Example #1
0
func TestEventEqual(t *testing.T) {

	a := ast.NewValueMap()
	a.Put(ast.String("foo"), ast.Number("1"))
	b := ast.NewValueMap()
	b.Put(ast.String("foo"), ast.Number("2"))

	tests := []struct {
		a     *Event
		b     *Event
		equal bool
	}{
		{&Event{}, &Event{}, true},
		{&Event{Op: EvalOp}, &Event{Op: EnterOp}, false},
		{&Event{QueryID: 1}, &Event{QueryID: 2}, false},
		{&Event{ParentID: 1}, &Event{ParentID: 2}, false},
		{&Event{Node: ast.MustParseBody("true")}, &Event{Node: ast.MustParseBody("false")}, false},
		{&Event{Node: ast.MustParseBody("true")[0]}, &Event{Node: ast.MustParseBody("false")[0]}, false},
		{&Event{Node: ast.MustParseRule("p :- true")}, &Event{Node: ast.MustParseRule("p :- false")}, false},
		{&Event{Node: "foo"}, &Event{Node: "foo"}, false}, // test some unsupported node type
	}

	for _, tc := range tests {
		if tc.a.Equal(tc.b) != tc.equal {
			var s string
			if tc.equal {
				s = "=="
			} else {
				s = "!="
			}
			t.Errorf("Expected %v %v %v", tc.a, s, tc.b)
		}
	}

}
Example #2
0
func ExampleEval() {
	// Initialize context for the example. Normally the caller would obtain the
	// context from an input parameter or instantiate their own.
	ctx := context.Background()

	compiler := ast.NewCompiler()

	// Define a dummy query and some data that the query will execute against.
	query, err := compiler.QueryCompiler().Compile(ast.MustParseBody("data.a[_] = x, x >= 2"))
	if err != nil {
		// Handle error.
	}

	var data map[string]interface{}

	// OPA uses Go's standard JSON library but assumes that numbers have been
	// decoded as json.Number instead of float64. You MUST decode with UseNumber
	// enabled.
	decoder := json.NewDecoder(bytes.NewBufferString(`{"a": [1,2,3,4]}`))
	decoder.UseNumber()

	if err := decoder.Decode(&data); err != nil {
		// Handle error.
	}

	// Instantiate the policy engine's storage layer.
	store := storage.New(storage.InMemoryWithJSONConfig(data))

	// Create a new transaction. Transactions allow the policy engine to
	// evaluate the query over a consistent snapshot fo the storage layer.
	txn, err := store.NewTransaction(ctx)
	if err != nil {
		// Handle error.
	}

	defer store.Close(ctx, txn)

	// Prepare the evaluation parameters. Evaluation executes against the policy
	// engine's storage. In this case, we seed the storage with a single array
	// of number. Other parameters such as the request, tracing configuration,
	// etc. can be set on the Topdown object.
	t := topdown.New(ctx, query, compiler, store, txn)

	result := []interface{}{}

	// Execute the query and provide a callbakc function to accumulate the results.
	err = topdown.Eval(t, func(t *topdown.Topdown) error {

		// Each variable in the query will have an associated "binding" in the context.
		x := t.Binding(ast.Var("x"))

		// The bindings are ast.Value types so we will convert to a native Go value here.
		v, err := topdown.ValueToInterface(x, t)
		if err != nil {
			return err
		}

		result = append(result, v)
		return nil
	})

	// Inspect the query result.
	fmt.Println("result:", result)
	fmt.Println("err:", err)

	// Output:
	// result: [2 3 4]
	// err: <nil>
}