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)
}
}
}
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>
}