Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/chatthana/cqrs-event-sourcing-example

An example project for CQRS & Event Sourcing on Typescript
https://github.com/chatthana/cqrs-event-sourcing-example

cqrs ddd denormalization domain-driven-design event-driven-architecture event-sourcing eventstoredb kafka microservices nodejs opentelemetry typescript

Last synced: 8 days ago
JSON representation

An example project for CQRS & Event Sourcing on Typescript

Awesome Lists containing this project

README 

        
# Event Sourcing with EventStoreDB



This is an example project demonstrating the implementation of event-sourced inventory application with EventStoreDB as an event store



### DISCLAIMER!



> I can not guarantee universally accepted practises and whatever demonstrated in this project is solely based on my taste. If you find this project useful, take a moment and discuss with your team whether this is applicable for them!



## Architecture Overview



The application leverages Event Sourcing with EventStoreDB as the central event store. Events are published to Kafka for asynchronous processing and consumption by other services. A denormalised view of the data is maintained in MongoDB for efficient querying. Distributed tracing is provided by Jaeger, and Redis is available for caching.



## Services



The project comprises the following services:



**Core Application Services (defined in `docker-compose-app.yml`):**



- **webapi:** The main application API, interacting with EventStoreDB and Kafka. Exposes port 3000 (Configurable).

- **snapshot-subscriber:** Creates and maintains snapshots from EventStoreDB events for optimised read model generation.

- **esdb-kafka-publisher:** Publishes events from EventStoreDB to Kafka.

- **denormaliser:** Consumes events from Kafka and updates the MongoDB database.

- **eventbus:** A generic event bus service based on Kafka.



**Supporting Infrastructure Services (defined in `docker-compose.yml`):**



- **EventStoreDB:** The core event store. Configured for single-node operation with standard projections enabled. Uses insecure HTTP for development/testing simplicity. Exposes port 2113. Persistent data and logs are stored in named volumes. Uses an Arm64 compatible image.

- **Kafka:** Asynchronous messaging backbone for inter-service communication. ZooKeeper is used for coordination. Exposes ports 9092 and 29092.

- **ZooKeeper:** Coordination service for Kafka. Exposes port 2181.

- **MongoDB:** Stores the denormalised data for efficient querying. Exposes port 27017. Persistent data is stored in a named volume.

- **Redis:** Available for caching. Exposes port 6379.

- **Jaeger:** Provides distributed tracing for monitoring and troubleshooting. Exposes ports 4317, 4318, and 16686.



## Running the Project



1. **Prerequisites:** Ensure you have Docker and Docker Compose installed.

2. **Start the services:** Navigate to the project directory and run `docker-compose up -d`. The `-d` flag runs the containers in detached mode.



## Configuration and Key Considerations



- **Development Focus:** The configuration prioritises ease of setup for a development/testing environment. **Important:** Security settings are relaxed and not suitable for production.

- **Insecure EventStoreDB and Kafka:** Both EventStoreDB (`EVENTSTORE_INSECURE=true`) and Kafka (`PLAINTEXT` security protocol) are configured insecurely. These settings **must** be changed for production deployments.

- **Arm64 Support:** EventStoreDB uses an image specifically built for Arm64 architecture. The other images are assumed to be multi-architecture.

- **Networking:** All services operate on the same Docker network named `esdb-ts`.

- **Data Persistence:** EventStoreDB and MongoDB use named volumes to persist data across container restarts.



## Shutting down



To stop the services and remove the containers, run `docker-compose down`. Note that data in the named volumes will be preserved.