n8n/dist/scaling/multi-main-setup-v2.js

n8n Workflow Automation Tool

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.MultiMainSetupV2 = void 0;
const node_assert_1 = __importDefault(require("node:assert"));
class MultiMainSetupV2 {
    get hostId() {
        return this.instanceSettings.hostId;
    }
    constructor(logger, instanceSettings, errorReporter, client, emit) {
        this.logger = logger;
        this.instanceSettings = instanceSettings;
        this.errorReporter = errorReporter;
        this.client = client;
        this.emit = emit;
        this.leaderCheckInProgress = false;
    }
    async init() {
        const result = await this.client.setLeaderIfNotExists();
        if (!result.ok) {
            this.logRedisCommandFailure('Failed to set leader key in Redis during init', result.error);
            this.instanceSettings.markAsFollower();
        }
        else if (result.result) {
            this.takeOverAsLeader();
        }
        else {
            this.instanceSettings.markAsFollower();
        }
    }
    async shutdown() {
        const { isLeader } = this.instanceSettings;
        if (isLeader) {
            const result = await this.client.clearLeader();
            if (!result.ok) {
                this.logger.warn('Failed to clear leader key from Redis', { error: result.error });
            }
        }
        this.client.destroy();
    }
    async checkLeader() {
        if (this.leaderCheckInProgress) {
            this.logger.warn('Previous leader check is still in progress, skipping this check');
            return;
        }
        this.leaderCheckInProgress = true;
        try {
            if (this.instanceSettings.isLeader) {
                await this.checkAreWeStillLeader();
            }
            else {
                await this.checkCanBecomeLeader();
            }
        }
        finally {
            this.leaderCheckInProgress = false;
        }
    }
    async checkAreWeStillLeader() {
        (0, node_assert_1.default)(this.instanceSettings.isLeader);
        const renewTtlResult = await this.client.tryRenewLeaderTtl();
        if (!renewTtlResult.ok) {
            this.logRedisCommandFailure('Failed to renew leader TTL', renewTtlResult.error);
            return;
        }
        const renewalResult = renewTtlResult.result;
        if (renewalResult.id === 'success') {
            this.logger.debug(`[Instance ID ${this.hostId}] Leader is this instance`);
            return;
        }
        this.logger.warn('[Multi-main setup] Leader failed to renew leader key');
        if (renewalResult.id === 'other-host-is-leader') {
            this.logger.debug(`[Instance ID ${this.hostId}] Leader is other instance "${renewalResult.currentLeaderId}"`);
            this.stepDownToFollower();
            return;
        }
        (0, node_assert_1.default)(renewalResult.id === 'key-missing');
        const result = await this.client.setLeaderIfNotExists();
        if (!result.ok) {
            this.logRedisCommandFailure('Failed to set leader key in Redis', result.error);
            this.stepDownToFollower();
            return;
        }
        const wasSet = result.result;
        if (!wasSet) {
            this.stepDownToFollower();
        }
    }
    async checkCanBecomeLeader() {
        (0, node_assert_1.default)(!this.instanceSettings.isLeader);
        const getResult = await this.client.getLeader();
        if (!getResult.ok) {
            this.logRedisCommandFailure('Failed to get leader key from Redis', getResult.error);
            return;
        }
        const leaderId = getResult.result;
        if (leaderId && leaderId === this.hostId) {
            this.errorReporter.info(`[Instance ID ${this.hostId}] Remote/Local leadership mismatch, marking self as leader`, {
                shouldBeLogged: true,
                shouldReport: true,
            });
            this.takeOverAsLeader();
            return;
        }
        if (leaderId) {
            this.logger.debug(`[Instance ID ${this.hostId}] Leader is other instance "${leaderId}"`);
            return;
        }
        this.logger.debug(`[Instance ID ${this.hostId}] Leadership vacant, attempting to become leader...`);
        const result = await this.client.setLeaderIfNotExists();
        if (!result.ok) {
            this.logger.warn('Failed to try leader key set in Redis', { error: result.error });
            return;
        }
        const wasSet = result.result;
        if (wasSet) {
            this.takeOverAsLeader();
        }
    }
    takeOverAsLeader() {
        (0, node_assert_1.default)(!this.instanceSettings.isLeader);
        this.logger.info(`[Instance ID ${this.hostId}] Leader is now this instance`);
        this.instanceSettings.markAsLeader();
        this.emit('leader-takeover');
    }
    stepDownToFollower() {
        (0, node_assert_1.default)(this.instanceSettings.isLeader);
        this.logger.info(`[Instance ID ${this.hostId}] This is now a follower instance`);
        this.instanceSettings.markAsFollower();
        this.emit('leader-stepdown');
    }
    async fetchLeaderKey() {
        const result = await this.client.getLeader();
        return result.ok ? result.result : null;
    }
    logRedisCommandFailure(message, error) {
        this.logger.warn(`${message}: ${error.message}`, { error });
    }
}
exports.MultiMainSetupV2 = MultiMainSetupV2;
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