jfcarr / grpc_taste_of_it

gRPC materials for Taste of IT 2022 talk

gRPC - Taste of IT

gRPC materials for Taste of IT 2022 talk

Requirements

• .NET SDK (I used version 6)
• Python 3 with the venv module installed.

Project Setup

Detailed instructions assume a Linux environment. There are helper scripts for Linux and Windows. Each step has a complete description of the changes to manually apply, and also instructions for running the helper script, if you want to save time.

First, reset everything with helper script:

Operating System	Helper Script
Linux	./helper.sh 999
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 999

.NET gRPC Service

Step 1.01 - Create Server Project

Create root folder for the projects:

mkdir src

cd src

Create service:

dotnet new grpc -o GrpcGreeterService

Update the applicationUrl in launchsettings.json to this:

"applicationUrl": "http://localhost:6000;https://localhost:6001"

(You can use whatever ports you need in your own projects. We're using these for consistency in the examples.)

Build the service:

cd GrpcGreeterService

dotnet build

Operating System	Helper Script
Linux	./helper.sh 101
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 101

Step 1.02 - New Messages in Protobuf

Update Protos/greet.proto, extending it with a couple of new messages:

message GoodbyeRequest { string name = 1; }

message GoodbyeReply { string message = 1; }

Build again:

dotnet build

Operating System	Helper Script
Linux	./helper.sh 102
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 102

Step 1.03 - New Method in Protobuf

Add a new method using the new messages:

service Greeter {
  // Sends a Hello greeting
  rpc SayHello(HelloRequest) returns (HelloReply);

  // Sends a Goodbye greeting
  rpc SayGoodbye(GoodbyeRequest) returns (GoodbyeReply);
}

Build again:

dotnet build

Operating System	Helper Script
Linux	./helper.sh 103
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 103

Step 1.04 - Implement the New Method

Open GreeterService.cs and add a new method using the new messages:

public override Task<GoodbyeReply> SayGoodbye(GoodbyeRequest request, ServerCallContext context)
{
	return Task.FromResult(new GoodbyeReply
	{
		Message = "Goodbye " + request.Name
	});
}

Build again:

dotnet build

Operating System	Helper Script
Linux	./helper.sh 104
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 104

Manual Step - Run the Server

Run the server:

Operating System	Server Script
Linux	./run_server.sh
Windows	powershell -ExecutionPolicy ByPass -file run_server.ps1

.NET gRPC Client

Step 2.01 - Create .NET Client Project

Change to the project root (src):

cd ..

Create the client project:

dotnet new console -o GrpcGreeterClient

Operating System	Helper Script
Linux	./helper.sh 201
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 201

Step 2.02 - Add Dependencies

Switch to the folder and add dependencies:

cd GrpcGreeterClient

dotnet add package Grpc.Net.Client
dotnet add package Google.Protobuf
dotnet add package Grpc.Tools

Operating System	Helper Script
Linux	./helper.sh 202
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 202

Step 2.03 - Copy and Update the Protobuf File

Create a Protos folder, then copy the .proto file from the service project:

mkdir Protos

cp ../GrpcGreeterService/Protos/greet.proto Protos/

Update the namespace inside the greet.proto file to the project's namespace:

option csharp_namespace = "GrpcGreeterClient";

Operating System	Helper Script
Linux	./helper.sh 203
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 203

Step 2.04 - Add Protobuf Entry to Project File

Edit the GrpcGreeterClient.csproj project file and add an item group with a <Protobuf> element that refers to the greet.proto file:

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

Build the client to generate the types:

dotnet build

Operating System	Helper Script
Linux	./helper.sh 204
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 204

Step 2.05 - Update Program.cs

Replace the contents of Program.cs with this:

using System.Threading.Tasks;
using Grpc.Net.Client;
using GrpcGreeterClient;

// The port number must match the port of the gRPC server.
using var channel = GrpcChannel.ForAddress("http://localhost:6000");

var client = new Greeter.GreeterClient(channel);

var helloReply = await client.SayHelloAsync(new HelloRequest { Name = "GreeterClient" });
Console.WriteLine("Greeting: " + helloReply.Message);

var goodbyeReply = await client.SayGoodbyeAsync(new GoodbyeRequest { Name = "GreeterClient" });
Console.WriteLine("Greeting: " + goodbyeReply.Message);

Operating System	Helper Script
Linux	./helper.sh 205
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 205

Manual Step - Run the .NET Client

Run the client:

Operating System	Server Script
Linux	./run_dotnet_client.sh
Windows	powershell -ExecutionPolicy ByPass -file run_dotnet_client.ps1

You should see this:

Greeting: Hello GreeterClient
Press any key to exit...

Python gRPC Client

Step 3.01 - Create Virtual Python Environment

Create a virtual Python environment:

cd src

python3 -m venv grpc_env

cd grpc_env

source bin/activate

Operating System	Helper Script
Linux	./helper.sh 301
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 301

Step 3.02 - Add Dependencies

Create requirements.txt file:

echo 'grpcio-tools ~= 1.30' > requirements.txt

Install the dependencies:

pip install -r requirements.txt

Operating System	Helper Script
Linux	./helper.sh 302
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 302

Step 3.03 - Create Project Folders

Create project folders:

mkdir grpc_client

cd grpc_client

mkdir protobufs

mkdir src

Operating System	Helper Script
Linux	./helper.sh 303
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 303

Step 3.04 - Copy Protobuf File

Copy the protocol buffer file from the server project:

cp ../../GrpcGreeterService/Protos/greet.proto protobufs/

Operating System	Helper Script
Linux	./helper.sh 304
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 304

Step 3.05 - Generate Python Code

Generate Python code:

cd src

python -m grpc_tools.protoc -I ../protobufs --python_out=. --grpc_python_out=. ../protobufs/greet.proto

This generates two files:

• greet_pb2_grpc.py
• greet_pb2.py

Operating System	Helper Script
Linux	./helper.sh 305
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 305

Step 3.06 - Create Client Script

Create a client.py file with the following contents:

import grpc

import greet_pb2_grpc
from greet_pb2 import HelloRequest, GoodbyeRequest

channel = grpc.insecure_channel("localhost:6000")

client = greet_pb2_grpc.GreeterStub(channel)

hello_request = HelloRequest (
	name = "GreeterClient"
)

goodbye_request = GoodbyeRequest (
	name = "GreeterClient"
)

hello_result = client.SayHello(hello_request)
goodbye_result = client.SayGoodbye(goodbye_request)

print(hello_result.message)
print(goodbye_result.message)

Operating System	Helper Script
Linux	./helper.sh 306
Windows	powershell -ExecutionPolicy ByPass -file helper.ps1 306

Manual Step - Run the Python Client

Run the Python client:

Operating System	Server Script
Linux	./run_python_client.sh
Windows	powershell -ExecutionPolicy ByPass -file run_python_client.ps1

Results:

Hello GreeterClient
Goodbye GreeterClient