main.go

package main

import (
	"context"
	"fmt"

	"github.com/open-policy-agent/opa/ast"
	"github.com/open-policy-agent/opa/rego"
)

func main() {

	set := ast.NewTerm(ast.NewSet(ast.StringTerm("hello"), ast.StringTerm("goodbye")))

	// Construct a module containing a rule that generates the set.
	// The set will be located at data.foo.bar.
	module := &ast.Module{Package: ast.MustParsePackage("package foo")}
	module.Rules = append(module.Rules, &ast.Rule{
		Module: module,
		Head: &ast.Head{
			Name:  ast.Var("bar"),
			Value: set,
		},
		Body: ast.NewBody(ast.NewExpr(ast.BooleanTerm(true))),
	})

	// Check if "hello" is in the set.
	r := rego.New(rego.ParsedModule(module), rego.Query(`data.foo.bar["hello"]`))
	rs, err := r.Eval(context.Background())

	fmt.Println(rs)
	fmt.Println(err)

	// Check if "deadbeef" is in the set.
	r = rego.New(rego.ParsedModule(module), rego.Query(`data.foo.bar["deadbeef"]`))
	rs, err = r.Eval(context.Background())

	fmt.Println(rs)
	fmt.Println(err)
}