diff --git a/src/sharding/Shard.js b/src/sharding/Shard.js
index 9bb157623..b6fddb420 100644
--- a/src/sharding/Shard.js
+++ b/src/sharding/Shard.js
@@ -1,17 +1,19 @@
const childProcess = require('child_process');
+const EventEmitter = require('events');
const path = require('path');
const Util = require('../util/Util');
/**
* Represents a Shard spawned by the ShardingManager.
*/
-class Shard {
+class Shard extends EventEmitter {
/**
* @param {ShardingManager} manager The sharding manager
* @param {number} id The ID of this shard
* @param {Array} [args=[]] Command line arguments to pass to the script
*/
constructor(manager, id, args = []) {
+ super();
/**
* Manager that created the shard
* @type {ShardingManager}
@@ -35,19 +37,77 @@ class Shard {
});
/**
- * Process of the shard
- * @type {ChildProcess}
+ * Whether the shard's {@link Client} is ready
+ * @type {boolean}
*/
- this.process = childProcess.fork(path.resolve(this.manager.file), args, {
- env: this.env,
- });
- this.process.on('message', this._handleMessage.bind(this));
- this.process.once('exit', () => {
- if (this.manager.respawn) this.manager.createShard(this.id);
- });
+ this.ready = false;
this._evals = new Map();
this._fetches = new Map();
+
+ /**
+ * Listener function for the {@link ChildProcess}' `exit` event
+ * @type {Function}
+ * @private
+ */
+ this._exitListener = this._handleExit.bind(this, undefined);
+
+ /**
+ * Process of the shard
+ * @type {ChildProcess}
+ */
+ this.process = null;
+
+ this.spawn(args);
+ }
+
+ /**
+ * Forks a child process for the shard.
+ * You should not need to call this manually.
+ * @param {Array} [args=this.manager.args] Command line arguments to pass to the script
+ * @param {Array} [execArgv=this.manager.execArgv] Command line arguments to pass to the process executable
+ * @returns {ChildProcess}
+ */
+ spawn(args = this.manager.args, execArgv = this.manager.execArgv) {
+ this.process = childProcess.fork(path.resolve(this.manager.file), args, {
+ env: this.env, execArgv,
+ })
+ .on('exit', this._exitListener)
+ .on('message', this._handleMessage.bind(this));
+
+ /**
+ * Emitted upon the creation of the shard's child process.
+ * @event Shard#spawn
+ * @param {ChildProcess} process Child process that was created
+ */
+ this.emit('spawn', this.process);
+
+ return new Promise((resolve, reject) => {
+ this.once('ready', resolve);
+ this.once('disconnect', () => reject(new Error(`Shard ${this.id}'s Client disconnected before becoming ready.`)));
+ this.once('death', () => reject(new Error(`Shard ${this.id}'s process exited before its Client became ready.`)));
+ setTimeout(() => reject(new Error(`Shard ${this.id}'s Client took too long to become ready.`)), 30000);
+ }).then(() => this.process);
+ }
+
+ /**
+ * Immediately kills the shard's process and does not restart it.
+ */
+ kill() {
+ this.process.removeListener('exit', this._exitListener);
+ this.process.kill();
+ this._handleExit(false);
+ }
+
+ /**
+ * Kills and restarts the shard's process.
+ * @param {number} [delay=500] How long to wait between killing the process and restarting it (in milliseconds)
+ * @returns {Promise}
+ */
+ respawn(delay = 500) {
+ this.kill();
+ if (delay > 0) return Util.delayFor(delay).then(() => this.spawn());
+ return this.spawn();
}
/**
@@ -130,6 +190,39 @@ class Shard {
*/
_handleMessage(message) {
if (message) {
+ // Shard is ready
+ if (message._ready) {
+ this.ready = true;
+ /**
+ * Emitted upon the shard's {@link Client#ready} event.
+ * @event Shard#ready
+ */
+ this.emit('ready');
+ return;
+ }
+
+ // Shard has disconnected
+ if (message._disconnect) {
+ this.ready = false;
+ /**
+ * Emitted upon the shard's {@link Client#disconnect} event.
+ * @event Shard#disconnect
+ */
+ this.emit('disconnect');
+ return;
+ }
+
+ // Shard is attempting to reconnect
+ if (message._reconnecting) {
+ this.ready = false;
+ /**
+ * Emitted upon the shard's {@link Client#reconnecting} event.
+ * @event Shard#reconnecting
+ */
+ this.emit('reconnecting');
+ return;
+ }
+
// Shard is requesting a property fetch
if (message._sFetchProp) {
this.manager.fetchClientValues(message._sFetchProp).then(
@@ -156,6 +249,33 @@ class Shard {
* @param {*} message Message that was received
*/
this.manager.emit('message', this, message);
+
+ /**
+ * Emitted upon recieving a message from the child process.
+ * @event Shard#message
+ * @param {*} message Message that was received
+ */
+ this.emit('message', message);
+ }
+
+ /**
+ * Handles the shard's process exiting.
+ * @param {boolean} [respawn=this.manager.respawn] Whether to spawn the shard again
+ * @private
+ */
+ _handleExit(respawn = this.manager.respawn) {
+ /**
+ * Emitted upon the shard's child process exiting.
+ * @event Shard#death
+ * @param {ChildProcess} process Child process that exited
+ */
+ this.emit('death', this.process);
+
+ this.process = null;
+ this._evals.clear();
+ this._fetches.clear();
+
+ if (respawn) this.manager.createShard(this.id);
}
}
diff --git a/src/sharding/ShardClientUtil.js b/src/sharding/ShardClientUtil.js
index 8541c3578..28571f1f9 100644
--- a/src/sharding/ShardClientUtil.js
+++ b/src/sharding/ShardClientUtil.js
@@ -10,6 +10,9 @@ class ShardClientUtil {
constructor(client) {
this.client = client;
process.on('message', this._handleMessage.bind(this));
+ client.on('ready', () => { process.send({ _ready: true }); });
+ client.on('disconnect', () => { process.send({ _disconnect: true }); });
+ client.on('reconnecting', () => { process.send({ _reconnecting: true }); });
}
/**
diff --git a/src/sharding/ShardingManager.js b/src/sharding/ShardingManager.js
index aa40547bd..d5e31edad 100644
--- a/src/sharding/ShardingManager.js
+++ b/src/sharding/ShardingManager.js
@@ -66,6 +66,12 @@ class ShardingManager extends EventEmitter {
*/
this.shardArgs = options.shardArgs;
+ /**
+ * Arguments for the shard's process executable
+ * @type {?string[]}
+ */
+ this.execArgv = options.execArgv;
+
/**
* Token to use for obtaining the automatic shard count, and passing to shards
* @type {?string}
@@ -189,6 +195,26 @@ class ShardingManager extends EventEmitter {
for (const shard of this.shards.values()) promises.push(shard.fetchClientValue(prop));
return Promise.all(promises);
}
+
+ /**
+ * Kills all running shards and respawns them.
+ * @param {number} [shardDelay=5000] How long to wait between shards (in milliseconds)
+ * @param {number} [respawnDelay=500] How long to wait between killing a shard's process and restarting it
+ * (in milliseconds)
+ * @param {boolean} [waitForReady=true] Whether to wait for a shard to become ready before continuing to another
+ * @param {number} [currentShardIndex=0] The shard index to start respawning at
+ * @returns {Promise>}
+ */
+ respawnAll(shardDelay = 5000, respawnDelay = 500, waitForReady = true, currentShardIndex = 0) {
+ let s = 0;
+ const shard = this.shards.get(currentShardIndex);
+ const promises = [shard.respawn(respawnDelay, waitForReady)];
+ if (++s < this.shards.size && shardDelay > 0) promises.push(Util.delayFor(shardDelay));
+ return Promise.all(promises).then(() => {
+ if (++currentShardIndex === this.shards.size) return this.shards;
+ return this.respawnAll(shardDelay, respawnDelay, waitForReady, currentShardIndex);
+ });
+ }
}
module.exports = ShardingManager;
diff --git a/src/util/Util.js b/src/util/Util.js
index 2be7c5658..7fa6d33fa 100644
--- a/src/util/Util.js
+++ b/src/util/Util.js
@@ -202,6 +202,18 @@ class Util {
}
return array.indexOf(element);
}
+
+ /**
+ * Creates a Promise that resolves after a specified duration.
+ * @param {number} ms How long to wait before resolving (in milliseconds)
+ * @returns {Promise}
+ * @private
+ */
+ static delayFor(ms) {
+ return new Promise(resolve => {
+ setTimeout(resolve, ms);
+ });
+ }
}
module.exports = Util;