Trellis: Check if deploy hook files exist before including them

[arashohadi]

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Background
I have one Vagrant box to manage multiple sites (around ~25). I have refrained from using deploy hooks (mainly build_before) since I have customized build workflows between different sites and at the moment, deploy hooks are applied to all sites within one Trellis instance.

I would like to have the possibility to have customized deploy hooks per site. It would ideally look something along the lines of build-before-site1.com.yml and allow me to create new deploy files if necessary that are customized to each site.

Example

• site1.com uses gulp to build my assets
• site2.com uses webpack to build my assets
• site3.com does not have a need for a build workflow

Problem
If a site does not have a deploy hook file (e.g. build-before-site3.com.yml), deploying via Ansible will fail saying that the file is missing. I could probably create an empty file to bypass the error but I have another suggestion.

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Feature Request

What I have that is working
I have changed roles/deploy/tasks/build.yml and added a check to make sure that the deploy_build_before file (referenced in deploy.yml) exists and added a when statement to only run the deploy-hook if it exists.

- name: Build before?
  local_action: stat path="{{ deploy_build_before }}"
  register: build_before

- include: "{{ deploy_build_before | default('../hooks/example.yml') }}"
  tags: deploy-build-before
  when: build_before.stat.exists

I can then do something like this in deploy.yml

vars:
    deploy_build_before: "{{ playbook_dir }}/deploy-hooks/build-before-{{ site }}.yml"
    deploy_build_after: "{{ playbook_dir }}/roles/deploy/hooks/build-after.yml"

And it will give me the opportunity to have a file in the deploy-hooks folder named build-before-site1.com.yml

Other relevant information
As far as I can tell this will not affect already existing Trellis instances but only extend the flexibility that the project already has. This could/should possibly be extended to all deploy hooks (if implemented) to be consistent throughout. So this is more of a request to see if it is interesting at all to the community or if I should keep using this as a custom modification for myself.

Final note
Thank you for your amazing efforts on this project. It has helped me immensely in my work and also in my personal development!

[swalkinshaw]

This seems like a useful addition but I'm wary of adding this for every hook. There is a cost in terms of performance for all these tasks and it matters more for deploys which should be fast as possible.

[arashohadi]

I understand the concerns for performance. If I can help in any way, just let me know.

[swalkinshaw]

This will be covered by https://github.com/roots/trellis/pull/815 as a nice bonus