Reading pkl objects remotely

[fhalde]

Hello,

Let's say our platform has defined some standard Pkl class Foo to represent some entity in our platform named Foo

class Foo {
 name: String
}

Is it possible to write a Pkl configuration that reads these Foo objects exposed over an API ?

myfoo: Foo = read("http://localhost:9092/foo/1")

We are mainly unsure what should be the return format of the endpoint

• JSON
• Pcf Rendered Pkl object

I'm open for suggestions.

read("http://localhost:9092/foo/1")
=> new Resource { uri = "file:stream.pkl"; text = "bird {\n hello = 1\n}\n"; base64 = "YmlyZCB7CiBoZWxsbyA9IDEKfQo=" }

Could this text be parsed into a Pkl class instance?

[fhalde]

Alternatively, would it make sense to import "http://localhost:9092/foo/1" ?

[StefMa]

You can put your base pkl file somewhere on the internet and then just import via https.
See also https://pkl-lang.org/main/current/language-reference/index.html#import-module

Is that what you're looking for? 🤔

[fhalde]

ya i'm thinking in the same lines

1. master.pkl => declares all the known types in the platform.
2. users configure instances of all the known types as .pkl files and make these pkl files addressable over an endpoint.
3. application writers, import these user generated pkl files using their well-known-uri to produce their final app configuration.

[bioball]

Both import and read are able to interact with HTTPS endpoints. So, both of these work, assuming that the remote resource exists:

import "https://example.com/path/to/remote/module.pkl"

remoteResource: Resource = read("https://www.example.com/path/to/remote/resource.json")

Note that resources fetch over HTTP(S) do not get cached across evaluations. So, calling Pkl will result in an HTTP call every time.
Additionally, to ensure reproducible output within a single evaluation, Pkl will cache the result of any import/read by its URI per evaluator session.