moleculer
Version:
Fast & powerful microservices framework for Node.JS
416 lines (369 loc) • 10.7 kB
JavaScript
/*
* moleculer
* Copyright (c) 2023 MoleculerJS (https://github.com/moleculerjs/moleculer)
* MIT Licensed
*/
"use strict";
const _ = require("lodash");
const kleur = require("kleur");
const BaseDiscoverer = require("./base");
const { METRIC } = require("../../metrics");
const Serializers = require("../../serializers");
const { removeFromArray, randomInt } = require("../../utils");
const P = require("../../packets");
const C = require("../../constants");
let ETCD3;
/**
* Import types
*
* @typedef {import("./etcd3")} Etcd3DiscovererClass
* @typedef {import("./etcd3").Etcd3DiscovererOptions} Etcd3DiscovererOptions
* @typedef {import("../node")} Node
*/
/**
* etcd3-based Discoverer class
*
* @class Etcd3Discoverer
* @implements {Etcd3DiscovererClass}
*/
class Etcd3Discoverer extends BaseDiscoverer {
/**
* Creates an instance of Discoverer.
*
* TODO:
* - the etcd3 lib has no reconnection logic
*
* @param {Etcd3DiscovererOptions|string} opts
* @memberof Etcd3Discoverer
*/
constructor(opts) {
if (typeof opts === "string") opts = { etcd: { hosts: opts.replace(/etcd3:\/\//g, "") } };
super(opts);
this.opts = _.defaultsDeep(this.opts, {
etcd: undefined,
serializer: "JSON",
fullCheck: 10 // Disable with `0` or `null`
});
// Loop counter for full checks. Starts from a random value for better distribution
this.idx = this.opts.fullCheck > 1 ? randomInt(this.opts.fullCheck - 1) : 0;
// Etcd client instance
this.client = null;
// Last sequence numbers
this.lastInfoSeq = 0;
this.lastBeatSeq = 0;
// Leases
this.leaseBeat = null;
this.leaseInfo = null;
}
/**
* Initialize Discoverer
*
* @param {any} registry
*
* @memberof Etcd3Discoverer
*/
init(registry) {
super.init(registry);
try {
ETCD3 = require("etcd3");
} catch (err) {
/* istanbul ignore next */
this.broker.fatal(
"The 'etcd3' package is missing. Please install it with 'npm install etcd3 --save' command.",
err,
true
);
}
this.logger.warn(
kleur
.yellow()
.bold("Etcd3 Discoverer is an EXPERIMENTAL module. Do NOT use it in production!")
);
this.instanceHash = this.broker.instanceID.substring(0, 8);
this.PREFIX = `moleculer${
this.broker.namespace ? "-" + this.broker.namespace : ""
}/discovery`;
this.BEAT_KEY = `${this.PREFIX}/beats/${this.broker.nodeID}/${this.instanceHash}`;
this.INFO_KEY = `${this.PREFIX}/info/${this.broker.nodeID}`;
this.client = new ETCD3.Etcd3(this.opts.etcd);
// create an instance of serializer (default to JSON)
this.serializer = Serializers.resolve(this.opts.serializer);
this.serializer.init(this.broker);
this.logger.debug("Etcd3 Discoverer created. Prefix:", this.PREFIX);
}
/**
* Stop discoverer clients.
*/
stop() {
return super.stop().then(() => {
if (this.client) return this.client.close();
});
}
/**
* Register Moleculer Transit Core metrics.
*/
registerMoleculerMetrics() {
this.broker.metrics.register({
name: METRIC.MOLECULER_DISCOVERER_ETCD_COLLECT_TOTAL,
type: METRIC.TYPE_COUNTER,
rate: true,
description: "Number of Service Registry fetching from etcd"
});
this.broker.metrics.register({
name: METRIC.MOLECULER_DISCOVERER_ETCD_COLLECT_TIME,
type: METRIC.TYPE_HISTOGRAM,
quantiles: true,
unit: METRIC.UNIT_MILLISECONDS,
description: "Time of Service Registry fetching from etcd"
});
}
/**
* Sending a local heartbeat to etcd.
*/
sendHeartbeat() {
const timeEnd = this.broker.metrics.timer(METRIC.MOLECULER_DISCOVERER_ETCD_COLLECT_TIME);
const data = {
sender: this.broker.nodeID,
ver: this.broker.PROTOCOL_VERSION,
//timestamp: Date.now(),
cpu: this.localNode.cpu,
seq: this.localNode.seq,
instanceID: this.broker.instanceID
};
const seq = this.localNode.seq;
const key = this.BEAT_KEY + "/" + seq;
let leaseBeat = this.leaseBeat;
return this.Promise.resolve()
.then(() => {
if (leaseBeat) {
if (seq != this.lastBeatSeq) {
// If seq changed, revoke the current lease
const p = leaseBeat.revoke();
leaseBeat = null;
return p;
}
}
})
.then(() => {
if (!leaseBeat) {
// Create a new for lease
leaseBeat = this.client.lease(this.opts.heartbeatTimeout);
//Handle lease-lost event. Release lease when lost. Next heartbeat will request a new lease
leaseBeat.on("lost", err => {
this.logger.warn(
"Lost heartbeat lease. Dropping lease and retrying heartbeat. Error:",
err.message
);
leaseBeat.release();
this.leaseBeat = null;
// if broker is connected, send heartbeat immediately. Otherwise it is sent on reconnect.
if (this.broker.transit.connected) {
this.sendHeartbeat();
}
});
return leaseBeat
.grant() // Waiting for the lease creation on the server
.then(() => (this.leaseBeat = leaseBeat));
}
})
.then(() =>
this.leaseBeat.put(key).value(this.serializer.serialize(data, P.PACKET_HEARTBEAT))
)
.then(() => (this.lastBeatSeq = seq))
.then(() => this.collectOnlineNodes())
.catch(err => {
this.logger.error("Error occurred while collect etcd keys.", err);
this.broker.broadcastLocal("$discoverer.error", {
error: err,
module: "discoverer",
type: C.FAILED_COLLECT_KEYS
});
})
.then(() => {
timeEnd();
this.broker.metrics.increment(METRIC.MOLECULER_DISCOVERER_ETCD_COLLECT_TOTAL);
});
}
/**
* Collect online nodes from etcd server.
*/
collectOnlineNodes() {
// Get the current node list so that we can check the disconnected nodes.
const prevNodes = this.registry.nodes
.list({ onlyAvailable: true, withServices: false })
.map(node => node.id)
.filter(nodeID => nodeID !== this.broker.nodeID);
// Collect the online node keys.
return this.Promise.resolve()
.then(() => {
if (this.opts.fullCheck && ++this.idx % this.opts.fullCheck === 0) {
// Full check
//this.logger.debug("Full check", this.idx);
this.idx = 0;
return this.client
.getAll()
.prefix(`${this.PREFIX}/beats/`)
.buffers()
.then(result =>
Object.values(result).map(raw => {
try {
return this.serializer.deserialize(raw, P.PACKET_INFO);
} catch (err) {
this.logger.warn("Unable to parse HEARTBEAT packet", err, raw);
}
})
);
} else {
//this.logger.debug("Lazy check", this.idx);
// Lazy check
return this.client
.getAll()
.prefix(`${this.PREFIX}/beats/`)
.keys()
.then(keys =>
keys.map(key => {
const p = key.substring(`${this.PREFIX}/beats/`.length).split("/");
return {
key,
sender: p[0],
instanceID: p[1],
seq: Number(p[2])
};
})
);
}
})
.then(packets => {
_.compact(packets).map(packet => {
if (packet.sender == this.broker.nodeID) return;
removeFromArray(prevNodes, packet.sender);
this.heartbeatReceived(packet.sender, packet);
});
})
.then(() => {
if (prevNodes.length > 0) {
// Disconnected nodes
prevNodes.map(nodeID => {
this.logger.info(
`The node '${nodeID}' is not available. Removing from registry...`
);
this.remoteNodeDisconnected(nodeID, true);
});
}
});
}
/**
* Discover a new or old node.
*
* @param {String} nodeID
* @returns {Promise<Node | void>}
*/
discoverNode(nodeID) {
return this.client
.get(`${this.PREFIX}/info/${nodeID}`)
.buffer()
.then(res => {
if (!res) {
this.logger.warn(`No INFO for '${nodeID}' node in registry.`);
return;
}
try {
const info = this.serializer.deserialize(res, P.PACKET_INFO);
return this.processRemoteNodeInfo(nodeID, info);
} catch (err) {
this.logger.warn("Unable to parse INFO packet", err, res);
}
});
}
/**
* Discover all nodes (after connected)
* @returns {Promise<Node[] | void>}
*/
discoverAllNodes() {
return this.collectOnlineNodes();
}
/**
* Local service registry has been changed. We should notify remote nodes.
* @param {String=} nodeID
* @returns {Promise<void>}
*/
sendLocalNodeInfo(nodeID) {
const info = this.broker.getLocalNodeInfo();
const payload = Object.assign(
{
ver: this.broker.PROTOCOL_VERSION,
sender: this.broker.nodeID
},
info
);
const key = this.INFO_KEY;
const seq = this.localNode.seq;
let leaseInfo = this.leaseInfo;
const p =
!nodeID && this.broker.options.disableBalancer
? this.transit.tx.makeBalancedSubscriptions()
: this.Promise.resolve();
return p
.then(() => {
if (leaseInfo) {
if (seq != this.lastInfoSeq) {
const p = leaseInfo.revoke();
leaseInfo = null;
return p;
}
}
})
.then(() => {
if (!leaseInfo) {
leaseInfo = this.client.lease(60);
//Handle lease-lost event. Release lease when lost. Next heartbeat will request a new lease
leaseInfo.on("lost", err => {
this.logger.warn(
"Lost info lease. Dropping lease and retrying info-send. Error:",
err.message
);
leaseInfo.release();
this.leaseInfo = null;
// if broker is connected, send local node info immediately. Otherwise it is sent on reconnect.
if (this.broker.transit.connected) {
this.sendLocalNodeInfo(nodeID);
}
});
return leaseInfo
.grant() // Waiting for the lease creation on the server
.then(() => (this.leaseInfo = leaseInfo));
}
})
.then(() => leaseInfo.put(key).value(this.serializer.serialize(payload, P.PACKET_INFO)))
.then(() => {
this.lastInfoSeq = seq;
// Sending a new heartbeat because it contains the `seq`
if (!nodeID) return this.beat();
})
.catch(err => {
this.logger.error("Unable to send INFO to etcd server", err);
this.broker.broadcastLocal("$discoverer.error", {
error: err,
module: "discoverer",
type: C.FAILED_SEND_INFO
});
});
}
/**
* Unregister local node after disconnecting.
*/
localNodeDisconnected() {
return this.Promise.resolve()
.then(() => super.localNodeDisconnected())
.then(() => this.logger.debug("Remove local node from registry..."))
.then(() => this.client.delete().key(this.INFO_KEY))
.then(() => this.client.delete().key(this.BEAT_KEY))
.then(() => {
if (this.leaseBeat) return this.leaseBeat.revoke();
})
.then(() => {
if (this.leaseInfo) return this.leaseInfo.revoke();
});
}
}
module.exports = Etcd3Discoverer;