how to put the result of an echo command into an ansible variable

Question

I have $MY_VAR set to some value on the remote host, and I want to query it from a playbook (put it's value in an ansible variable), here's what I am seeing :

 - name: put shell var into ansible var command: echo $MY_VAR register: my_var - debug: var=my_var

 ok: [192.168.78.10] => { "my_var": { "changed": true, "cmd": [ "echo", "$my_var" ], "delta": "0:00:00.002284", "end": "2014-12-17 18:10:01.097217", "invocation": { "module_args": "echo $my_var", "module_name": "command" }, "rc": 0, "start": "2014-12-17 18:10:01.094933", "stderr": "", "stdout": "$my_var", "stdout_lines": [ "$my_var" ] } }

note:

If I change the command to :

 command: pwd

then I get the expected result :

"my_var": { "stdout": "/home/vagrant", "stdout_lines": [ "/home/vagrant" ] }

It seems as if echo does not expand when called from ansible

Are you sure, this environment variable is accessible anytime you ssh to the remote host? If you ssh to the machine, does doing "echo $MY_VAR" print something? I mean env variables could be set per terminal instance, so is it possible that your env variable is set on one terminal, but if you start a new tab it might not be visible? — Akshar Raaj
– Akshar Raaj, Commented Dec 17, 2014 at 18:43
echo $MY_VAR on the remote host prints the expected value, it is set in the ~/.profile of the user — Boutran
– Boutran, Commented Dec 17, 2014 at 18:50

300D7309EF17 · Accepted Answer · 2014-12-17 21:00:01Z

8

The problem is that you are using the command module. Here's what the documentation says:

The given command will be executed on all selected nodes. It will not be processed through the shell, so variables like $HOME and operations like "<", ">", "|", and "&" will not work (use the shell module if you need these features).

So, use shell instead of command.

edited Dec 17, 2014 at 21:00

answered Dec 17, 2014 at 19:57

300D7309EF17

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3 Comments

Ramon de la Fuente Over a year ago

Doesn't lookup run locally? "These plugins are evaluated on the Ansible control machine"

keba Over a year ago

Its also worth noting that environment variables may not be loaded at all - Ansible doesn't connect with an interactive session, so .bash_profile for example will not be parsed when Ansible connects to the server, and any configuration on the remote server held in there will be ignored...

300D7309EF17 Over a year ago

@keba I agree, the whole thing is a big red flag. It seems like flagrant abuse of Ansible and configuration management.

brianc · Accepted Answer · 2023-01-23 18:49:09Z

Here's a way to do what you want to do, but without echo. Note you have to use braces to de-reference the variable.

- name: put shell var into ansible var set_fact: my_var: "{{ lookup('env','MY_VAR') }}" - name: print var debug: msg: var={{ my_var }}

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