SaanSoft.Cqrs

Lightweight CQRS and Event Sourcing implementation for C#

Status

Documentation

Todo...

• event source vs event stream vs event driven
• cqrs
• glossary
• index with links to implemented decorators (instead of in this file)

TODO

IInMemory***Bus for publishers

• tryExecute / queue / fetch

all messages - attribute to have 3rd party queue group name (for aws/azure/etc)

Features

• Replay events
• replay events for new handlers

Decorators

• ✅ Store - Store messages, and optionally their publisher and handlers
• ✅ ILogger Scope
  • Ensure useful structured logging by adding ILogger.BeginScope with message metadata
• ✅ Ensure CorrelationId
• Encryption / Decryption
• retry with polly

Message Repository

• ✅ MongoDB implementation
• AWS DynamoDB (maybe, plus example app if doing)
• Azure Cosmos DB (maybe, plus example app if doing)

Message Buses

• ✅ In Memory
• AWS SNS/SQS
• Azure Topics and Queues (maybe, plus example app if doing)

DI frameworks

• 👀 c# IServiceCollection
• SimpleInjection

Examples

Shared api and messaging functionality

👀

Users

• User - {Key, Name}
• CRUD

TodoList

• TodoItem - {Key, Title, Order, AssignedTo?=User, Status=New|InProgress|Done}
  • Add/edit/delete
  • AssignToUser
  • UpdateStatus
  • UpdateOrder
• TodoList - {Key, Title}
  • Add/edit/delete
  • Get all lists
  • Get all lists with items assigned to user
  • Get by list Key
• Maybe in future
  • Add an image to the TodoItem, see how its dealt with in upload and message processing

Basic InMemory Api

• in memory messaging
• no decorators
• no message store
• MongoDB for read model for queries

Api endpoint tests

• Run Api in Github Actions CI
  • Will eventually want to run a test matrix of Api tests
• Run same tests against each example Api to ensure functionality is the same from a users perspective
  • Specflow + Playwright
• Enrich each test matrix to ensure decorators/db/etc are working

MongoDB Store Api

• in memory messaging
• all the decorators
• mongodb repositories
• use messages to build read model in queries
• diagnostic/info flowchart of messages
  • filter by
    • to from date
    • message full type name
    • correlation id
    • assembly for publisher/handler??
    • has error
  • return mermaid text from api
  • maybe svelvet for ui
• Use docker compose local dev and GitHub CI infrastructure

Aws Lambda Api and SNS/SQS handlers

• Aws SNS/SQS messaging
• all the decorators except stores
• queries read model from ??
• Use LocalStack for local dev and GitHub CI infrastructure
  • Docker compose