Understanding RPC: An Introduction to gRPC

Understanding RPC: An Introduction to gRPC

Table of Contents:

1. What is gRPC?
2. When should we use gRPC?
3. gRPC's origins and benefits
4. Developing with gRPC
5. Protocol Buffers and its advantages
6. Defining a gRPC service
7. Performance of gRPC
8. How gRPC works
9. Limitations of gRPC
10. Use cases for gRPC
11. Conclusion

What is gRPC?

gRPC is an open-source remote procedure call framework created by Google in 2016. It is a popular implementation of RPC, enabling one machine to invoke code on another machine as if it is a local function call from a user's perspective. gRPC is widely used in connecting large numbers of microservices running within and across data centers.

When should we use gRPC?

gRPC is the preferred mechanism for inter-service communication between microservices in data centers. Its efficiency, performance, and support for multiple programming languages make it a suitable choice for services to select their own language and developer ecosystems. Additionally, gRPC is increasingly used in native mobile clients, providing benefits in energy- and bandwidth-constrained environments.

gRPC's origins and benefits

gRPC was developed by Google as a rewrite of their internal RPC infrastructure, which had been used for years. It has gained popularity due to its thriving developer ecosystem, making it easy to develop production-quality and Type-safe APIs that Scale well. The use of Protocol Buffers as the data interchange format is a Core component of gRPC, providing language-agnostic and platform-agnostic encoding of structured data.

Developing with gRPC

Developers working with gRPC leverage the power of Protocol Buffers schema definitions to generate data access classes for popular programming languages. This allows the creation of both gRPC client and server code from a proto file. The use of generated classes simplifies the process of making RPC calls in the client and fulfilling RPC requests in the server.

Protocol Buffers and its advantages

Protocol Buffers offer several advantages that make them the preferred encoding format for gRPC. They support strongly-Typed schema definitions, allowing the structure of data over the wire to be defined in a proto file. Protocol Buffers provide extensive tooling support for generating data access classes in various programming languages, simplifying the development process.

Defining a gRPC service

A gRPC service is defined in a proto file by specifying RPC method parameters and return types. The same tooling used for generating client and server code from the proto file is used to define the service. This approach allows developers to choose the programming language and ecosystem that best suits their specific use case, which is not usually the case with other RPC frameworks.

Performance of gRPC

The high-performance nature of gRPC can be attributed to two factors. Firstly, Protocol Buffers serve as a highly efficient binary encoding format, outperforming JSON. Secondly, gRPC is built on top of the HTTP/2 protocol, which provides a high-performance foundation at scale. The use of HTTP/2 streams allows for handling multiple concurrent RPC calls over a small number of TCP connections.

How gRPC works

A typical flow from a gRPC client to a gRPC server involves the client invoking the generated client code at build time. This code, known as a client stub, encodes data into Protocol Buffers and sends it to the transport layer as a stream of HTTP/2 data frames. The server receives the packets, decodes them, and invokes the server application. The result is then encoded into Protocol Buffers and sent back to the client application.

Limitations of gRPC

Despite its advantages, gRPC does have limitations. It relies on lower-level access to HTTP/2 primitives, which Current browsers do not provide. While gRPC-Web, a technology that enables making gRPC calls from a browser with the help of a proxy, exists, it is not fully compatible with traditional gRPC and its usage remains limited compared to gRPC.

Use cases for gRPC

gRPC shines in inter-service communication between microservices in data centers. Its support for multiple programming languages allows services to select the language and developer ecosystem that best suits their needs. Additionally, gRPC's efficiency and performance make it a suitable choice for native mobile clients, which often operate in resource-constrained environments.

Conclusion

gRPC is a powerful open-source remote procedure call framework that offers efficient and high-performance inter-service communication between microservices. Its wide adoption is due to its thriving developer ecosystem, the use of Protocol Buffers for data encoding, and support for multiple programming languages. While it may have limitations in certain contexts, gRPC remains a popular choice for scalable and efficient microservice communication.

Highlights:

• gRPC is an open-source remote procedure call framework created by Google.
• It is widely adopted for inter-service communication between microservices in data centers.
• gRPC has a thriving developer ecosystem, making it easy to develop production-quality and type-safe APIs.
• Protocol Buffers serve as the data interchange format for gRPC, offering advantages such as strongly-typed schema definitions and broad tooling support.
• Performance is a key feature of gRPC, as it uses the efficient binary encoding of Protocol Buffers and is built on top of the HTTP/2 protocol.
• gRPC allows for the concurrent handling of multiple RPC calls over a small number of TCP connections.
• Despite its advantages, gRPC has limitations, such as the lack of support for lower-level HTTP/2 primitives in web browsers.
• gRPC is the preferred choice for inter-service communication between microservices in data centers and is increasingly used in native mobile clients.