Introduction to gRPC

• gRPC: An open-source remote procedure call framework by Google (2016)
  • A rewrite of Google's internal RPC infrastructure

What is RPC?

• Remote Procedure Call (RPC):
  • Allows code invocation on a different machine as if it were a local function call.
  • gRPC is a popular RPC implementation.

Why gRPC?

Popularity Factors:

1. Developer Ecosystem:

   • Facilitates development of production-quality, type-safe APIs.
   • Scales well for connecting microservices within and across data centers.

2. Protocol Buffers:

   • Data interchange format for gRPC.
   • Language-agnostic and platform-agnostic.
   • Supports strongly-typed schema definitions in proto files.
   • Tools available to generate data access classes for popular languages.

3. Performance:

   • Efficient binary encoding format faster than JSON.
   • Built on HTTP/2 for high performance.
   • Allows multiple message streams over a single TCP connection via HTTP/2.

gRPC Implementation Example

• Order Service (client) to Payment Service (server):
  • Client invokes gRPC client code (client stub).
  • Data encoded in Protocol Buffers and sent over HTTP/2.
  • Server decodes data, processes request, encodes response in Protocol Buffers.
  • Response sent back over HTTP/2, client decodes and uses result.

Limitations and Challenges

• Web Clients and Servers:
  • Browsers lack necessary HTTP/2 primitive access.
  • Can use gRPC-Web with proxies for browser compatibility.

When to Use gRPC

• Inter-service Communication:

  • Preferred in microservices within data centers.
  • Supports multiple programming languages for diverse ecosystems.

• Mobile Clients:

  • Efficient for energy and bandwidth-constrained environments.

Conclusion

• gRPC is powerful for certain use cases, particularly in data centers and mobile.
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