From 17803266d42f48c70a78b8d1fe7c388dc8f00214 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@rwth-aachen.de>
Date: Tue, 27 Sep 2016 16:12:35 +0200
Subject: [PATCH] repairChecker: Yjs is now able to detect incorrect states
that happen when messages get lost. When Yjs is in an incorrect state it
repairs itself and syncs again
---
src/Connector.js | 10 ++++++++++
src/Database.js | 38 ++++++++++++++++++++++++++++++++++++++
src/SpecHelper.js | 3 ++-
3 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/src/Connector.js b/src/Connector.js
index 7e34534e..61e0972d 100644
--- a/src/Connector.js
+++ b/src/Connector.js
@@ -66,6 +66,16 @@ module.exports = function (Y/* :any */) {
this.whenSyncedListeners = []
return this.y.db.stopGarbageCollector()
}
+ repair () {
+ console.info('Repairing the state of Yjs. This can happen if messages get lost, and Yjs detects that something is wrong. If this happens often, please report an issue here: https://github.com/y-js/yjs/issues')
+ for (var name in this.connections) {
+ this.connections[name].isSynced = false
+ }
+ this.isSynced = false
+ this.currentSyncTarget = null
+ this.broadcastedHB = false
+ this.findNextSyncTarget()
+ }
setUserId (userId) {
if (this.userId == null) {
this.userId = userId
diff --git a/src/Database.js b/src/Database.js
index d1aca8fe..dbbec5e7 100644
--- a/src/Database.js
+++ b/src/Database.js
@@ -112,6 +112,41 @@ module.exports = function (Y /* :any */) {
if (this.gcTimeout > 0) {
garbageCollect()
}
+ this.repairCheckInterval = !opts.repairCheckInterval ? 6000 : opts.repairCheckInterval
+ this.opsReceivedTimestamp = new Date()
+ this.startRepairCheck()
+ }
+ startRepairCheck () {
+ var os = this
+ if (this.repairCheckInterval > 0) {
+ this.repairCheckIntervalHandler = setInterval(function repairOnMissingOperations () {
+ /*
+ Case 1. No ops have been received in a while (new Date() - os.opsReceivedTimestamp > os.repairCheckInterval)
+ - 1.1 os.listenersById is empty. Then the state was correct the whole time. -> Nothing to do (nor to update)
+ - 1.2 os.listenersById is not empty.
+ * Then the state was incorrect for at least {os.repairCheckInterval} seconds.
+ * -> Remove everything in os.listenersById and sync again (connector.repair())
+ Case 2. An op has been received in the last {os.repairCheckInterval } seconds.
+ It is not yet necessary to check for faulty behavior. Everything can still resolve itself. Wait for more messages.
+ If nothing was received for a while and os.listenersById is still not emty, we are in case 1.2
+ -> Do nothing
+
+ Baseline here is: we really only have to catch case 1.2..
+ */
+ if (
+ new Date() - os.opsReceivedTimestamp > os.repairCheckInterval &&
+ Object.keys(os.listenersById).length > 0 // os.listenersById is not empty
+ ) {
+ // haven't received operations for over {os.repairCheckInterval} seconds, resend state vector
+ os.listenersById = {}
+ os.opsReceivedTimestamp = new Date() // update so you don't send repair several times in a row
+ os.y.connector.repair()
+ }
+ }, this.repairCheckInterval)
+ }
+ }
+ stopRepairCheck () {
+ clearInterval(this.repairCheckIntervalHandler)
}
queueGarbageCollector (id) {
if (this.y.isConnected()) {
@@ -207,6 +242,7 @@ module.exports = function (Y /* :any */) {
* destroy () {
clearInterval(this.gcInterval)
this.gcInterval = null
+ this.stopRepairCheck()
for (var key in this.initializedTypes) {
var type = this.initializedTypes[key]
if (type._destroy != null) {
@@ -246,12 +282,14 @@ module.exports = function (Y /* :any */) {
/*
Apply a list of operations.
+ * we save a timestamp, because we received new operations that could resolve ops in this.listenersById (see this.startRepairCheck)
* get a transaction
* check whether all Struct.*.requiredOps are in the OS
* check if it is an expected op (otherwise wait for it)
* check if was deleted, apply a delete operation after op was applied
*/
apply (ops) {
+ this.opsReceivedTimestamp = new Date()
for (var i = 0; i < ops.length; i++) {
var o = ops[i]
if (o.id == null || o.id[0] !== this.y.connector.userId) {
diff --git a/src/SpecHelper.js b/src/SpecHelper.js
index b06eca07..24eded79 100644
--- a/src/SpecHelper.js
+++ b/src/SpecHelper.js
@@ -337,7 +337,8 @@ g.createUsers = async(function * createUsers (self, numberOfUsers, database, ini
name: database,
namespace: 'User ' + i,
cleanStart: true,
- gcTimeout: -1
+ gcTimeout: -1,
+ repairCheckInterval: -1
},
connector: {
name: 'Test',
--
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