smartclickhouse/ts/smartclickhouse.classes.smartclickhouse.ts

import * as plugins from './smartclickhouse.plugins.js';
import { TimeDataTable } from './smartclickhouse.classes.timedatatable.js';
import { ClickhouseHttpClient } from './smartclickhouse.classes.httpclient.js';

export interface IClickhouseConstructorOptions {
  url: string;
  database: string;
  username?: string;
  password?: string;
  /**
   * allow services to exit when waiting for clickhouse startup
   * this allows to leave the lifecycle flow to other processes
   * like a listening server.
   */
  unref?: boolean;
}

export class SmartClickHouseDb {
  public options: IClickhouseConstructorOptions;
  public clickhouseClient: ClickhouseHttpClient;

  constructor(optionsArg: IClickhouseConstructorOptions) {
    this.options = optionsArg;
  }

  /**
   * starts the connection to the Clickhouse db
   */
  public async start(dropOld = false) {
    console.log(`Connecting to default database first.`);
    // lets connect
    this.clickhouseClient = await ClickhouseHttpClient.createAndStart(this.options);
    await this.pingDatabaseUntilAvailable();
    console.log(`Create database ${this.options.database}, if it does not exist...`);
    await this.createDatabase(dropOld);
  }

  public async createDatabase(dropOld: boolean = false) {
    if (dropOld) {
      await this.clickhouseClient.queryPromise(`DROP DATABASE IF EXISTS ${this.options.database}`);
    }
    await this.clickhouseClient.queryPromise(`CREATE DATABASE IF NOT EXISTS ${this.options.database}`);
  }

  public async pingDatabaseUntilAvailable() {
    let available = false;
    while(!available) {
      available = await this.clickhouseClient.ping().catch(err => {
        return false;
      });
      if (!available) {
        console.log(`NOT OK: tried pinging ${this.options.url}... Trying again in 5 seconds.`);
        await plugins.smartdelay.delayFor(5000, null, this.options.unref);
      }
    }
  }

  /**
   * gets a table
   */
  public async getTable(tableName: string) {
    const newTable = TimeDataTable.getTable(this, tableName);
    return newTable;
  }
}