@stryker-mutator/core/src/logging/logging-server.ts

The extendable JavaScript mutation testing framework

import { coreTokens } from '../di/index.js';
import { LoggingEvent, SerializedLoggingEvent } from './logging-event.js';
import { LoggingSink } from './logging-sink.js';
import net from 'node:net';
import { Disposable } from '@stryker-mutator/api/plugin';
import { promisify } from 'node:util';
import { LogLevel } from '@stryker-mutator/api/core';

export interface LoggingServerAddress {
  port: number;
}

export const DELIMITER = '__STRYKER_CORE__';

export class LoggingServer implements Disposable {
  static readonly inject = [coreTokens.loggingSink] as const;
  #server;

  constructor(private readonly loggingSink: LoggingSink) {
    this.#server = net.createServer((socket) => {
      socket.setEncoding('utf-8');
      let dataSoFar = '';
      socket.on('data', (data: string) => {
        dataSoFar += data;
        let index;
        while ((index = dataSoFar.indexOf(DELIMITER)) !== -1) {
          const logEvent: SerializedLoggingEvent = JSON.parse(
            dataSoFar.substring(0, index),
          );
          dataSoFar = dataSoFar.substring(index + DELIMITER.length);
          this.loggingSink.log(LoggingEvent.deserialize(logEvent));
        }
      });
      socket.on('error', (error) => {
        this.loggingSink.log(
          LoggingEvent.create(LoggingServer.name, LogLevel.Debug, [
            'An worker log process hung up unexpectedly',
            error,
          ]),
        );
      });
    });
  }

  public listen() {
    return new Promise<LoggingServerAddress>((res) => {
      this.#server.listen(() => {
        res({ port: (this.#server.address() as net.AddressInfo).port });
      });
    });
  }

  public async dispose() {
    await promisify(this.#server.close).bind(this.#server)();
  }
}