gRPC Calculator

A gRPC protobuf k8s calculator made in Go.

Usage

Server

go run cmd/server/main.go

NAME:
   main - Calculator Server

USAGE:
   main [global options] command [command options] [arguments...]

VERSION:
   0.0.1

COMMANDS:
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --bind-http value             bind address for HTTP (default: ":8080") [$BIND_HTTP]
   --bind-grpc value             bind address for gRPC (default: ":2338") [$BIND_GRPC]
   --bind-prometheus-http value  bind prometheus address for HTTP (default: ":8081") [$BIND_PROMETHEUS_HTTP]
   --jaeger-host value           Jaeger hostname (default: "127.0.0.1") [$JAEGER_HOST]
   --jaeger-port value           Jaeger port (default: 5775) [$JAEGER_PORT]
   --jaeger-sampler value        Jaeger sampler (default: 0.05) [$JAEGER_SAMPLER]
   --jaeger-tags value           Jaeger tags (default: "calculator") [$JAEGER_TAGS]
   --help, -h                    show help
   --version, -v                 print the version

This will provide 3 endpoints:

• gRPC at localhost:2338
• HTTP at http://localhost:8080
• Prometheus at http://localhost:8081

Client

Have the server run and then execute one of the following.

HTTP

curl -X POST -H "Content-Type: application/json" -d '{"expression":"3+5+(10*2)"}' "http://localhost:8080/compute"
{"result": "28"}

gRPC

via grpc_cli

To install grpc_cli on a Mac, run brew install grpc.

grpc_cli call localhost:2338 Compute 'expression: "3+5+(10*2)"'
connecting to localhost:2338
result: "28"

Rpc succeeded with OK status

via local client

go run cmd/client/main.go 3+5+(10*2)

Infra

Docker

Server docker image is auto-published via Github Actions at radutopala/grpc-calculator

Run locally

docker run -p8080:8080 -p2338:2338 radutopala/grpc-calculator:v0.0.1

Kubernetes

Minikube on Mac

Should have installed: minikube, kubectl

Run kubectl version and make sure you have the same major and minor versions for both client and server, else you'll get errors.

minikube start
kubectl apply -f infra/k8s/nginx-ingress-mandatory.yaml
minikube addons enable ingress
kubectl apply -f infra/k8s/ingress.yaml
kubectl apply -f infra/k8s/deployment.yaml
curl -kL -X POST -H "Content-Type: application/json" -d '{"expression":"3+5+(10*2)"}' http://192.168.99.100/compute
{"result":"28"}

where 192.168.99.100 is the external IP of Minikube.