Introduction | Kurrent Docs
Skip to main content

Introduction

Introduction

This tutorial will guide you through the Outbox Out of the Box sample with KurrentDB using GitHub Codespaces.

Objectives

In this tutorial, you will:

  • Understand how triggering events in KurrentDB can initiate updates to external data stores
  • Implement persistent subscriptions to process events from KurrentDB streams
  • Observe real-time event processing with persistent subscriptions
  • Create and configure consumer groups for reliable event processing
  • Develop idempotent event handlers to safely process events with at-least-once delivery guarantees
  • Implement proper error handling strategies for both transient and permanent errors
  • Work with checkpoints to ensure events are properly processed after system failures
  • Learn how to handle problematic events by using techniques like retrying and skipping

Prerequisites

Before starting, ensure you have the following:

  • A GitHub account to use GitHub Codespaces
  • Basic knowledge of c#
  • Familiarity with command-line operations

Tutorial Overview

This tutorial consists of the following steps:

Part 1: Set up Codespaces

  1. Set up your Codespaces: Starts up an interactive coding environment in your browser where all tools and databases are installed

Part 2: Trigger Writes to External Data Stores

  1. Start Databases and Append OrderPlaced Event to KurrentDB: Start up KurrentDB and PostgreSQL, and append sample OrderPlaced events
  2. Browse OrderPlaced Events in KurrentDB's Admin UI: Access the Admin UI to explore the triggering events

Part 3: Write to a External Data Store with Persistent Subscription

  1. Create a KurrentDB Persistent Subscription Consumer Group: Set up a persistent subscription to process events
  2. Review the Consumer Group from KurrentDB Admin UI: Examine the created consumer group
  3. Start the Order Processor Application: Run the application that processes OrderPlaced events
  4. Examine the Order Processor Application Codebase: Understand how idempotent event processing works
  5. Process New Events in Real-Time: Observe real-time event processing with persistent subscriptions

Part 4: Error Handling of Writes to External Data Stores

  1. Handle Application Outage with Checkpoints: Learn how checkpoints ensure event processing after system failures
  2. Handle Transient Errors by Retrying Events: Implement retry logic for temporary failures
  3. Examine How Transient Errors are Handled in the Codebase: Understand the error handling implementation
  4. Handle Permanent Errors by Skipping Events: Learn to handle unrecoverable errors by skipping problematic events
  5. Examine How Permanent Errors are Handled in the Codebase: Review the permanent error handling implementation
Last Updated: