[Best practices] Extend an occupied hook

trellis
1

It doesn’t seem to be possible using an ansible list for a hook file path.

I want to extend the deploy_build_after hook file, adding new functionality while preserving the original one (from Trellis). I want to avoid editing the file directly for better pulling+merging further Trellis updates (I use trellis as normal git repository and pull from GitHub).

2

There really isn’t one right now unfortunately. Which kind of defeats the purpose of hooks a bit :frowning:

We might be able to use Jinja inheritance for them. Want to create an issue for this?

3

I haven’t tried, but how about overriding deploy_build_after with your own include?

# deploy.yml
- deploy_build_after: "{{ playbook_dir }}/roles/deploy/hooks/build-after.yml"
+ deploy_build_after: "{{ playbook_dir }}/deploy-hooks/build-after.yml"

Then in your custom build-after.yml, just include the original

# deploy-hooks/build-after.yml

- name: some task
  command: stuff

# original tasks
- include: "{{ playbook_dir }}/roles/deploy/hooks/build-after.yml"

- name: some task
  command: more stuff
4

Created a new issue: https://github.com/roots/trellis/issues/814

5

That would be good, but it doesn’t seem to work, does it? In my test deployment just stopped before doing the build_after stuff, no error message or so.

6

@mockey Thanks for trying and reporting back. Trying just now, I get the same result. It’s baffling that the play just stops with no errors.

I think a “task include” parses and loads things a little differently than regular and has a problem with the usage of a default containing a quoted string. Here’s an example of changes Trellis might make to enable the nested include strategy above to succeed.

Remove this default . . .

# roles/deploy/tasks/build.yml
- - include: "{{ deploy_build_after | default('../hooks/example.yml') }}"
+ - include: "{{ deploy_build_after }}"

. . . placing the default in roles/deploy/defaults/main.yml instead:

# roles/deploy/defaults/main.yml
+ deploy_build_after: ../hooks/example.yml

There may be something Ansible needs to fix upstream, but perhaps Trellis could make this implementation adjustment for all deploy hooks in order to facilitate nested includes.

7

Yes, this whole include stuff seems a bit weird to me in Ansible.

It’s pretty cool that you figured that out, might really make sense to implement it this way.

8

Wouldn’t this be then an issue in ansible?

9

A fix proposed to Ansible upstream in ansible/ansible#23202