ag2ai/faststream
Faststream
FastStream is an asyncio message broker framework for building event-driven applications in Python. It provides a unified interface and a multi-broker messaging abstraction layer that translates generic producer and consumer calls into broker-specific APIs.
The framework features a built-in dependency injection container and uses decorators to route messages to asynchronous handler functions. It includes a documentation generator that extracts channel definitions and message formats from code to produce standardized AsyncAPI specifications.
The project supports integration with Kafka, RabbitMQ, Redis, and MQTT, covering capabilities such as horizontal consumer grouping, pluggable data serialization, and in-memory broker simulation for testing. It also allows for the integration of message handlers with web frameworks to share lifecycle management and dependencies.
Features
- Message Brokers - Provides a Python framework for building event-driven applications with type-safe message handlers and multi-broker support.
- Messaging Broker Emulators - Tests message handlers offline using an in-memory broker simulation.
- AsyncAPI Generators - Generates AsyncAPI documentation directly from message handler code and schema definitions.
- Generators - Generates interactive AsyncAPI documentation from handler code and serves it via HTTP.
- CLI Application Launchers - Launches event-driven applications from the command line with hot reload and worker scaling.
- Event-Driven Application Launchers - Launches event-driven applications from the command line with development features.
- Event-Driven Application Launchers - Provides a CLI launcher with hot reload and multi-worker scaling for developing event-driven applications.
- Broker Integrations - Integrates with multiple message brokers to publish and consume events asynchronously in event-driven applications.
- Lifecycle Embeddings - Embeds broker lifecycle into any async web framework for seamless startup and shutdown.
- Web Framework Lifecycle Integrations - Embeds message brokers into any HTTP web application with separate lifecycle management.
- Message Subscription Management - Subscribes to message queues and processes each incoming message with a handler function.
- Broker Abstractions - Provides a unified abstraction layer that decouples message producers and consumers from specific broker implementations.
- API Documentation Generators - Automatically generates interactive AsyncAPI documentation from handler code.
- Type-Annotation Validation - Validates message payloads against Python type annotations for data integrity.
- Dependency Injection Containers - Provides a dependency injection container that injects handler arguments from a global context.
- Message Payload Validators - Validates both incoming and outgoing messages against defined schemas automatically.
- Microservices Development - Builds microservices that communicate asynchronously through message brokers.
- In-Memory Broker Stubs - Provides an in-memory broker stub for testing message handlers without a live broker.
- Declarative Handlers - Ships a declarative system for defining message subscribers using type annotations and dependency injection.
- Decorator-Based Definitions - Defines functions that consume messages from queues, transform data, and produce results using decorators.
- AsyncAPI Schema Generators - Generates AsyncAPI documents from message handler code and schemas.
- Message Queue Registrations - Registers message broker subscribers as route handlers alongside HTTP endpoints in web applications.
- Decorator-Based Dispatchers - Uses decorators to bind functions to message queues and process incoming events.
- Subject Subscription Filtering - Subscribes to subjects using wildcard patterns to create flexible topic hierarchies.
- Consumer Group Coordinators - Distributes messages across consumer groups using queue groups for load-balanced horizontal scaling.
- Web Framework Broker Lifecycle Embeddings - Embeds message broker lifecycle into web applications for unified APIs.
- Web Framework Lifecycle Embeddings - Embeds broker lifecycle into async web frameworks for combined HTTP and message handling.
- At-Least-Once Delivery Guarantees - Persists messages in a durable store to survive restarts and failures, ensuring at-least-once delivery.
- Declarative Stream Processing - Processes streaming events by consuming messages and publishing responses using declarative decorators.
- HTTP-Triggered Publications - Sends messages to the broker from any HTTP route using context injection.
- Router Attachments - Attaches a message broker router to any web application, combining HTTP and queue handlers.
- AsyncAPI Documentation Hosting - Serves interactive AsyncAPI documentation endpoints for message-driven APIs.
- Messaging - Framework for building services over Kafka, RabbitMQ, and more.
