue matches artifact !missing!."
}
ok: [localhost] => (item=indigo) => {
"msg": "Value indigo matches artifact !missing!."
}
ok: [localhost] => (item=violet) => {
"msg": "Value violet matches artifact !missing!."
}
PLAY RECAP
************************************************************************************
localhost : ok=1 changed=0 unreachable=0 failed=0
skipped=0 rescued=0 ignored=0
Cheers,
--
Todd
On 7/14/23 2:00 PM, David Nadelson wrote:
Hi All,
I'm a DBA learning to use ansible to automate. I'm wondering if anyone can
point me to docs on how to use ansible to select a file based on the value of a
variable. i.e. if variable=x than choose 1.txt if variable=y then choose
2.txt.
Thanks,
David
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