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Add Sync3 WIP

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Kegan Dougal 2021-11-26 11:52:24 +00:00
parent 737d37326a
commit 74195059cf
2 changed files with 452 additions and 24 deletions
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src/matrix/Sync3.ts Normal file
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/*
Copyright 2021 The Matrix.org Foundation C.I.C.
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.
*/
import { ObservableValue } from "../observable/ObservableValue";
import { HomeServerApi } from "./net/HomeServerApi.js";
import { HomeServerRequest } from "./net/HomeServerRequest.js";
import { Storage } from "./storage/idb/Storage";
import { Session } from "./Session";
import { ILogger } from "../logging/types";
/*
* This file contains the logic to perform sync v3 requests and massage the response into a format
* which Hydrogen will accept. If you're reading this then you probably have the unfortunate job
* of merging the sync-v3 branch into mainline Hydrogen. There will be copious comments in this file
* to guide the reader to explain the "why?" of this code - some assumptions made as of this writing
* may no longer be valid. Use your judgement. To that end, this work is based on the following
* version of the sync v3 server: https://github.com/matrix-org/sync-v3/blob/398fc1ec6c67226b7817844074f7c51c3bcfa454/api.md
* Please read that document which explains how Sync v3 works as the comments in this file will not
* repeat content in that link.
*/
// sync v2 code has this so we probably want something similar, though v3 has no concept of a catchup
// sync hence it isn't here.
export enum SyncStatus {
InitialSync, // valid: on startup until the first response. Request has no ?pos=
Syncing, // valid: after the first response. Requests have a ?pos=
Stopped, // valid: when code explicitly calls stop()
};
// Request types are below: See api.md for what these fields mean.
interface Sync3List {
rooms: number[][];
timeline_limit?: number;
required_state?: string[][];
sort?: string[];
};
interface RoomSubscriptionRequest {
timeline_limit?: number;
required_state?: string[][];
};
type RoomSubscriptionsRequest = {
[roomId: string]: RoomSubscriptionRequest
};
interface Sync3RequestBody {
session_id: string;
lists: Sync3List[];
room_subscriptions?: RoomSubscriptionsRequest;
};
// Response types are below: See api.md for what these fields mean.
// A sync v3 response body from the API
interface Sync3Response {
room_subscriptions: RoomSubscriptions;
ops: Op[];
counts: number[];
pos: number;
};
interface Op {
list: number;
op: string;
range?: number[]; // only valid for SYNC, INVALIDATE
rooms?: RoomResponse[]; // only valid for SYNC, INVALIDATE
index?: number; // only valid for INSERT, UPDATE, DELETE
room?: RoomResponse // only valid for INSERT, UPDATE
};
type RoomSubscriptions = {
[roomId: string]: RoomResponse
};
interface RoomResponse {
room_id: string;
name: string;
required_state: any[];
timeline: any[];
notification_count: number;
highlight_count: number;
};
type IndexToRoomId = {
[index: string]: string;
};
export class Sync3 {
private hsApi: HomeServerApi;
private logger: ILogger;
private session: Session;
private storage: Storage;
private currentRequest?: HomeServerRequest;
// sync v3 specific: contains the sliding window ranges to request
private ranges: number[][];
private roomIndexToRoomId: IndexToRoomId;
public error?: any;
public status: ObservableValue<SyncStatus>;
// same params as sync v2
constructor(hsApi: HomeServerApi, session: Session, storage: Storage, logger: ILogger) {
this.hsApi = hsApi;
this.logger = logger;
this.session = session;
this.storage = storage;
this.currentRequest = null;
this.status = new ObservableValue(SyncStatus.Stopped);
this.error = null;
// Hydrogen only has 1 list currently (no DM section) so we only need 1 range
this.ranges = [[0, 99]];
this.roomIndexToRoomId = {};
}
// Start syncing. Probably call this at startup once you have an access_token.
// If we're already syncing, this does nothing.
start(): void {
if (this.status.get() !== SyncStatus.Stopped) {
return;
}
this.error = null;
this.status.set(SyncStatus.InitialSync);
this.syncLoop(undefined);
}
// The purpose of this function is to do repeated /sync calls and call processResponse. It doesn't
// know or care how to handle the response, it only cares about the position and retries.
private async syncLoop(pos?: number) {
// In sync v2 a user can have many devices and each device has a single access token.
// In sync v3 it's the same but IN ADDITION a single device can have many sessions.
// This exists to fix to-device msgs being deleted prematurely caused by implicit ACKs.
// Ergo, we need to specify a session ID when we start and provide it on all our requests.
const sessionId = new Date().getTime() + "";
// Set this too low and we'll do many more needless sync requests which consume bandwidth when there's no traffic.
// Set this too high and intermediate proxies may knife the request causing failed requests.
const timeoutSecs = 30;
// track the number of times we've failed to work out how long to wait between requests
let backoffCounter = 0;
while (this.status.get() !== SyncStatus.Stopped) {
let isFirstSync = this.status.get() === SyncStatus.InitialSync;
const list: Sync3List = {
rooms: this.ranges, // always provide the sliding window ranges
};
if (isFirstSync) {
// add in sticky params, these are set once (initially) and then can be omitted and
// the server will remember them (hence 'sticky').
list.sort = ["by_highlight_count", "by_notification_count", "by_recency"];
list.timeline_limit = 20;
list.required_state = [
["m.room.avatar", ""],
]
}
const requestBody: Sync3RequestBody = {
session_id: sessionId,
lists: [list],
};
try {
await sleep(100);
let resp: Sync3Response;
this.currentRequest = await this.hsApi.sync3(requestBody, pos);
resp = await this.currentRequest.response();
backoffCounter = 0;
// we have to wait for some parts of the response to be saved to disk before we can go on
// hence the await.
await this.processResponse(resp);
// increment our position to tell the server we got everything, similar to using ?since= in v2
pos = resp.pos;
if (isFirstSync) {
this.status.set(SyncStatus.Syncing);
}
} catch (err) {
// we can be aborted if the ranges change and we need to re-request
if (err.name === "AbortError") {
// we can also be aborted if we are explicitly stopped, in which case bail out.
if (this.status.get() == SyncStatus.Stopped) {
return;
}
continue;
}
// TODO: if HTTP 401 then log the user out
// if we're here then another error happened like they lost connectivity or the server
// got overloaded. Back off exponentially: 2>4>8>16>32s. Cap at 32s (2^5)
backoffCounter += 1;
if (backoffCounter > 5) {
backoffCounter = 5;
}
const secs = Math.pow(2, backoffCounter);
console.log(`v3 /sync failed, backing off for ${secs}s`)
await sleep(secs * 1000);
}
}
}
// TODO: Handle room updates
// TODO: atomically swap indexToRoom
// The purpose of this function is process the /sync response and atomically update sync state.
private async processResponse(resp: Sync3Response) {
console.log(resp);
let { indexToRoom, updates } = this.processOps(resp.ops);
// process the room updates: new rooms, new timeline events, updated room names, that sort of thing.
this.prepareResponse(updates);
/*
try {
await log.wrap("prepare", log => this._prepareSync(sessionState, roomStates, response, log));
await log.wrap("afterPrepareSync", log => Promise.all(roomStates.map(rs => {
return rs.room.afterPrepareSync(rs.preparation, log);
})));
await log.wrap("write", async log => this._writeSync(
sessionState, inviteStates, roomStates, archivedRoomStates,
response, syncFilterId, isInitialSync, log));
} finally {
sessionState.dispose();
}
// sync txn comitted, emit updates and apply changes to in-memory state
log.wrap("after", log => this._afterSync(
sessionState, inviteStates, roomStates, archivedRoomStates, log));
*/
// instantly move all the rooms to their new positions
}
// The purpose of this function is to process the response `ops` array by modifying the current
// roooms list. It does this non-destructively to ensure that if we die half way through processing
// we are left in a consistent state. It has a few responsibilities:
// - Keep the index->room_id map up-to-date, this is the sort order for the room list.
// - Remove rooms we are no longer tracking e.g they fell off the sliding window.
// - Add/update rooms which have new events.
// This functions returns the new index->room_id map with updated values along with a bunch of
// RoomUpdates which contain things like new timeline events, required state, etc. Note we don't
// especially handle removed rooms as we don't want to nuke precious data: it's enough to just remove
// them from the map for them to disappear from the list.
private processOps(ops: Op[]): { indexToRoom: IndexToRoomId, updates: RoomResponse[] } {
// copy the index->room_id map. This is assumed to be reasonably cheap as we expect to only have
// up to 200 elements in this map. (first 100 then sliding window 100).
let indexToRoomID = { ...this.roomIndexToRoomId };
let roomUpdates: RoomResponse[] = []; // ordered by when we saw them in the response, earlier ops are earlier
let gapIndex = -1;
for (let i = 0; i < ops.length; i++) {
const op = ops[i];
switch (op.op) {
case "SYNC": {
if (op.range === undefined || op.rooms === undefined) { // required fields
console.error("malformed SYNC:", op);
continue;
}
// e.g [100,199] (inclusive indexes) with an array of 100 rooms
const startIndex = op.range[0];
for (let j = startIndex; j <= op.range[1]; j++) {
const r = op.rooms[j - startIndex];
if (!r) {
break; // we are at the end of list
}
indexToRoomID[j] = r.room_id;
roomUpdates.push(r);
}
break;
}
case "INVALIDATE": {
if (op.range === undefined) { // required fields
console.error("malformed INVALIDATE:", op);
continue;
}
const startIndex = op.range[0];
for (let j = startIndex; j <= op.range[1]; j++) {
delete indexToRoomID[j];
}
break;
}
case "INSERT": {
if (op.index === undefined || op.room === undefined) { // required fields
console.error("malformed INSERT:", op);
continue;
}
if (indexToRoomID[op.index]) {
// there exists a room at this location so we need to shift items out of the way.
if (gapIndex < 0) {
console.error(`cannot INSERT as there is a room already at index ${op.index} there and no gap`);
continue;
}
// 0,1,2,3 index
// [A,B,C,D]
// DEL 3
// [A,B,C,_]
// INSERT E 0
// [E,A,B,C]
// gapIndex=3, op.index=0
if (gapIndex > op.index) {
// the gap is further down the list, shift every element to the right
// starting at the gap so we can just shift each element in turn:
// [A,B,C,_] gapIndex=3, op.index=0
// [A,B,C,C] i=3
// [A,B,B,C] i=2
// [A,A,B,C] i=1
// Terminate. We'll assign into op.index next.
for (let j = gapIndex; j > op.index; j--) {
if (indexInRange(this.ranges, j)) {
indexToRoomID[j] = indexToRoomID[j - 1];
}
}
} else if (gapIndex < op.index) {
// the gap is further up the list, shift every element to the left
// starting at the gap so we can just shift each element in turn
for (let j = gapIndex; j < op.index; j++) {
if (indexInRange(this.ranges, j)) {
indexToRoomID[j] = indexToRoomID[j + 1];
}
}
}
}
// assign to this index
indexToRoomID[op.index] = op.room.room_id;
roomUpdates.push(op.room);
break;
}
case "DELETE": {
if (op.index === undefined) { // required fields
console.error("malformed DELETE:", op);
continue;
}
// Delete the room at this index and remember the new gap. It may be filled in
// a moment by a corresponding INSERT.
delete indexToRoomID[op.index];
gapIndex = op.index;
break;
}
case "UPDATE": {
if (op.index === undefined || op.room === undefined) { // required fields
console.error("malformed UPDATE:", op);
continue;
}
roomUpdates.push(op.room);
break;
}
default:
console.error("skipping unknown op: ", op.op);
}
}
return {
indexToRoom: indexToRoomID,
updates: roomUpdates,
};
}
private async prepareResponse(updates: RoomResponse[]) {
/*
// IF WE HAVE TO-DEVICE MSGS THEN this.session.obtainSyncLock(response) (which checks response.to_device.events)
const prepareTxn = await this.openPrepareSyncTxn();
// IF WE HAVE TO-DEVICE MSGS THEN this.session.prepareSync(syncResponse, lock, txn, log) => {newKeysByRoom}
// purpose: add any rooms with new keys but no sync response to the list of rooms to be synced
await Promise.all(updates.map(async (roomResponse) => {
let storedRoom = this.session.rooms.get(roomResponse.room_id);
if (!storedRoom) {
storedRoom = this.session.createRoom(roomResponse.room_id);
} else {
// if previously joined and we still have the timeline for it,
// this loads the syncWriter at the correct position to continue writing the timeline
await storedRoom.load(null, prepareTxn, this.logger);
}
return storedRoom.prepareSync(
rs.roomResponse, rs.membership, rs.invite, newKeys, prepareTxn, log)
}));
// This is needed for safari to not throw TransactionInactiveErrors on the syncTxn. See docs/INDEXEDDB.md
await prepareTxn.complete();
await Promise.all(updates.map(rs => {
return rs.room.afterPrepareSync(rs.preparation, log);
})); */
}
stop() {
if (this.status.get() === SyncStatus.Stopped) {
return;
}
this.status.set(SyncStatus.Stopped);
if (this.currentRequest) {
this.currentRequest.abort();
this.currentRequest = null;
}
}
// storage locking shenanigans here
openPrepareSyncTxn() {
const storeNames = this.storage.storeNames;
return this.storage.readTxn([
storeNames.olmSessions,
storeNames.inboundGroupSessions,
// to read fragments when loading sync writer when rejoining archived room
storeNames.timelineFragments,
// to read fragments when loading sync writer when rejoining archived room
// to read events that can now be decrypted
storeNames.timelineEvents,
]);
}
}
const sleep = (ms) => {
return new Promise((resolve) => setTimeout(resolve, ms));
};
// SYNC 0 2 a b c; SYNC 6 8 d e f; DELETE 7; INSERT 0 e;
// 0 1 2 3 4 5 6 7 8
// a b c d e f
// a b c d _ f
// e a b c d f <--- c=3 is wrong as we are not tracking it, ergo we need to see if `i` is in range else drop it
const indexInRange = (ranges, i) => {
let isInRange = false;
ranges.forEach((r) => {
if (r[0] <= i && i <= r[1]) {
isInRange = true;
}
});
return isInRange;
};
export function tests() {
return {
"processOps": assert => {
assert.equal(1, 1);
},
};
}

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src/placeholder-rooms.html
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@ -23,6 +23,7 @@
import {ObservableMap} from "./observable/index.js";
import {History} from "./platform/web/dom/History.js";
import {HomeServerApi} from "./matrix/net/HomeServerApi.js";
import {Sync3} from "./matrix/Sync3";
import {xhrRequest} from "./platform/web/dom/request/xhr.js";
const navigation = new Navigation(() => false);
const rooms = new ObservableMap();
@ -70,7 +71,6 @@
const view = new LeftPanelView(leftPanel);
document.getElementById("session-status").appendChild(view.mount());
document.getElementById("tokensubmit").addEventListener("click", () => {
const accessToken = document.getElementById("tokeninput").value;
const sessionId = new Date().getTime() + "";
@ -79,29 +79,8 @@
accessToken: accessToken,
request: xhrRequest,
});
const loop = async () => {
let pos;
while (true) {
let req = hs.sync3({
session_id: sessionId,
lists: [{
rooms: [ [0,99] ],
// TODO: only send these the first time.
sort: ["by_highlight_count", "by_notification_count", "by_recency"],
timeline_limit: 20,
required_state: [
["m.room.avatar", ""],
]
}],
}, pos, 10);
const resp = await req.response();
console.log(resp);
pos = resp.pos;
await sleep(100);
}
}
loop();
const syncer = new Sync3(hs, null, null, null);
syncer.start();
});
</script>