ansible debug msg failed_when and changed_when - automation

Question

y code -
# Update apt cache reposoitary
- name: Update apt cache
command: apt-get update
register: return
# Debug msg
- debug:
msg: '{{ return }}'
result.stdout_lines
"stdout_lines": [
"Hit:1 http://server/pub/mirrors/ubuntu bionic InRelease",
"Get:2 http://server/pub/mirrors/ubuntu bionic-updates InRelease [88.7 kB]",
"Get:3 http://server/pub/mirrors/ubuntu bionic-backports InRelease [74.6 kB]",
"Hit:4 https://download.package.com/infrastructure_agent/linux/apt bionic InRelease",
"Hit:5 https://archive.repo.package.com/apt/ubuntu/18.04/amd64/2018.3 bionic InRelease",
"Get:6 http://server/pub/mirrors/ubuntu bionic-security InRelease [88.7 kB]",
"Hit:7 http://apt.package123.org/pub/repos/apt bionic-pgdg InRelease",
"Fetched 252 kB in 1s (222 kB/s)",
"Reading package lists..."
I would like consider if any one line has 2 string "Err" & "package" that means it has failed to update apt cache from website - https://download.package.com/
I was thinking of something like below:
changed_when: >
(("Get" in return.stdout_lines) and
("package" in ret.stdout_lines)) or
(("Hit" in return.stdout_lines) and
("package" in ret.stdout_lines))
failed_when: >
("Err" in return.stdout_lines) and
("package" in ret.stdout_lines)
Question here is does 2 strings looks for all of the lines or line by line ?
if so how to get this worked on line by line check.

Answer 1

When APT fails to download the package, it will return an error. In that case, stdout isn't used anymore, but stderr. So you most likely need to change it to:
# Update apt cache reposoitary
- name: Update apt cache
command: apt-get update
ignore_errors: true
register: return
# Debug msg
- debug:
msg: '{{ return }}'
changed_when: >
(("Get" in return.stderr_lines) and
("newrelic" in ret.stderr_lines)) or
(("Hit" in return.stderr_lines) and
("newrelic" in ret.stdout_lines))
failed_when: >
("Err" in return.stderr_lines) and
("newrelic" in ret.stderr_lines)
Question here is does 2 strings looks for all of the lines or line by line ?
A: It looks for all the 'text' in the stderr_lines output of that task.
If so how to get this worked on line by line check.
A: Your code looks sane.
Perhaps you want to test this specific use case yourself. What you could do is append the following to /etc/hosts on your target system: 127.0.0.1 download.newrelic.com
This way, APT looks on the target machine for the repository. Since it isn't there, the download will fail.
Also note that Ansible has update cache built-in the APT module.

Answer 2

Here you go working code -
-----------------
# Update apt cache reposoitary
- name: Update apt cache
command: apt-get update
register: return
failed_when: return.stdout_lines is search("Hit:* https://download.package.com")
changed_when: return.stdout_lines is search("Err:* https://download.package.com")
# Debug msg
- debug:
msg: '{{ return }}'
-----------------