Ansible task variable output not displaying - ansible

Question

Below is my simple playbook
name: "test"
hosts: webservers
tasks:
- name: Echo my_env_var
shell: "echo $MY_ENV_VARIABLE"
environment:
MY_ENV_VARIABLE: whatever_value
- name: Echo my_env_var again
shell: "echo $MY_ENV_VARIABLE"
register: stdd
- debug: msg={{stdd.stdout_lines}}
My output is always msg:"" or msg: []. Why am i not able to see the value of variable

Answer 1

I took your example and changed it from debug msg to debug var. I also simplified it by only running the task once, and found the error in the process. The environment argument is specific to a task. You aren't including it in your second shell task.
Here's the example I used.
echo.yml
- hosts: localhost
tasks:
- name: Echo my_env_var
shell: "echo $MY_ENV_VARIABLE"
environment:
MY_ENV_VARIABLE: whatever_value
register: stdd
- debug: var=stdd
execution
$ ansible-playbook -c local -i "localhost," echo.yml
PLAY [localhost] **************************************************************
GATHERING FACTS ***************************************************************
ok: [localhost]
TASK: [Echo my_env_var] *******************************************************
changed: [localhost]
TASK: [debug var=stdd] ********************************************************
ok: [localhost] => {
"var": {
"stdd": {
"changed": true,
"cmd": "echo $MY_ENV_VARIABLE",
"delta": "0:00:00.005332",
"end": "2016-07-25 19:42:54.320667",
"invocation": {
"module_args": "echo $MY_ENV_VARIABLE",
"module_complex_args": {},
"module_name": "shell"
},
"rc": 0,
"start": "2016-07-25 19:42:54.315335",
"stderr": "",
"stdout": "whatever_value",
"stdout_lines": [
"whatever_value"
],
"warnings": []
}
}
}
PLAY RECAP ********************************************************************
localhost : ok=3 changed=1 unreachable=0 failed=0