Builtin function in an "existing package"

[ricleal-fugue]

Hi all,

So I have rego package called pack where I have few functions.

I created a builtin function as if it was in this package:

var resourcesBuiltin = &ast.Builtin{
	Name:     "pack.resources",
	Decl:     types.NewFunction(types.Args(types.S), types.A),
	Relation: true,
}

I have a few modules that use this builtin function.
When I compile these modules with the builtin created:

	compiler := ast.NewCompiler().WithBuiltins(map[string]*ast.Builtin{
		resourcesBuiltin.Name: resourcesBuiltin,
	})
	compiler.Compile(mods)
	if compiler.Failed() {
		return nil, compiler.Errors
	}

The compiler fails with the message:

Code:"rego_type_error"
Message:"undefined function data.pack.resources"

Is this normal? The builtins have to be declared in a new package?
Thanks

[anderseknert]

Built-in functions aren't bound to a package. I'm a little surprised by the error message though, as I wouldn't have expected the name to be treated as any other (i.e. without consideration for the package it was in), and this seems to be the case for other built-ins. This works fine, for example:

package object

foo := object.get(input, "bar", null)

How are you referencing that function in your policy?

[ricleal-fugue]

Thanks for the reply.

In the policy that I pass to the compiler I'm just calling it as a regular function:

package pack2.subpack2

import data.pack

(...)

# this a func implemented in `pack`
r = pack.func1("xpto")

# This is a call to my builtin
my_resources = pack.resources("cloud")

(...)

The 2nd call is the one that fails...

[anderseknert]

Thanks for clarifying. The behavior is the same for the provided built-ins:

package foo

import data.object

x = object.get(input, ["x"], null)

1 error occurred: foo.rego:5: rego_type_error: undefined function data.object.get

I.e. the import data.object will make import object into the module, and later references to object will assume that's what is asked for... I'm honestly not sure about the expected behavior here, but I'd suggest renaming your custom built-in to not conflict with the name of your imported package, alternatively you could us as to rename the import, like:

package foo

import data.object as obj

x = object.get(input, ["x"], null)

The custom built-in function is not bound to a package, so IMHO it makes sense to not name it as if it was.

[ricleal-fugue]

Thanks for the reply and clarifying the issue.
I will name my built-in differently.
Thanks again.