| // Copyright 2017 The LUCI Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package policy |
| |
| import ( |
| "bytes" |
| "encoding/gob" |
| "fmt" |
| "sort" |
| |
| "google.golang.org/protobuf/proto" |
| "google.golang.org/protobuf/reflect/protoreflect" |
| "google.golang.org/protobuf/reflect/protoregistry" |
| ) |
| |
| // ConfigBundle is a bunch of related parsed text proto files. |
| // |
| // For example, it may be a main top-level config and a bunch of include files |
| // it references. |
| // |
| // Keys are paths, values are corresponding proto messages. Users are supposed |
| // to know themselves what concrete proto types correspond to what paths. |
| type ConfigBundle map[string]proto.Message |
| |
| // blobWithType is underlying type of a slice we gob-serialize in serialize(). |
| type blobWithType struct { |
| Path string // the path the config was fetched from |
| Kind string // proto message kind, to know how to deserialize |
| Blob []byte // proto message, binary serialization |
| } |
| |
| // serializeBundle deterministically converts ConfigBundle into a byte blob. |
| // |
| // The byte blob references proto message names to know how to deserialize them |
| // later. |
| func serializeBundle(b ConfigBundle) ([]byte, error) { |
| keys := make([]string, 0, len(b)) |
| for k := range b { |
| keys = append(keys, k) |
| } |
| sort.Strings(keys) |
| |
| items := make([]blobWithType, 0, len(b)) |
| for _, k := range keys { |
| v := b[k] |
| if v == nil { |
| return nil, fmt.Errorf("no config body in %q", k) |
| } |
| blob, err := proto.Marshal(v) |
| if err != nil { |
| return nil, err |
| } |
| items = append(items, blobWithType{ |
| Path: k, |
| Kind: string(proto.MessageName(v)), |
| Blob: blob, |
| }) |
| } |
| |
| out := bytes.Buffer{} |
| if err := gob.NewEncoder(&out).Encode(items); err != nil { |
| return nil, err |
| } |
| return out.Bytes(), nil |
| } |
| |
| // deserialize parses the serialized ConfigBundle. |
| // |
| // It skips configs with proto types no longer registered in the proto lib |
| // registry. It returns them unparsed in 'unknown' slice. |
| // |
| // Returns an error if some known proto message can't be deserialized. |
| func deserializeBundle(blob []byte) (b ConfigBundle, unknown []blobWithType, err error) { |
| items := []blobWithType{} |
| if err := gob.NewDecoder(bytes.NewReader(blob)).Decode(&items); err != nil { |
| return nil, nil, err |
| } |
| |
| b = make(ConfigBundle, len(items)) |
| for _, item := range items { |
| typ, err := protoregistry.GlobalTypes.FindMessageByName(protoreflect.FullName(item.Kind)) |
| if err != nil { |
| unknown = append(unknown, item) |
| continue |
| } |
| msg := typ.New().Interface() |
| if err := proto.Unmarshal(item.Blob, msg); err != nil { |
| return nil, nil, err |
| } |
| b[item.Path] = msg |
| } |
| |
| return b, unknown, nil |
| } |