feat: add support to run pre/post scripts

[imobachgs]

This is the first implementation of pre/post-installation scripts. They are not as capable as their AutoYaST counterparts, but the idea is to evolve them in the future.

Specifying a script

Warning

JSON does not support multiline values (a.k.a. blocks) but Jsonnet does it. Perhaps we should consider using Jsonnet in the agama config edit command.

{
  scripts: {
    pre: [
      {
         name: "say-hi",
         body: |||
           #!/bin/bash
           echo "before starting the installation"
         |||
      }
    ]
  }
}

Note

What about having a plain list where each script has a type (or group) like pre, post, etc.?

When scripts get executed

• Pre-scripts: when loading a profile. We plan to do some improvements to support the single-product case properly.
• Post-scripts: after the installation.

Implementation details

The scripting support is written in Rust and does not use the YaST scripts code anymore. We will rewrite the Manager in Rust (at least the Agama-specific part) in the future, and the scripting support will be part of that.

Future

Agama scripts will gain additional features soon:

• Running in a chroot.
• Better error handling if the shebang line is not present.
• Running after the first boot.

Pending tasks

• Extend the JSON schema
• Copy the resulting files to the installed system
• Add some logging
• Clean-up the old scripts when reloading a profile

[coveralls]

Pull Request Test Coverage Report for Build 11368553812

Details

• 47 of 126 (37.3%) changed or added relevant lines in 7 files are covered.
• 4 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.2%) to 70.862%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
rust/agama-server/src/web.rs	0	1	0.0%
rust/agama-lib/src/store.rs	0	4	0.0%
rust/agama-lib/src/scripts/model.rs	32	37	86.49%
rust/agama-lib/src/scripts/client.rs	0	10	0.0%
rust/agama-server/src/scripts/web.rs	0	27	0.0%
rust/agama-lib/src/scripts/store.rs	0	32	0.0%

Files with Coverage Reduction	New Missed Lines	%
rust/agama-lib/src/store.rs	1	0.0%
rust/agama-server/src/web.rs	1	0.0%
service/lib/agama/storage/finisher.rb	2	98.33%

Totals
Change from base Build 11364775644:	-0.2%
Covered Lines:	16126
Relevant Lines:	22757

---

💛 - Coveralls

[lslezak]

Just some minor comments, looks good to me.

[lslezak]

We should document that the user scripts are copied to the logs in the installed system. The user scripts might contain sensitive data (passwords, tokens, keys, certificates,...) and the users should be aware of this when attaching the logs to bugzilla or sending via email.

[imobachgs]

We could move them to a different place (in AutoYaST they are copied to /var/adm/autoinstall.

[lslezak]

Um, when exactly? Nothing done yet?

I mean later we might add a "post-partitioning" script so it should be clean whether at this point something is already done by Agama or the system has not been touched yet.

[imobachgs]

Before the post-partitioning. I can improve the description.

[imobachgs]

They were expected to be used to modify the profile, but I am not sure whether we should implement that behavior. Or perhaps to activate some hardware.

[jreidinger]

Hmm, I am not sure I like it. Separation of load and store is understandable, but why it runs pre script when store? This looks kind of unexpected.

[imobachgs]

Well, that's a good question. When would you run the pre-script? In the future we should be able to run the script when loading the profile (to modify it in-place). But we can postpone it until you click the "install" button. I guess we will need to do more adjustments in this area.

[jreidinger]

I would do it one level up, when you load profile, then run any pre script it will find....but e.g. not before you validate that profile.

[imobachgs]

No, no, question was not where in the code, but when. Given that the pre scripts does not support changing the profile yet, I am not sure there is a use case for them right now.

Perhaps you want to enable something, but then pre scripts might need to run the probing, but probing happens only once in Agama by now (and for single product scenarios it happens too early).