GRPC JWT Auth Example

Quick example of JWT Auth in GRPC. It oversimplifies a couple things. First, it stores the refresh token in the access token which would defeat the purpose of having a long lived and short lived token, and the hmac key, user, and a couple other things are hard coded. Also, when it refreshes the token, it doesn't write the new one to disk. However, this provided me with a quick experiment into using JWT in GRPC auth.

Prerequisites

Installing with go install requires your GOBIN to be on your path for execution of the command later. For go and protobuf, snap can work on Ubuntu and Windows via WSL2, but it's worth looking into the official websites and considering the options.

sudo snap install go --classic
sudo snap install protobuf --classic
go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
go install github.com/go-task/task/v3/cmd/task@v3.27.1

Add to your .bashrc

export PATH="$PATH:$(go env GOPATH)/bin"

Build

task build

Run

The token generator creates a new token or an expired one and writes it to standard out for viewing purposes as well as to disk to simulate it being a token that the client has already stored in the past via some sort of login process. It contains a refresh token that the server considers to be valid for creating a new token with a day till expiration.

task newtoken

task expiredtoken

Generate a cert:

task cert

Run server (blocking)

task serve

Run client and greet:

task greet

Regenerate

protoc --go_out=. --go_opt=paths=source_relative \
    --go-grpc_out=. --go-grpc_opt=paths=source_relative \
    pb/helloworld.proto

Troubleshooting

If using docker desktop and WSL2, you might have docker mounting a Windows directory which causes and error mentioning too many tail fields.

Stop Docker Desktop
Restart wsl (wsl --shutdown) from PowerShell
Run snap commands
Restart Docker Desktop

License

Most of this is new, but I started with some work in the GRPC examples after modifying https://grpc.io/docs/languages/go/quickstart/ so that it can handle JWT auth.

PaluMacil / grpc-jwt-auth-helloworld