https://github.com/morzhanov/go-event-sourcing

Go CQRS + Event Sourcing example application
https://github.com/morzhanov/go-event-sourcing

Last synced: 5 days ago
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Go CQRS + Event Sourcing example application

• Host: GitHub
• URL: https://github.com/morzhanov/go-event-sourcing
• Owner: morzhanov
• Created: 2021-10-10T12:56:39.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2021-10-12T18:15:47.000Z (about 3 years ago)
• Last Synced: 2024-11-08T00:52:36.480Z (about 2 months ago)
• Language: Go
• Size: 60.5 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Go Event Sourcing Example

Go CQRS + Event Sourcing example application.

## CQRS and Event Sourcing



CQRS stands for Command and Query Responsibility Segregation, a pattern that separates read and update operations for a data store. Implementing CQRS in your application can maximize its performance, scalability, and security. The flexibility created by migrating to CQRS allows a system to better evolve over time and prevents update commands from causing merge conflicts at the domain level.

Event sourcing persists the state of a business entity such an Order or a Customer as a sequence of state-changing events. Whenever the state of a business entity changes, a new event is appended to the list of events. Since saving an event is a single operation, it is inherently atomic. The application reconstructs an entity’s current state by replaying the events.

Nice article on Event Sourcing.



## Project Architecture



- Orders - service for order creation and retrieval

    - Commands used for order creation and processing

    - Queries used for orders retrieval

- Processor - dumb service which mocks order processing

- Command store - persists commands (MongoDB)

- Query store - consumes events from kafka commands channel and saves/updates data for queries (PostgreSQL)

- Kafka - used as communication level between Command-Query stores and Order-Processor services

## Running

1. `cd /deploy`

2. `docker-compose up -d`

3. `cd ../`

4. `go run cmd/processor/main.go`

5. `go run cmd/orders/main.go`

After that you'l be able to run commands and queries.

## Commands

### Create Order

```bash

curl --location --request POST '127.0.0.1:8080' \

--header 'Content-Type: application/json' \

--data-raw '{

    "id": "someid",

    "name": "somename",

    "status": "new"

}'

```

### Process Order

```bash

curl --location --request POST '127.0.0.1:8080/someid' --data-raw ''

```

## Queries

### Get Orders

```bash

curl --location --request GET '127.0.0.1:8080'

```

### Get Order

```bash

curl --location --request GET '127.0.0.1:8080/someid'

```