# qcon-microservices

**Repository Path**: mirrors_confluentinc/qcon-microservices

## Basic Information

- **Project Name**: qcon-microservices
- **Description**: Example online orders app composed of event-driven microservices. Built for QCon workshop.
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-24
- **Last Updated**: 2026-05-23

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# qcon-microservices
Example online orders app composed of event-driven microservices. Built for QCon workshop.

## Slides: 
https://drive.google.com/file/d/1vq1tcLk4FWK7BKRG5cEhOzbeXoy65hUK/view

## This workshop will include:

- Create a Kafka cluster on Confluent Cloud
- Create topics, produce and consume events from commandline
- Using Kafka consumer and producer in a microservice to perform simple order validation.
- Implement a webservice that submits orders and uses "read-own-writes" pattern to show order status.
- Use Streams-to-Table join to send status updates by email.


## Preparation!

## Make sure you have the following:
- OSX or Linux
- Java 8
- Java development environment (Intellij recommended)
- Maven

### Please create cloud clusters for the workshop!

1. Login to https://confluent.cloud with username and password you received by email from QCon.
2. Create a new cluster! call it “lastname-firstname”, make sure you
use the smallest options, create it on Google Cloud Platform and use
us-centeral1 region. You'll be shown the cost for the cluster. Don't
worry about it - Confluent has been kind enough to sponsor the
clusters and you will not be charged.
3. Follow the on-screen instructions closely to install Confluent
Cloud CLI and initialize the CLI.
4. If you ran into issues, try to refer to the documentation here:
https://docs.confluent.io/current/quickstart/cloud-quickstart.html.
5. If you managed to create a cluster, follow Step 3 of the Quickstart
(https://docs.confluent.io/current/quickstart/cloud-quickstart.html)
to create a topic and produce/consume some events.

### In addition:
1. Please clone this repository
2. Run `mvn dependency:resolve` to get dependencies in advance. This will help with the network in the class.


## Outline

1. **Lesson 0:** Introduction to Kafka, topics and events:
    - What are event-driven microservices and why do we need them?
    - Overview of our Architecture
    - Key concepts of Apache Kafka
2. **Lab 0:** 
    - Create a cluster in Confluent Cloud
    - Install the Confluent Cloud CLI
    - Create topic, produce and consume events from Cloud CLI
3. **Lesson 1:** Simple event validation:
    - "Hipster Stream Processing"
    - Producer and Consumer APIs
4. **Lab 1:** 
    - `git checkout lab1`
    - Create topic `orders` with 3 partitions
    - Validate events and produce results to Kafka: Implement the TODO part of the OrderDetailsService. Note that `validate()` method implements the specific validation rules.
    - Build the service :) using `mvn clean install`
    - Test the simple validation service: Either using `scripts/run_lab1.sh`, writing a unit test, or a different method.
    - **Extra credit:** Use a produce method with error handling.
    - **Extra credit:** How would you use a rules engine?
    - **Extra credit:** How would you add multiple validators?
5. **Lesson 2:** CQRS-based web-service with Kafka Streams
    - Introduction to Kafka Streams
    - Introducing local materialized views
    - Stream-table duality
    - Code review of web-service
6. **Lab 2:**
    - `git checkout lab2`
    - Run and experiment with web service:
        - Build the service :) using `mvn clean install`        
        - Use `scripts/run_lab2.sh` to experiment with the service. Running the script will start the Order service and validation service. Pressing any key will run few pre-canned `curl` commands that use the service. Another click will cause the services to exit.
    - Add "check for validation" endpoint: Implement the TODO part of the OrderService. Note that we already have a simple GET endpoint that gets any order, we need a new endpoint that only returns validated orders.
    - Use the same script from earlier to experiment with the new endpoint.
    - **Extra Credit**: Implement blocking-POST that only returns after order was validated.
    - **Extra Credit:** How would you scale to multiple instances? (Hint: Look up interactive queries APIs for Kafka Streams)
7. **Lesson 3** (if there is time): Simple email service
    - Stream-table join enrichment pattern
    - Global KTables
8. **Lab 3** (if there is time):
    - `git checkout lab3`
    - Implement Stream-table join: Implement the two functions required for the join (marked as TODO)
    - Test email service using the CustomerProducer and OrderProducer clases:
       - Build the service :) using `mvn clean install`  
       - Create a new topic `CUSTOMERS` for customer data
       - `scripts/run_lab3.sh` will run the data generators, validator and email service
       - You can write additional tests