n8n/dist/scaling/multi-main-setup.ee.js

n8n Workflow Automation Tool

"use strict";
var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
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    return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __metadata = (this && this.__metadata) || function (k, v) {
    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
};
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.MultiMainSetup = void 0;
const config_1 = require("@n8n/config");
const di_1 = require("@n8n/di");
const n8n_core_1 = require("n8n-core");
const config_2 = __importDefault(require("../config"));
const constants_1 = require("../constants");
const publisher_service_1 = require("../scaling/pubsub/publisher.service");
const redis_client_service_1 = require("../services/redis-client.service");
const typed_emitter_1 = require("../typed-emitter");
let MultiMainSetup = class MultiMainSetup extends typed_emitter_1.TypedEmitter {
    constructor(logger, instanceSettings, publisher, redisClientService, globalConfig) {
        super();
        this.logger = logger;
        this.instanceSettings = instanceSettings;
        this.publisher = publisher;
        this.redisClientService = redisClientService;
        this.globalConfig = globalConfig;
        this.leaderKeyTtl = this.globalConfig.multiMainSetup.ttl;
        this.logger = this.logger.scoped(['scaling', 'multi-main-setup']);
    }
    async init() {
        const prefix = config_2.default.getEnv('redis.prefix');
        const validPrefix = this.redisClientService.toValidPrefix(prefix);
        this.leaderKey = validPrefix + ':main_instance_leader';
        await this.tryBecomeLeader();
        this.leaderCheckInterval = setInterval(async () => {
            await this.checkLeader();
        }, this.globalConfig.multiMainSetup.interval * constants_1.Time.seconds.toMilliseconds);
    }
    async shutdown() {
        clearInterval(this.leaderCheckInterval);
        const { isLeader } = this.instanceSettings;
        if (isLeader)
            await this.publisher.clear(this.leaderKey);
    }
    async checkLeader() {
        const leaderId = await this.publisher.get(this.leaderKey);
        const { hostId } = this.instanceSettings;
        if (leaderId === hostId) {
            this.logger.debug(`[Instance ID ${hostId}] Leader is this instance`);
            await this.publisher.setExpiration(this.leaderKey, this.leaderKeyTtl);
            return;
        }
        if (leaderId && leaderId !== hostId) {
            this.logger.debug(`[Instance ID ${hostId}] Leader is other instance "${leaderId}"`);
            if (this.instanceSettings.isLeader) {
                this.instanceSettings.markAsFollower();
                this.emit('leader-stepdown');
                this.logger.warn('[Multi-main setup] Leader failed to renew leader key');
            }
            return;
        }
        if (!leaderId) {
            this.logger.debug(`[Instance ID ${hostId}] Leadership vacant, attempting to become leader...`);
            this.instanceSettings.markAsFollower();
            this.emit('leader-stepdown');
            await this.tryBecomeLeader();
        }
    }
    async tryBecomeLeader() {
        const { hostId } = this.instanceSettings;
        const keySetSuccessfully = await this.publisher.setIfNotExists(this.leaderKey, hostId);
        if (keySetSuccessfully) {
            this.logger.debug(`[Instance ID ${hostId}] Leader is now this instance`);
            this.instanceSettings.markAsLeader();
            await this.publisher.setExpiration(this.leaderKey, this.leaderKeyTtl);
            this.emit('leader-takeover');
        }
        else {
            this.instanceSettings.markAsFollower();
        }
    }
    async fetchLeaderKey() {
        return await this.publisher.get(this.leaderKey);
    }
};
exports.MultiMainSetup = MultiMainSetup;
exports.MultiMainSetup = MultiMainSetup = __decorate([
    (0, di_1.Service)(),
    __metadata("design:paramtypes", [n8n_core_1.Logger,
        n8n_core_1.InstanceSettings,
        publisher_service_1.Publisher,
        redis_client_service_1.RedisClientService,
        config_1.GlobalConfig])
], MultiMainSetup);
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