include datadog_skip_install

[rockaut]

fixes #430

• Include a default datadog_skip_install variable set to false/no as default
• Don't override datadog_skip install in set-parse-version.yml but check if its set or use default false

[bkabrda]

Hi 👋 thanks for sending the PR! While I do agree with the idea of making this configurable, I think that if user provides an explicit value, it should override all further assignments to the variable.

I think the way this should work is that we assign e.g. an empty string to the variable in defaults/main.yml. Then in the tasks/set-parse-version.yml file:

• If the value is empty string, do all the assignments that we do now.
• If the value is not empty string, take it and skip all the assignments that we do now.

Does this make sense?

[rockaut]

You mean if the user passes the variable with extra_var/cli? This takes already precedence over the variable in inventory (https://docs.ansible.com/ansible/latest/reference_appendices/general_precedence.html).

That said, you are right that currently something is not working. I today learned, that set_fact for variables is not "called" as whole if the variable is passed with extra_vars. This creates problems on boolean variables in newer Ansible versions as cli extra_vars are string type. I always thought one could then call |bool in set_fact but this doesn't work as said.

So there could be two solutions:

1. set the variable datadog_skip_install but then actually create a _datadog_skip_install converted one for example in set-parse-version.yml...
2. ... or just use datadog_skip_install|bool instead if the variable is used.

As the datadog_skip_install isn't used that often I would go with variant 2.

Beside the declaration of datadog_skip_install in defaults/main.yml has the nice side effect that one less task call is needed as set_fact in set-parse-version.yml is actually not needed anymore.

[rockaut]

Done...

Without the variable set in inventory or cli, the agent will be installed:

datadog-agent on  main [✘!?] took 7s
❯ ansible-playbook site.yml -i inventories/hosts.yml --limit host01p

PLAY [linux] ***************************************************************************************************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [set_fact] ************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [include_role : datadog.datadog] **************************************************************************************************************************************************************************************************************************************************************************************

TASK [datadog.datadog : Include Gather Ansible Facts task on Ansible >= 2.10] **********************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/facts-ansible10.yml for host01p

TASK [datadog.datadog : Gather Ansible Facts] ******************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Include Gather Ansible Facts task on Ansible < 2.10] ***********************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Check if OS is supported] **************************************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/os-check.yml for host01p

TASK [datadog.datadog : Fail if OS is not supported] ***********************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Resolve datadog_tracked_checks later to defend against variable presidence issues arising from dynamically included null datadog_checks] ***********************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/sanitize-checks.yml for host01p

TASK [datadog.datadog : Defend against defined but null datadog_checks variable] *******************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Resolve datadog_tracked_checks] ********************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Check that datadog_checks is a mapping] ************************************************************************************************************************************************************************************************************************************************************
ok: [host01p] => {
    "changed": false,
    "msg": "All assertions passed"
}

TASK [datadog.datadog : Set Facts for Datadog Agent Major Version] *********************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/set-parse-version.yml for host01p

TASK [datadog.datadog : Convert datadog_agent_major_version to string] *****************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : include_tasks] *************************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Set Agent default major version] *******************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Debian Install Tasks] ******************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : RedHat Install Tasks] ******************************************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/pkg-redhat.yml for host01p

...

PLAY RECAP *****************************************************************************************************************************************************************************************************************************************************************************************************************
host01p                   : ok=12   changed=0    unreachable=0    failed=0    skipped=5    rescued=0    ignored=0

with overriding the variable in cli the install step will be skipped:

datadog-agent on  main [✘!?] took 7s
❯ ansible-playbook site.yml -i inventories/hosts.yml --limit host01p -e datadog_skip_install=yes

PLAY [linux] ***************************************************************************************************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [set_fact] ************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [include_role : datadog.datadog] **************************************************************************************************************************************************************************************************************************************************************************************

TASK [datadog.datadog : Include Gather Ansible Facts task on Ansible >= 2.10] **********************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/facts-ansible10.yml for host01p

TASK [datadog.datadog : Gather Ansible Facts] ******************************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Include Gather Ansible Facts task on Ansible < 2.10] ***********************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Check if OS is supported] **************************************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/os-check.yml for host01p

TASK [datadog.datadog : Fail if OS is not supported] ***********************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Resolve datadog_tracked_checks later to defend against variable presidence issues arising from dynamically included null datadog_checks] ***********************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/sanitize-checks.yml for host01p

TASK [datadog.datadog : Defend against defined but null datadog_checks variable] *******************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Resolve datadog_tracked_checks] ********************************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : Check that datadog_checks is a mapping] ************************************************************************************************************************************************************************************************************************************************************
ok: [host01p] => {
    "changed": false,
    "msg": "All assertions passed"
}

TASK [datadog.datadog : Set Facts for Datadog Agent Major Version] *********************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/set-parse-version.yml for host01p

TASK [datadog.datadog : Convert datadog_agent_major_version to string] *****************************************************************************************************************************************************************************************************************************************************
ok: [host01p]

TASK [datadog.datadog : include_tasks] *************************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Set Agent default major version] *******************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Debian Install Tasks] ******************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : RedHat Install Tasks] ******************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Suse Install Tasks] ********************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Windows Install Tasks] *****************************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Linux Configuration Tasks (Agent 5)] ***************************************************************************************************************************************************************************************************************************************************************
skipping: [host01p]

TASK [datadog.datadog : Linux Configuration Tasks] *************************************************************************************************************************************************************************************************************************************************************************
included: /mnt/c/Users/fism/code/work/datadog-agent/roles/datadog.datadog/tasks/agent-linux.yml for host01p

...

I've tested this agains RHEL Linux. Can someone test this with windows?

[bkabrda]

Hi 👋 What I meant in my previous comment is that if datadog_skip_install is provided explicitly by the user, we should skip all the other tasks that possibly set it - see https://github.com/DataDog/ansible-datadog/blob/main/tasks/parse-version.yml#L85-L93. I think the best way to do it is to set it to e.g. empty string in the defaults/main.yml file. Then in tasks/parse-version.yml:

• If datadog_skip_install is empty string, we know that the user didn't provide explicit true/false, hence we let the tasks currently living in the tasks/parse-version.yml file do what they do now.
• If datadog_skip_install is not an empty string, we know that the user provided an explicit value. So we should take that value and not modify datadog_skip_install by further tasks in the tasks/parse-version.yml file.

In terms of the |bool conversion, I'd much prefer doing this in one place - the tasks/parse-version.yml file - to centralize how we create that variable and just be sure we have a boolean everywhere else.

[rockaut]

I think I see what you mean. I had a rough week and going into easter vacation, but will look into it next week.

[amenon90]

Any updates with this PR? We are looking for this exact implementation to be available for our use case. We are creating VM image with a specific agent version and holding it While the checks and configuration bit is done when the VM is provisioned and doesn't need to install datadog agent.