Add customer projection service and event processor

[ambvdijk]

Introduces MathMax.Administration.Projections.Customer project for handling customer event projections. Adds background services for consuming NATS events and updating PostgreSQL, configuration settings, and registers the new project in the solution file.

[Copilot]

Pull Request Overview

Adds a new Customer projections service project to consume events from NATS and update a PostgreSQL database.

• Introduces MathMax.Administration.Projections.Customer project and registers it in the solution
• Implements CustomerProjectionService to pull events from JetStream and post to a bounded channel
• Implements CustomerEventProcessor to read from the channel and upsert records in PostgreSQL

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
MathMax.EventSourcing.sln	Registers new project and adds platform configurations
ProjectionSettings.cs	Defines configuration POCO for NATS and Postgres
Program.cs	Sets up DI, hard-coded settings, and background hosts
MathMax.Administration.Projections.Customer.csproj	References required packages and projects
CustomerProjectionService.cs	Background service that pulls and filters NATS events
CustomerEventProcessor.cs	Background service that upserts customer records

Comments suppressed due to low confidence (3)

MathMax.Administration.Projections.Customer/CustomerProjectionService.cs:13

• [nitpick] Consider adding unit and integration tests for CustomerProjectionService to verify deserialization, branching logic, and backpressure handling.

public class CustomerProjectionService : BackgroundService

MathMax.Administration.Projections.Customer/ProjectionSettings.cs:3

• [nitpick] Public settings class lacks XML documentation. Adding <summary> comments on the class and its properties will improve discoverability when binding and using ProjectionSettings.

public class ProjectionSettings

MathMax.Administration.Projections.Customer/Program.cs:25

• The call to Channel.CreateBounded<EventEnvelope> requires using System.Threading.Channels; and you also need using MathMax.EventSourcing; for EventEnvelope. Add these usings at the top of Program.cs so the code compiles.

                services.AddSingleton(Channel.CreateBounded<EventEnvelope>(100));

[Copilot]

Hard-coding the database connection string (including credentials) is insecure. Consider moving this into configuration files or environment variables and binding it via IConfiguration.

Suggested change

	services.AddSingleton<ProjectionSettings>(new ProjectionSettings
	{
	NatsUrl = "nats://localhost:4222",
	StreamName = "EVENTS",
	ConsumerName = "projection-consumer",
	Subject = "events.>",
	PostgresConnectionString = "Host=localhost;Username=postgres;Password=yourpassword;Database=yourdb"
	services.AddSingleton<ProjectionSettings>(provider =>
	{
	var configuration = provider.GetRequiredService<IConfiguration>();
	return new ProjectionSettings
	{
	NatsUrl = "nats://localhost:4222",
	StreamName = "EVENTS",
	ConsumerName = "projection-consumer",
	Subject = "events.>",
	PostgresConnectionString = configuration.GetConnectionString("PostgresConnection")
	};

[Copilot]

[nitpick] Using Console.WriteLine prevents structured logging and makes it hard to control output. Inject an ILogger<CustomerProjectionService> and use _logger.LogError(...) instead.

[Copilot]

[nitpick] Replace Console.WriteLine with a structured ILogger<CustomerEventProcessor> for better diagnostics and control over log levels.