Getting Started With GRPC in .NET

Intro

1. What is gRPC?
   • RPC Framework
   • vs. REST
     • Binary vs. human-readable serialization
     • No HTTP verb nomenclature
     • Shared contract
     • Requires special tooling
2. HTTP2
   • multiplexing / streaming
   • One connection, multiple bi-directional requests/responses
3. Companies that use it:
   • Uber, Netflix, Spotify, DropBox
4. Cross-platform
   • Supported languages: Documentation | gRPC

Demo

Creating Server

1. Run Server Setup Script

2. Open sln

3. Add to appsettings.json (this adds verbosity to logging, making it more clear when GRPC service is invoked):

       "Microsoft.AspNetCore.Hosting": "Information",
       "Microsoft.AspNetCore.Routing.EndpointMiddleware": "Information"

4. Show greet.proto

   • Explain.
   • Show Properties.

5. Show GreeterService.cs

   • Show Generated class
   • Demonstrate updating

6. Run

   • Demonstrate trying to access in browser

Creating Client

1. Run Client Setup Script

2. Open sln

3. Copy Protos folder from Server

4. Open Greet.proto, change namespace

5. Add to .csproj (need to unload and reload)

   <ItemGroup>
       <Protobuf Include="Protos\greet.proto" GrpcServices="Client" />
   </ItemGroup>

6. Run, demonstrating communication with server.

7. Add Greet Client Program.cs

New Service

Create new Service On Server

1. Create order.proto
   • Talk about datetime. Include this link:
     • Protobuf scalar data types - gRPC for WCF developers | Microsoft Docs
2. Create a C# OrderService
   • Try to inherit from OrderProtoService.
   • It doesn't work, why not?
   • Need to change compile options.
3. Add to Program.cs

Update Client to Consume New Service

1. Copy order.proto from server to client.
2. Add to .csproj
3. Add order-client-program-v1.cs
4. Demonstrate

Using Streams

1. Add delay to order provider to simulate server latency.
2. Demonstrate how latency creates inefficicies with unary calls.
3. Update order.proto with order-v2.proto, which adds a streaming method.
4. Update order service with OrderService-v2.cs.
5. Update client with order-client-program-v2.cs.
6. Re-run server and client.
7. Demonstrate how streaming method is more performant.

Client Side Load Balancing / Transient Fault Handling

1. Update client with order-client-program-v3

2. Explain DNS service discovery

   • Can use DNS service (SRV) records.

3. Start multiple instances of server, demonstrating load balancing / failover:

   dotnet run --no-build --urls="http://localhost:5126/" --project "S:\Projects\Grpc.Demo\Server\Grpc.Demo.Server\Grpc.Demo.Server.csproj"
   dotnet run --no-build --urls="http://localhost:5127/" --project "S:\Projects\Grpc.Demo\Server\Grpc.Demo.Server\Grpc.Demo.Server.csproj"
   dotnet run --no-build --urls="http://localhost:5128/" --project "S:\Projects\Grpc.Demo\Server\Grpc.Demo.Server\Grpc.Demo.Server.csproj"

4. Switch round robin config to PickFirstConfig.

.NET Framework Support

1. Requiress 4.6.1 or later
2. Requires Grpc.Core, a maintenance mode project
3. Doesn't support outbound streams

Authentication

Authentication and authorization in gRPC for ASP.NET Core | Microsoft Docs

• Supported:
  • Simplest -- bearer token
  • Certificate
  • JWT Tokens
  • OAuth
  • OpenId Connect
• Similar to securing a Web API app (authorization attributes, etc.)

Sample Projects

• GRPC Server (final version created in this demo)
• GRPC Client (final version created in this demo)
• GRPC Legacy (.NET Framework) Client

Links / Additional Reading

GRPC

• Create a .NET Core gRPC client and server in ASP.NET Core | Microsoft Docs
• Use gRPC client with .NET Standard 2.0 | Microsoft Docs
• Versioning gRPC services | Microsoft Docs
• Performance best practices with gRPC | Microsoft Docs

Proto

• protobuf-net/protobuf-net: Protocol Buffers library for idiomatic .NET (github.com)
• Language Guide  |  Protocol Buffers  |  Google Developers
• Protobuf scalar data types - gRPC for WCF developers | Microsoft Docs