Software-Engineering

gRPC (gRPC Remote Procedure Call)

What is gRPC?

gRPC is a high-performance, open-source universal RPC framework developed by Google. It allows a client application to directly call a method on a server application on a different machine as if it were a local object. It is based on the HTTP/2 protocol and uses Protocol Buffers (Protobuf) as its interface description language and data serialization format.

How it Works

gRPC follows the RPC (Remote Procedure Call) model.

1. Protocol Buffers (Protobuf): You define the service and the structure of the payload in a .proto file. This is a language-neutral way to serialize structured data.
2. Code Generation: Using the protoc compiler, you generate client and server code in your preferred languages (Go, Java, Python, etc.) from the .proto definition.
3. HTTP/2 Transport: gRPC uses HTTP/2 under the hood, which supports:
   • Multiplexing: Multiple requests over a single TCP connection.
   • Binary Framing: Data is sent in binary, not text (like JSON), making it much smaller and faster to parse.
   • Streaming: Supports bi-directional streaming (client-side, server-side, or both).

Why We Need It & When to Use

gRPC is designed for low latency and high throughput communication, primarily between microservices.

Use gRPC when:

• Microservices Communication: Internal service-to-service calls where milliseconds matter.
• Polyglot Environments: You have services written in different languages that need to talk to each other efficiently.
• Streaming: You need real-time streaming of data (e.g., voice, video, telemetry).
• Low Bandwidth: IoT devices or mobile networks where data size is critical.

Other Options

• REST: Better for public-facing APIs and browser clients (browsers don’t fully support gRPC yet without a proxy like gRPC-Web).
• GraphQL: Better for flexible data querying from the frontend.

Pros and Cons

Pros

• Performance: Protobuf binary serialization is significantly faster and smaller than JSON. HTTP/2 multiplexing reduces latency.
• Strict Contract: The .proto file enforces a strict interface, reducing integration errors.
• Code Generation: Automatically generates idiomatic client/server stubs, saving development time.
• Streaming Support: Native support for streaming is a game-changer for certain applications.

Cons

• Browser Support: Browsers do not support gRPC directly. You need a proxy (gRPC-Web) to use it from a web frontend.
• Debuggability: Binary data is not human-readable. You need special tools to inspect traffic, unlike JSON which you can just read.
• Learning Curve: Requires learning Protocol Buffers and the RPC paradigm, which is different from the familiar REST.