Vulthil.SharedKernel.Infrastructure.Cosmos

Use Vulthil.SharedKernel.Infrastructure.Cosmos to run the shared infrastructure (including outbox) against Azure Cosmos DB.

When to use

• Cosmos DB is the underlying store for an application's primary DbContext
• Aspire-wired Cosmos connection via AddCosmosDbContext
• Outbox processing should use the Cosmos-specific strategy (transactional batches per partition rather than relational locking)

Pattern

• Call UseCosmosDb("connectionStringKey") on the database infrastructure configurator – it both registers the EF Core context and selects the Cosmos outbox strategy
• Configure the Cosmos-specific entity model for OutboxMessage via the ApplyCosmosOutbox() model-builder extension (call it from your OnModelCreating)
• Order between UseCosmosDb and EnableOutboxProcessing does not matter; the configurator defers the underlying call until the full chain has executed

Usage

Registration

builder.AddDbContext<AppDbContext>(config => config
    .UseCosmosDb("Cosmos", settings =>
    {
        settings.DatabaseName = "app";
    })
    .EnableOutboxProcessing(o =>
    {
        o.BatchSize = 20;
        o.MaxRetries = 3;
    }));

Notes on Cosmos behavior

• The Cosmos outbox strategy uses Cosmos transactional batches, which require all participating documents to share a partition key. If you customize the outbox entity configuration, keep the partition key choice consistent with how messages are produced.
• Migrations do not apply to Cosmos – use EnsureCreatedAsync<AppDbContext>() instead of MigrateAsync<AppDbContext>() during development setup.