Building Modern Services with .NET Core 3 and gRPC Greg Shackles VP of Technology, Olo @gshackles [email protected] 

What Are Worker Services? ▪ Long-running background applications ▪ Some examples: – Queue processor – Event stream processor – Timer-based tasks 

Creating A Worker Service > dotnet new worker 

Hosted Services 

Lifetime Management Microsoft.Extensions.Hosting.Internal.ConsoleLifetime Microsoft.Extensions.Hosting.WindowsServices.WindowsServiceLifetime Microsoft.Extensions.Hosting.Systemd.SystemdLifetime 

Demo: Worker Services github.com/gshackles/aspnetcore-grpc-demo: samples/RangersPlayoffStatusChecker 

Introduction to gRPC 

What is gRPC? ▪ High performance, open source remote procedure call framework – Action-centric vs resource-centric ▪ Cross-platform, supported everywhere in many languages ▪ Automatically generate client SDKs from IDL 

What is gRPC? ▪ Protocol buffers used for interface definitions and serialization – Compact, efficient binary format – Fast serialization and deserialization – Downside: less human-readable ▪ Built on HTTP/2 – Binary framing and compression: more efficient protocol than HTTP 1.x – Multiplexing: stream multiple calls over a single TCP connection – Flow control: prevent senders from overwhelming receivers 

Protobuf Primer 

Creating A gRPC Service > dotnet new grpc 

Service Definition 

Making Remote Procedure Calls From C# 

Unary RPC 

Server Streaming RPC 

Client Streaming RPC 

Bidirectional Streaming RPC 

Authentication and Authorization 

Deadlines and Cancellations 

Interceptors and Middleware 

Client Factory and Context Propagation 

Health Checks 

Health Checks 

Error Handling 

Server Reflection 

Demo: gRPC Services github.com/gshackles/aspnetcore-grpc-demo: samples/HockeyStandings 

Questions? github.com/gshackles/aspnetcore-grpc-demo