Wait for homeserver when bridge is first started

src/d2m/discord-client.js

@@ -14,6 +14,8 @@ const {sync} = passthrough
 /** @type {import("./discord-packets")} */
 const discordPackets = sync.require("./discord-packets")
 
+const CONNECTION_DEBUG = false
+
 class DiscordClient {
 	/**
 	 * @param {string} discordToken
@@ -59,15 +61,17 @@ class DiscordClient {
 			})
 		}
 
-		const addEventLogger = (eventName, logName) => {
-			this.cloud.on(eventName, (...args) => {
-				const d = new Date().toISOString().slice(0, 19)
-				console.error(`[${d} Client ${logName}]`, ...args)
-			})
+		if (CONNECTION_DEBUG) {
+			const addEventLogger = (eventName, logName) => {
+				this.cloud.on(eventName, (...args) => {
+					const d = new Date().toISOString().slice(0, 19)
+					console.error(`[${d} Client ${logName}]`, ...args)
+				})
+			}
+			addEventLogger("error", "Error")
+			addEventLogger("disconnected", "Disconnected")
+			addEventLogger("ready", "Ready")
 		}
-		addEventLogger("error", "Error")
-		addEventLogger("disconnected", "Disconnected")
-		addEventLogger("ready", "Ready")
 	}
 }
 

src/d2m/discord-packets.js

@@ -1,12 +1,15 @@
 // @ts-check
 
 const assert = require("assert")
+const {scheduler} = require("timers/promises")
 const passthrough = require("../passthrough")
 const {sync} = passthrough
 
 /** @type {import("../matrix/homeserver-status")} */
 const homeserverStatus = sync.require("../matrix/homeserver-status")
 
+let checkedHomeserver = false
+
 /**
  * @param {import("./discord-client")} client
  * @param {import("cloudstorm").IGatewayMessage} message
@@ -48,6 +51,31 @@ async function onPacket(client, message, listen) {
 
 		if (listen === "full") {
 			try {
+				/*
+					Info about guilds is populated one guild at a time.
+					For m->d bridging to work, the guild needs to be populated, so we need to have GUILD_CREATE for the guild.
+					If we ping the homeserver, it will send us any pending events, so we need to wait for all GUILD_CREATES before we ping.
+					We must attempt a ping because we don't want to try sending missed d->m messages to an offline homeserver.
+					This delay can be removed if ONE of the following is done:
+						1. m->d can queue incoming events until their guild exists in memory
+						2. d->m missed messages can have their errors handled and added to queue, rather than pinging first
+				*/
+				let isMainCharacter = false
+				if (!checkedHomeserver) {
+					checkedHomeserver = true
+					isMainCharacter = true
+					console.log("Warming up guilds~")
+				}
+				await scheduler.wait(5000)
+				if (isMainCharacter) {
+					checkedHomeserver = true
+					process.stdout.write("Connecting to homeserver... ")
+					await homeserverStatus.homeserverStatus.waitForOnline(true)
+					console.log("ok.\nReplaying past events. Welcome to Out Of Your Element.")
+				} else {
+					await homeserverStatus.homeserverStatus.waitForOnline(false)
+				}
+
 				await eventDispatcher.checkMissedExpressions(message.d)
 				await eventDispatcher.checkMissedMessages(client, message.d)
 				await eventDispatcher.checkMissedPins(client, message.d)

src/matrix/homeserver-status.js

@@ -11,7 +11,7 @@ const discordPackets = sync.require("../d2m/discord-packets")
 /** @type {import("../matrix/api")} */
 const api = sync.require("../matrix/api")
 
-const DEBUG_HOMESERVER_STATUS = true
+const DEBUG_HOMESERVER_STATUS = false
 
 function debugHomeserverStatus(message) {
 	if (DEBUG_HOMESERVER_STATUS) {
@@ -31,6 +31,19 @@ const homeserverStatus = new class HomeserverStatus {
 		this.sm = new StateMachine("online")
 			.defineState("online")
 
+			.defineState("checking", {
+				onEnter: [async () => {
+					const pingResult = await api.ping().catch(e => ({ok: false}))
+					if (pingResult.ok) {
+						this.sm.doTransition("check ok")
+					} else {
+						this.sm.doTransition("check fail")
+					}
+				}],
+				onLeave: [],
+				transitions: new Map()
+			})
+
 			.defineState("offline", {
 				onEnter: [() => {
 					this.pingInterval = setInterval(async () => {
@@ -64,9 +77,12 @@ const homeserverStatus = new class HomeserverStatus {
 			.defineUniversalTransition("error", "offline")
 			.defineTransition("offline", "ping ok", "recovering")
 			.defineTransition("recovering", "recovered", "online")
+			.defineTransition("online", "check", "checking")
+			.defineTransition("checking", "check ok", "recovering")
+			.defineTransition("checking", "check fail", "offline")
 
 		this.sm.on("enter", st => debugHomeserverStatus(`homeserver status: ${st}`))
-
+		this.sm.setMaxListeners(101)
 		this.sm.freeze()
 	}
 
@@ -74,6 +90,30 @@ const homeserverStatus = new class HomeserverStatus {
 		return this.sm.currentStateName === "online"
 	}
 
+	/** @param {boolean} forceCheck */
+	waitForOnline(forceCheck) {
+		const onlinePromise = new Promise(resolve => {
+			// Already online? Start check or just done
+			if (this.sm.currentStateName === "online") {
+				if (forceCheck) {
+					this.sm.doTransition("check")
+				} else {
+					return resolve(null)
+				}
+			}
+
+			// Checking or not online. Wait for online.
+			const onlineListener = stateName => {
+				if (stateName === "online") {
+					this.sm.removeListener("enter", onlineListener)
+					resolve(null)
+				}
+			}
+			this.sm.on("enter", onlineListener)
+		})
+		return onlinePromise
+	}
+
 	/**
 	 * When offline or recovering, call this for incoming packets to queue them to be sent in order later.
 	 */

start.js

@@ -31,8 +31,9 @@ sync.require("./src/m2d/event-dispatcher")
 
 ;(async () => {
 	await migrate.migrate(db)
+	process.stdout.write("Connecting to Discord... ")
 	await discord.cloud.connect()
-	console.log("Discord gateway started")
+	console.log("ok.")
 	sync.require("./src/web/server")
 	await power.applyPower()