func ExampleQuery() {
// 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 module with rules that produce documents that we will query below.
module, err := ast.ParseModule("my_module.rego", `
package opa.example
p[x] :- q[x], not r[x]
q[y] :- a = [1,2,3], y = a[_]
r[z] :- b = [2,4], z = b[_]
`)
mods := map[string]*ast.Module{
"my_module": module,
}
if compiler.Compile(mods); compiler.Failed() {
fmt.Println(compiler.Errors)
}
if err != nil {
// Handle error.
}
// Instantiate the policy engine's storage layer.
store := storage.New(storage.InMemoryConfig())
// 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 query parameters. In this case, there are no additional documents
// required by the policy so the request is nil.
var request ast.Value
params := topdown.NewQueryParams(ctx, compiler, store, txn, request, ast.MustParseRef("data.opa.example.p"))
// Execute the query against "p".
v1, err1 := topdown.Query(params)
// Inspect the result.
fmt.Println("v1:", v1[0].Result)
fmt.Println("err1:", err1)
// Output:
// v1: [1 3]
// err1: <nil>
}
// loadRequest returns the request defined in the REPL. The REPL loads the
// request from the data.repl.request document.
func (r *REPL) loadRequest(ctx context.Context, compiler *ast.Compiler) (ast.Value, error) {
params := topdown.NewQueryParams(ctx, compiler, r.store, r.txn, nil, ast.MustParseRef("data.repl.request"))
result, err := topdown.Query(params)
if err != nil {
return nil, err
}
if result.Undefined() {
return nil, nil
}
return ast.InterfaceToValue(result[0].Result)
}
func TestScheduler(t *testing.T) {
params := setup(t, "data_10nodes_30pods.json")
defer params.Store.Close(params.Context, params.Transaction)
qrs, err := topdown.Query(params)
if err != nil {
t.Fatal("unexpected error:", err)
}
ws := qrs[0].Result.(map[string]interface{})
if len(ws) != 10 {
t.Fatal("unexpected query result:", qrs)
}
for n, w := range ws {
if fmt.Sprint(w) != "5.01388889" {
t.Fatalf("unexpected weight for: %v: %v\n\nDumping all weights:\n\n%v\n", n, w, qrs)
}
}
}
func runSchedulerBenchmark(b *testing.B, nodes int, pods int) {
params := setupBenchmark(nodes, pods)
defer params.Store.Close(params.Context, params.Transaction)
b.ResetTimer()
for i := 0; i < b.N; i++ {
qrs, err := topdown.Query(params)
if err != nil {
b.Fatal("unexpected error:", err)
}
ws := qrs[0].Result.(map[string]interface{})
if len(ws) != nodes {
b.Fatal("unexpected query result:", qrs)
}
for n, w := range ws {
if fmt.Sprint(w) != "5.01388889" {
b.Fatalf("unexpected weight for: %v: %v\n\nDumping all weights:\n\n%v\n", n, w, qrs)
}
}
}
}
func executeQuery(data string, compiler *ast.Compiler, tracer topdown.Tracer) {
topdown.ResetQueryIDs()
d := map[string]interface{}{}
if len(data) > 0 {
if err := util.UnmarshalJSON([]byte(data), &d); err != nil {
panic(err)
}
}
ctx := context.Background()
store := storage.New(storage.InMemoryWithJSONConfig(d))
txn := storage.NewTransactionOrDie(ctx, store)
defer store.Close(ctx, txn)
params := topdown.NewQueryParams(ctx, compiler, store, txn, nil, ast.MustParseRef("data.test.p"))
params.Tracer = tracer
_, err := topdown.Query(params)
if err != nil {
panic(err)
}
}
func (s *Server) v1DataGet(w http.ResponseWriter, r *http.Request) {
// Gather request parameters.
ctx := r.Context()
vars := mux.Vars(r)
path := stringPathToDataRef(vars["path"])
pretty := getPretty(r.URL.Query()["pretty"])
explainMode := getExplain(r.URL.Query()["explain"])
request, nonGround, err := parseRequest(r.URL.Query()[ParamRequestV1])
if err != nil {
handleError(w, 400, err)
return
}
if nonGround && explainMode != explainOffV1 {
handleError(w, 400, fmt.Errorf("explanations with non-ground request values not supported"))
return
}
// Prepare for query.
txn, err := s.store.NewTransaction(ctx)
if err != nil {
handleErrorAuto(w, err)
return
}
defer s.store.Close(ctx, txn)
compiler := s.Compiler()
params := topdown.NewQueryParams(ctx, compiler, s.store, txn, request, path)
var buf *topdown.BufferTracer
if explainMode != explainOffV1 {
buf = topdown.NewBufferTracer()
params.Tracer = buf
}
// Execute query.
qrs, err := topdown.Query(params)
// Handle results.
if err != nil {
handleErrorAuto(w, err)
return
}
if qrs.Undefined() {
if explainMode == explainFullV1 {
handleResponseJSON(w, 404, newTraceV1(*buf), pretty)
} else {
handleResponse(w, 404, nil)
}
return
}
if nonGround {
handleResponseJSON(w, 200, newQueryResultSetV1(qrs), pretty)
return
}
result := qrs[0].Result
switch explainMode {
case explainOffV1:
handleResponseJSON(w, 200, result, pretty)
case explainFullV1:
handleResponseJSON(w, 200, newTraceV1(*buf), pretty)
case explainTruthV1:
answer, err := explain.Truth(compiler, *buf)
if err != nil {
handleErrorAuto(w, err)
return
}
handleResponseJSON(w, 200, newTraceV1(answer), pretty)
}
}