Rego 1.0.0

Rego

What is Rego?

Rego is a language developed by Open Policy Agent (OPA) for use in defining policies in cloud systems.

We think Rego is a great language, and you can learn more about it from the OPA website. However, it has some limitations. Primarily, the interpreter is only accessible via the command line or a web server. Further, the only option for using the language in-process is via an interface in Go.

The rego-cpp project provides the ability to integrate Rego natively into a wider range of languages. We currrently support C, C++, Rust, Python and, via this package, .NET, and are largely compatible with v1.8.0 of the language. You can learn more about our implementation on our Github page.

Getting Started

Here is an example of how to use the library to execute Rego queries:

using Rego;

var rego = new Interpreter();

// If you provide an object, it will be converted to JSON before
// being added to the state.
var data0 = new Dictionary<string, object>{
    {"one", new Dictionary<string, object>{
        {"bar", "Foo"},
        {"baz", 5},
        {"be", true},
        {"bop", 23.4}}},
    {"two", new Dictionary<string, object>{
        {"bar", "Bar"},
        {"baz", 12.3},
        {"be", false},
        {"bop", 42}}}};
rego.AddData(data0);

// You can also provide JSON directly.
rego.AddDataJson("""
    {
        "three": {
            "bar": "Baz",
            "baz": 15,
            "be": true,
            "bop": 4.23
        }
    }
    """);

var objectsSource = """
    package objects

    rect := {"width": 2, "height": 4}
    cube := {"width": 3, "height": 4, "depth": 5}
    a := 42
    b := false
    c := null
    d := {"a": a, "x": [b, c]}
    index := 1
    shapes := [rect, cube]
    names := ["prod", "smoke1", "dev"]
    sites := [{"name": "prod"}, {"name": names[index]}, {"name": "dev"}]
    e := {
        a: "foo",
        "three": c,
        names[2]: b,
        "four": d,
    }
    f := e["dev"]
    """;
rego.AddModule("objects", objectsSource);

// inputs can be either JSON or Rego, and provided
// as objects (which will be converted to JSON) or as
// text.
rego.SetInputTerm("""
    {
        "a": 10,
        "b": "20",
        "c": 30.0,
        "d": true
    }
    """);

Console.WriteLine(rego.Query("[data.one, input.b, data.objects.sites[1]] = x"));
// Result: {"bindings":{"x":[{"bar":"Foo", "baz":5, "be":true, "bop":23.4}, "20", {"name":"smoke1"}]}}