Description

ClickHouse® is an open-source, high performance columnar OLAP database management system for real-time analytics using SQL.

Installation

Install the following package:

$ npm i --save @depyronick/clickhouse-client

Quick Start

• Importing the module
• Methods
  • ClickHouseClient.query<T>(query: string): Observable<T>
  • ClickHouseClient.queryPromise<T>(query: string): Promise<T[]>
  • ClickHouseClient.insert<T>(table: string, data: T[]): Observable<any>
  • ClickHouseClient.ping(timeout: number = 3000): Promise<boolean>
• Notes

Importing the module

Once the installation process is complete, you can import the ClickHouseClient

const { ClickHouseClient } = require('@depyronick/clickhouse-client');

// or:
// import { ClickHouseClient } from '@depyronick/clickhouse-client';

const analyticsServer = new ClickHouseClient({
  host: '127.0.0.1',
  password: '7h3ul71m473p4555w0rd'
});

// you can create multiple clients
const chatServer = new ClickHouseClient({
  host: '127.0.0.2',
  password: '7h3ul71m473p4555w0rd'
});

new ClickHouseClient(options: ClickHouseOptions) will create a ClickHouse client with the specified connection options.

See ClickHouseOptions object for more information.

Methods

ClickHouseClient.query<T>(query: string): Observable<T>

this.analyticsServer.query('SELECT * FROM visits LIMIT 10').subscribe({
  error: (err) => {
    // called when an error occurred during query
  },
  next: (row) => {
    // called for each row
  },
  complete: () => {
    // called when stream is completed
  }
});

ClickHouseClient.queryPromise<T>(query: string): Promise<T[]>

this.analyticsServer
  .queryPromise('SELECT * FROM visits LIMIT 10')
  .then((rows) => {
    // all retrieved rows
  })
  .catch((err) => {
    // called when an error occurred during query
  });

// or

const rows = await this.analyticsServer.queryPromise(
  'SELECT * FROM visits LIMIT 10'
);

ClickHouseClient.insert<T>(table: string, data: T[]): Observable<any>

The insert method accepts two inputs.

• table is the name of the table that you'll be inserting data to.
  • Table value could be prefixed with database like analytics_db.visits.
• data: T[] array of JSON objects to insert.

analyticsServer
  .insert('visits', [
    {
      timestamp: new Date().getTime(),
      ip: '127.0.0.1',
      os: 'OSX',
      userAgent:
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/95.0.4638.69 Safari/537.36',
      version: '1.0.0'
    }
  ])
  .subscribe({
    error: (err) => {
      // called when an error occurred during insert
    },
    next: () => {
      // currently next does not emits anything for inserts
    },
    complete: () => {
      // called when insert is completed
    }
  });

ClickHouseClient.ping(timeout: number = 3000): Promise<boolean>

The ping method accepts one input.

• timeout is the time in milliseconds to wait for the server to send ping response Ok.\n

// if you're using async/await
const ping = await analyticsServer.ping();

// or

analyticsServer
  .then((pingResult) => {
    // ping result is a boolean
    // it will return `true` if we were able to receive `Ok.\n`
    // and `false` if anything but `Ok.\n`
  })
  .catch((reason) => {
    // reason is the full response of the error
    // see more details at https://axios-http.com/docs/handling_errors
  });

Notes

• This repository will be actively maintained and improved.
• Currently only supports JSON format.
  • Planning to support all applicable formats listed here.
• Planning to implement TCP protocol, if ClickHouse decides to documentate it.
• Planning to implement inserts with streams.
• This library supports http response compressions such as brotli, gzip and deflate.

Stay in touch

• Author - Ali Demirci

License

MIT licensed.