Event Sourcing-CQRS Location Reporter

The Location Reporter microservice files the command to report the new location of a team member.

It acts as the Command Submitter, used by various applications (mobile, web, embedded, etc.) to report the new location of a team member.

The Location Reporter Microservice is part of the StatlerWaldorfCorp Microservices suite, designed for Event Sourcing and CQRS.

This service handles a single command: submitting a location report. It converts commands into events by transforming the command's payload (a request to record a team member's location) into an event that reflects the action has taken place (e.g., member location recorded).

The API for this service is straightforward:

Resource	Method	Description
/api/members/{memberId}/locationreports	POST	Submits a new location report to the service

Why Use the Options Pattern in ASP.NET Core

In ASP.NET Core, the Options pattern is used to manage and configure application settings in a structured and type-safe manner. Here’s why you would use the Options pattern:

Type-Safety

The Options pattern allows you to map configuration settings to strongly-typed objects. This ensures that you get compile-time checking and IntelliSense support in your IDE.

Centralized Configuration

Using options, you can centralize the configuration logic, making it easier to manage and change settings without scattering configuration logic throughout the codebase.

Separation of Concerns

The Options pattern helps to separate configuration from application logic. This makes the code cleaner and easier to maintain.

Dependency Injection

Configuration options can be injected into services or controllers, promoting better design practices and enabling easier unit testing.

Example

Configuration in appsettings.json

{
  "amqp": {
    "Host": "localhost",
    "Port": 5672
  },
  "teamservice": {
    "BaseUrl": "http://teams.example.com",
    "ApiKey": "your-api-key"
  }
}

Define Option Classes

public class AMQPOptions
{
    public string Host { get; set; }
    public int Port { get; set; }
}

public class TeamServiceOptions
{
    public string BaseUrl { get; set; }
    public string ApiKey { get; set; }
}

Configure Options in Program.cs

builder.Services.Configure<AMQPOptions>(builder.Configuration.GetSection("amqp"));
builder.Services.Configure<TeamServiceOptions>(builder.Configuration.GetSection("teamservice"));

Inject Options into Services or Controllers

public class SomeService
{
    private readonly AMQPOptions _amqpOptions;

    public SomeService(IOptions<AMQPOptions> amqpOptions)
    {
        _amqpOptions = amqpOptions.Value;
    }

    // Use _amqpOptions.Host and _amqpOptions.Port as needed
}

This structured approach ensures that configuration settings are managed efficiently, reducing errors and enhancing maintainability.

Accessing API from Swagger

• Run dotnet run --server.urls=http://0.0.0.0:9090
• Access endpoint via Swagger at https://localhost:7190/swagger/index.html

Using curl

$ curl -X 'POST' \
  'https://localhost:7190/api/members/3fa85f64-5717-4562-b3fc-2c963f66afa8/locationreports' \
  -H 'accept: */*' \
  -H 'Content-Type: application/json' \
  -d '{
  "reportId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "origin": "string",
  "latitude": 0,
  "longitude": 0,
  "memberId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
}'