refactor: rename constant to a more sensible name

[e-mobility-charging-stations-simulator.git] / src / charging-station / Bootstrap.ts

// Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved.

import { EventEmitter } from 'node:events';
import { dirname, extname, join } from 'node:path';
import process, { exit } from 'node:process';
import { fileURLToPath } from 'node:url';

import chalk from 'chalk';
import { availableParallelism } from 'poolifier';

import { waitChargingStationEvents } from './Helpers';
import type { AbstractUIServer } from './ui-server/AbstractUIServer';
import { UIServerFactory } from './ui-server/UIServerFactory';
import { version } from '../../package.json';
import { BaseError } from '../exception';
import { type Storage, StorageFactory } from '../performance';
import {
  type ChargingStationData,
  type ChargingStationWorkerData,
  type ChargingStationWorkerMessage,
  type ChargingStationWorkerMessageData,
  ChargingStationWorkerMessageEvents,
  ConfigurationSection,
  ProcedureName,
  type StationTemplateUrl,
  type Statistics,
  type StorageConfiguration,
  type UIServerConfiguration,
  type WorkerConfiguration,
} from '../types';
import {
  Configuration,
  Constants,
  formatDurationMilliSeconds,
  generateUUID,
  handleUncaughtException,
  handleUnhandledRejection,
  isNotEmptyArray,
  isNullOrUndefined,
  logPrefix,
  logger,
} from '../utils';
import { type WorkerAbstract, WorkerFactory } from '../worker';

const moduleName = 'Bootstrap';

enum exitCodes {
  succeeded = 0,
  missingChargingStationsConfiguration = 1,
  noChargingStationTemplates = 2,
  gracefulShutdownError = 3,
}

export class Bootstrap extends EventEmitter {
  private static instance: Bootstrap | null = null;
  public numberOfChargingStations!: number;
  public numberOfChargingStationTemplates!: number;
  private workerImplementation: WorkerAbstract<ChargingStationWorkerData> | null;
  private readonly uiServer: AbstractUIServer | null;
  private readonly storage!: Storage;
  private numberOfStartedChargingStations!: number;
  private readonly version: string = version;
  private initializedCounters: boolean;
  private started: boolean;
  private starting: boolean;
  private stopping: boolean;
  private readonly workerScript: string;

  private constructor() {
    super();
    for (const signal of ['SIGINT', 'SIGQUIT', 'SIGTERM']) {
      process.on(signal, this.gracefulShutdown.bind(this));
    }
    // Enable unconditionally for now
    handleUnhandledRejection();
    handleUncaughtException();
    this.started = false;
    this.starting = false;
    this.stopping = false;
    this.initializedCounters = false;
    this.initializeCounters();
    this.workerImplementation = null;
    this.workerScript = join(
      dirname(fileURLToPath(import.meta.url)),
      `ChargingStationWorker${extname(fileURLToPath(import.meta.url))}`,
    );
    this.uiServer = UIServerFactory.getUIServerImplementation(
      Configuration.getConfigurationSection<UIServerConfiguration>(ConfigurationSection.uiServer),
    );
    const performanceStorageConfiguration =
      Configuration.getConfigurationSection<StorageConfiguration>(
        ConfigurationSection.performanceStorage,
      );
    performanceStorageConfiguration.enabled === true &&
      (this.storage = StorageFactory.getStorage(
        performanceStorageConfiguration.type!,
        performanceStorageConfiguration.uri!,
        this.logPrefix(),
      ));
    Configuration.configurationChangeCallback = async () => Bootstrap.getInstance().restart(false);
  }

  public static getInstance(): Bootstrap {
    if (Bootstrap.instance === null) {
      Bootstrap.instance = new Bootstrap();
    }
    return Bootstrap.instance;
  }

  public async start(): Promise<void> {
    if (this.started === false) {
      if (this.starting === false) {
        this.starting = true;
        this.initializeCounters();
        const workerConfiguration = Configuration.getConfigurationSection<WorkerConfiguration>(
          ConfigurationSection.worker,
        );
        this.initializeWorkerImplementation(workerConfiguration);
        await this.workerImplementation?.start();
        await this.storage?.open();
        Configuration.getConfigurationSection<UIServerConfiguration>(ConfigurationSection.uiServer)
          .enabled === true && this.uiServer?.start();
        // Start ChargingStation object instance in worker thread
        for (const stationTemplateUrl of Configuration.getStationTemplateUrls()!) {
          try {
            const nbStations = stationTemplateUrl.numberOfStations ?? 0;
            for (let index = 1; index <= nbStations; index++) {
              await this.startChargingStation(index, stationTemplateUrl);
            }
          } catch (error) {
            console.error(
              chalk.red(
                `Error at starting charging station with template file ${stationTemplateUrl.file}: `,
              ),
              error,
            );
          }
        }
        console.info(
          chalk.green(
            `Charging stations simulator ${
              this.version
            } started with ${this.numberOfChargingStations.toString()} charging station(s) from ${this.numberOfChargingStationTemplates.toString()} configured charging station template(s) and ${
              Configuration.workerDynamicPoolInUse()
                ? `${workerConfiguration.poolMinSize?.toString()}/`
                : ''
            }${this.workerImplementation?.size}${
              Configuration.workerPoolInUse()
                ? `/${workerConfiguration.poolMaxSize?.toString()}`
                : ''
            } worker(s) concurrently running in '${workerConfiguration.processType}' mode${
              !isNullOrUndefined(this.workerImplementation?.maxElementsPerWorker)
                ? ` (${this.workerImplementation?.maxElementsPerWorker} charging station(s) per worker)`
                : ''
            }`,
          ),
        );
        Configuration.workerDynamicPoolInUse() &&
          console.warn(
            chalk.yellow(
              'Charging stations simulator is using dynamic pool mode. This is an experimental feature with known issues.\nPlease consider using fixed pool or worker set mode instead',
            ),
          );
        console.info(chalk.green('Worker set/pool information:'), this.workerImplementation?.info);
        this.started = true;
        this.starting = false;
      } else {
        console.error(chalk.red('Cannot start an already starting charging stations simulator'));
      }
    } else {
      console.error(chalk.red('Cannot start an already started charging stations simulator'));
    }
  }

  public async stop(stopChargingStations = true): Promise<void> {
    if (this.started === true) {
      if (this.stopping === false) {
        this.stopping = true;
        if (stopChargingStations === true) {
          await this.uiServer?.sendInternalRequest(
            this.uiServer.buildProtocolRequest(
              generateUUID(),
              ProcedureName.STOP_CHARGING_STATION,
              Constants.EMPTY_FROZEN_OBJECT,
            ),
          );
          try {
            await this.waitChargingStationsStopped();
          } catch (error) {
            console.error(chalk.red('Error while waiting for charging stations to stop: '), error);
          }
        }
        await this.workerImplementation?.stop();
        this.workerImplementation = null;
        this.uiServer?.stop();
        await this.storage?.close();
        this.resetCounters();
        this.initializedCounters = false;
        this.started = false;
        this.stopping = false;
      } else {
        console.error(chalk.red('Cannot stop an already stopping charging stations simulator'));
      }
    } else {
      console.error(chalk.red('Cannot stop an already stopped charging stations simulator'));
    }
  }

  public async restart(stopChargingStations?: boolean): Promise<void> {
    await this.stop(stopChargingStations);
    await this.start();
  }

  private async waitChargingStationsStopped(): Promise<string> {
    return new Promise<string>((resolve, reject) => {
      const waitTimeout = setTimeout(() => {
        const message = `Timeout ${formatDurationMilliSeconds(
          Constants.STOP_CHARGING_STATIONS_TIMEOUT,
        )} reached at stopping charging stations`;
        console.warn(chalk.yellow(message));
        reject(new Error(message));
      }, Constants.STOP_CHARGING_STATIONS_TIMEOUT);
      waitChargingStationEvents(
        this,
        ChargingStationWorkerMessageEvents.stopped,
        this.numberOfChargingStations,
      )
        .then(() => {
          resolve('Charging stations stopped');
        })
        .catch((error) => {
          reject(error);
        })
        .finally(() => {
          clearTimeout(waitTimeout);
        });
    });
  }

  private initializeWorkerImplementation(workerConfiguration: WorkerConfiguration): void {
    let elementsPerWorker: number | undefined;
    if (workerConfiguration?.elementsPerWorker === 'auto') {
      elementsPerWorker =
        this.numberOfChargingStations > availableParallelism()
          ? Math.round(this.numberOfChargingStations / (availableParallelism() * 1.5))
          : 1;
    }
    this.workerImplementation === null &&
      (this.workerImplementation = WorkerFactory.getWorkerImplementation<ChargingStationWorkerData>(
        this.workerScript,
        workerConfiguration.processType!,
        {
          workerStartDelay: workerConfiguration.startDelay,
          elementStartDelay: workerConfiguration.elementStartDelay,
          poolMaxSize: workerConfiguration.poolMaxSize!,
          poolMinSize: workerConfiguration.poolMinSize!,
          elementsPerWorker: elementsPerWorker ?? (workerConfiguration.elementsPerWorker as number),
          poolOptions: {
            messageHandler: this.messageHandler.bind(this) as (message: unknown) => void,
          },
        },
      ));
  }

  private messageHandler(
    msg: ChargingStationWorkerMessage<ChargingStationWorkerMessageData>,
  ): void {
    // logger.debug(
    //   `${this.logPrefix()} ${moduleName}.messageHandler: Worker channel message received: ${JSON.stringify(
    //     msg,
    //     undefined,
    //     2,
    //   )}`,
    // );
    try {
      switch (msg.event) {
        case ChargingStationWorkerMessageEvents.started:
          this.workerEventStarted(msg.data as ChargingStationData);
          this.emit(ChargingStationWorkerMessageEvents.started, msg.data as ChargingStationData);
          break;
        case ChargingStationWorkerMessageEvents.stopped:
          this.workerEventStopped(msg.data as ChargingStationData);
          this.emit(ChargingStationWorkerMessageEvents.stopped, msg.data as ChargingStationData);
          break;
        case ChargingStationWorkerMessageEvents.updated:
          this.workerEventUpdated(msg.data as ChargingStationData);
          this.emit(ChargingStationWorkerMessageEvents.updated, msg.data as ChargingStationData);
          break;
        case ChargingStationWorkerMessageEvents.performanceStatistics:
          this.workerEventPerformanceStatistics(msg.data as Statistics);
          this.emit(
            ChargingStationWorkerMessageEvents.performanceStatistics,
            msg.data as Statistics,
          );
          break;
        case ChargingStationWorkerMessageEvents.startWorkerElementError:
          logger.error(
            `${this.logPrefix()} ${moduleName}.messageHandler: Error occured while starting worker element:`,
            msg.data,
          );
          this.emit(ChargingStationWorkerMessageEvents.startWorkerElementError, msg.data);
          break;
        case ChargingStationWorkerMessageEvents.startedWorkerElement:
          break;
        default:
          throw new BaseError(
            `Unknown charging station worker event: '${
              msg.event
            }' received with data: ${JSON.stringify(msg.data, undefined, 2)}`,
          );
      }
    } catch (error) {
      logger.error(
        `${this.logPrefix()} ${moduleName}.messageHandler: Error occurred while handling '${
          msg.event
        }' event:`,
        error,
      );
    }
  }

  private workerEventStarted = (data: ChargingStationData) => {
    this.uiServer?.chargingStations.set(data.stationInfo.hashId, data);
    ++this.numberOfStartedChargingStations;
    logger.info(
      `${this.logPrefix()} ${moduleName}.workerEventStarted: Charging station ${
        data.stationInfo.chargingStationId
      } (hashId: ${data.stationInfo.hashId}) started (${
        this.numberOfStartedChargingStations
      } started from ${this.numberOfChargingStations})`,
    );
  };

  private workerEventStopped = (data: ChargingStationData) => {
    this.uiServer?.chargingStations.set(data.stationInfo.hashId, data);
    --this.numberOfStartedChargingStations;
    logger.info(
      `${this.logPrefix()} ${moduleName}.workerEventStopped: Charging station ${
        data.stationInfo.chargingStationId
      } (hashId: ${data.stationInfo.hashId}) stopped (${
        this.numberOfStartedChargingStations
      } started from ${this.numberOfChargingStations})`,
    );
  };

  private workerEventUpdated = (data: ChargingStationData) => {
    this.uiServer?.chargingStations.set(data.stationInfo.hashId, data);
  };

  private workerEventPerformanceStatistics = (data: Statistics) => {
    this.storage.storePerformanceStatistics(data) as void;
  };

  private initializeCounters() {
    if (this.initializedCounters === false) {
      this.resetCounters();
      const stationTemplateUrls = Configuration.getStationTemplateUrls()!;
      if (isNotEmptyArray(stationTemplateUrls)) {
        this.numberOfChargingStationTemplates = stationTemplateUrls.length;
        for (const stationTemplateUrl of stationTemplateUrls) {
          this.numberOfChargingStations += stationTemplateUrl.numberOfStations ?? 0;
        }
      } else {
        console.warn(
          chalk.yellow("'stationTemplateUrls' not defined or empty in configuration, exiting"),
        );
        exit(exitCodes.missingChargingStationsConfiguration);
      }
      if (this.numberOfChargingStations === 0) {
        console.warn(
          chalk.yellow('No charging station template enabled in configuration, exiting'),
        );
        exit(exitCodes.noChargingStationTemplates);
      }
      this.initializedCounters = true;
    }
  }

  private resetCounters(): void {
    this.numberOfChargingStationTemplates = 0;
    this.numberOfChargingStations = 0;
    this.numberOfStartedChargingStations = 0;
  }

  private async startChargingStation(
    index: number,
    stationTemplateUrl: StationTemplateUrl,
  ): Promise<void> {
    await this.workerImplementation?.addElement({
      index,
      templateFile: join(
        dirname(fileURLToPath(import.meta.url)),
        'assets',
        'station-templates',
        stationTemplateUrl.file,
      ),
    });
  }

  private gracefulShutdown(): void {
    this.stop()
      .then(() => {
        console.info(`${chalk.green('Graceful shutdown')}`);
        // stop() asks for charging stations to stop by default
        this.waitChargingStationsStopped()
          .then(() => {
            exit(exitCodes.succeeded);
          })
          .catch(() => {
            exit(exitCodes.gracefulShutdownError);
          });
      })
      .catch((error) => {
        console.error(chalk.red('Error while shutdowning charging stations simulator: '), error);
        exit(exitCodes.gracefulShutdownError);
      });
  }

  private logPrefix = (): string => {
    return logPrefix(' Bootstrap |');
  };
}