Testing an OPA builtin with a rego query

1. Set up your main.go to be the following

func main() {
	logLevel := &slog.LevelVar{}
	logLevel.Set(slog.LevelDebug)

	opts := &slog.HandlerOptions{
		Level: logLevel,
	}
	logger := slog.New(slog.NewJSONHandler(os.Stdout, opts))

	slog.SetDefault(logger)

	subjectmappingbuiltin.JQBuiltin()

	if err := cmd.RootCommand.Execute(); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

2. Build the executable

cd service
go build -o opa++

3. Create an example rego file

package sample

my_json = {
  "testing1": {
    "testing2": {
      "testing3": ["helloworld"]
    }
  }
}
req = ".testing1.testing2.testing3[]"

res := jq.evaluate(my_json, req)

4. Perform the query

./opa++ eval -d example.rego 'data.sample.res'