| // Copyright 2021 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 session defines API for the session storage. |
| package session |
| |
| import ( |
| "context" |
| "crypto/rand" |
| "encoding/base64" |
| "fmt" |
| |
| "go.chromium.org/luci/server/encryptedcookies/session/sessionpb" |
| ) |
| |
| // ID identifies a session. |
| type ID []byte |
| |
| // String is used to format the ID for logging. |
| func (id ID) String() string { |
| return base64.RawStdEncoding.EncodeToString(id) |
| } |
| |
| // GenerateID generates a new random session ID or panics if there's not enough |
| // entropy. |
| func GenerateID() ID { |
| id := make([]byte, 20) |
| if _, err := rand.Read(id); err != nil { |
| panic(fmt.Sprintf("failed to generate session ID: %s", err)) |
| } |
| return id |
| } |
| |
| // Store is a persistent transactional-capable storage of user sessions. |
| // |
| // Session IDs are assumed to be generated by GenerateID, i.e. be high-entropy |
| // random blobs. |
| type Store interface { |
| // FetchSession fetches an existing session with the given ID. |
| // |
| // Returns (nil, nil) if there's no such session. All errors are transient. |
| FetchSession(ctx context.Context, id ID) (*sessionpb.Session, error) |
| |
| // UpdateSession transactionally updates or creates a session. |
| // |
| // If fetches the session, calls the callback to mutate it, and stores the |
| // result. If it is a new session, the callback receives an empty proto. |
| // |
| // The callback may be called multiple times in case the transaction is |
| // retried. Errors from callbacks are returned as is. All other errors are |
| // transient. |
| UpdateSession(ctx context.Context, id ID, cb func(*sessionpb.Session) error) error |
| } |