Add Jsonnet support

[qwerty287]

Jsonnet is a templating language for JSON.

Example for a pipeline config (running with local backend):

{
    pipeline: [
        {
            name: "bash-step",
            image: "bash",
            commands: ["echo Hello " + self.image + "!"],
        },
        self.pipeline[0] { name: "zsh-step", image: "zsh" },
    ]
}

which is evaluated into:

{
   "pipeline": [
      {
         "commands": [
            "echo Hello bash!"
         ],
         "image": "bash",
         "name": "bash-step"
      },
      {
         "commands": [
            "echo Hello zsh!"
         ],
         "image": "zsh",
         "name": "zsh-step"
      }
   ]
}

[6543]

I'm against it and for a global "compile" step that is plugin based ..

@anbraten ?

[6543]

as per comment - we need to chat about this clearly

[lafriks]

I also agree that this should be made plugable at least by clear interface than they could be either builtin or external plugins

[qwerty287]

Closing as per discussion

[6543]

still thanks for looking into it :)

[6543]

-> #1400