would you consider adding Kotlin scripts for Hooks?

Hi @Giuseppe Barbieri, it's not on the roadmap for now. Could you please open a issue?

sure, no problem

You are welcome to contribute the code @Giuseppe Barbieri

I'd love, but I don't even know where to start from, I'd need some inputs for that

Not something that I tested, but it looks like a valid alternative you can start using now - https://ktor.io/ and use lakefs hooks to trigger your code

this shall be triggered via a webhook, right?

yes, you can use https://docs.lakefs.io/howto/hooks/webhooks.html or Lua if you need more control

sorry, but I'm having issues trying to understand where the logic is executed let's look for example at this example, that ensures only parquet files are allowed on a merge on

master

, it will generate a POST to

http://<host:port>/webhooks/format

like

{
  "event_type": "pre-merge",
  "event_time": "..",
  "action_name": "ParquetOnlyInProduction",
  "hook_id": "production_format_validator",
  "repository_id": "repo1",
  "branch_id": "branch1",
  "source_ref": "branch1",
  "commit_message": "commit message",
  "committer": "committer",
  "commit_metadata": {
    "key": "value"
  }
}

the server receive that POST and then? How can it check if there are only parquet files?

Good example. The hook implementation uses lakefs API to list the changes and block the change as needed.

could you elaborate?

https://github.com/treeverse/lakeFS-hooks/blob/01a70e297bb291068f23c0b2367711b5973b2eb8/server.py#L27 the link to the example, check the web hook "format" handler. it uses lakefs API to query the data it validates.