Support script files in addition to inline scripts for provisioners.

[Ranjandas]

Can the provisioners point to script files as an alternate option to inline scripts? This will be very useful when we have a bunch of templates that share many script blocks in common but set up unique environments. This will have the following benefits in my view:

1. It will be easy to maintain the templates, and we won't have to worry about the inline scripts breaking YAML.
2. It will allow the reuse of the scripts rather than copying and pasting scripts from one template to another.
3. Maintaining shell scripts outside YAML (in their own files) would allow better quality control of the scripts (e.g., running ShellCheck against the scripts, etc.).

Something similar to the following:

provision:
  - mode: system
    script:
      path: ./scripts/001-bootstrap.sh

Thanks in advance. 🙏

[afbjorklund]

It will need a slightly different syntax, since "script" is the content of the script.

Like:

provision:
  - mode: system
    script: ""
    path: ./scripts/001-bootstrap.sh

The main complexity is that the script path needs to be available in the instance.

With the Ansible playbooks, they are copied over by ansible-playbook command

---

Some templates are using external scripts today, but then they are downloaded:

    curl -fsSL https://get.docker.com | sh

            curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="server --write-kubeconfig-mode 644" sh -

Another approach is to template the creation of the yaml files, something like jinja2.

[Ranjandas]

@afbjorklund, Thank you so much for explaining. Btw, can't limactl slurp the script's content from .path and safely inject it into .script at launch?

[afbjorklund]

Yes, there was some talk about an "include" functionality. But nothing decided yet. Even the simple . ($PWD) has problems.

[afbjorklund]

Added a PR #2442 - note that the paths need to remain available at runtime, they are not copied into the instance directory

[afbjorklund]

• Suggestion: allow using "." in mount location and\or scripts #893

[afbjorklund]

Note that you can still run shellcheck if you want, by using yq to extract the scripts from the yaml.

yq .provision.[].script

EDIT: However, it will complain about the go template strings - I guess those need expanding first...

mkdir -p {{.Home}}/.kube
         ^-- SC1083: This { is literal. Check expression (missing ;/\n?) or quote it.
          ^-- SC1083: This { is literal. Check expression (missing ;/\n?) or quote it.
                ^-- SC1083: This } is literal. Check expression (missing ;/\n?) or quote it.
                 ^-- SC1083: This } is literal. Check expression (missing ;/\n?) or quote it.

[Ranjandas]

Thank you @afbjorklund. Yes, I have been doing it this way. But more than running shell check ad-hoc, the authoring experience of shell script is what I was looking to improve (use of an IDE/EDITOR with syntax highlighting, shellcheck addon etc).