cosmos-provider

$npx mdskill add dotnet/efcore/cosmos-provider

Enables integration of Entity Framework Core with Azure Cosmos DB for document database operations

  • Automatically initializes an Azure Cosmos DB emulator for testing purposes.
  • Deploys and manages a Cosmos DB instance via EF Core's `EnsureCreated()` method.
  • Handles JSON serialization/deserialization for documents, simplifying complex data structures.
  • Uses ETags for optimistic concurrency control in document operations.

SKILL.md

.github/skills/cosmos-providerView on GitHub ↗
---
name: cosmos-provider
description: 'Implementation details for the EF Core Azure Cosmos DB provider. Use when changing Cosmos-specific code.'
user-invocable: false
---

# Cosmos DB Provider

Non-relational provider with its own parallel query pipeline. Uses JSON for document materialization.

## Key Differences from Relational

- No migrations — use `EnsureCreated()`
- Documents as JSON — owned and complex types become embedded objects
- Partition key configuration required for performance
- `ETag` for optimistic concurrency
- No cross-container joins

## Azure Cosmos DB Emulator for Tests

- `TestEnvironment.InitializeAsync()` auto-starts a `Testcontainers.CosmosDb` container when `Test__Cosmos__DefaultConnection` is not set. Set the env var to use an existing emulator instead.
- Skip tests requiring unsupported features on the Linux emulator with ` [ConditionalFact(typeof(CosmosTestEnvironment), nameof(CosmosTestEnvironment.IsNotLinuxEmulator))]`.

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