gRPC Spring Boot Demo

Overview

Demo application for a Spring Boot service which exposes a gRPC endpoint. Built using Maven.

Installation

How to build

Make sure you have Java 17+ installed.

Compile and run unit tests:

./mvnw clean verify

Run integration tests:

./mvnw clean verify -Dskip.unitTests=true -Pfunctional-tests

How to run

Run on Intellij

You can run the app (i.e. com.nkatirtzis.grpcdemo.Application) on Intellij.

Run as a Spring Boot application

./mvnw spring-boot:run

Run the jar file

To run the jar file:

java -jar service/target/service-0.0.1-SNAPSHOT-exec.jar

Run in minikube

To run the application as a Docker container in a minikube cluster:

make minikube-build
minikube kubectl -- apply -f charts/install.yaml

Properties

Property	Default value	Description
grpc.port	6565	Port where gRPC server is running
spring.zipkin.enabled	true	Enables Zipkin for traces
spring.zipkin.baseUrl	http://127.0.0.1:9411/	Host where trace data will be sent to. Need to be set if spring.zipkin.enabled is set to true.
spring.sleuth.sampler.probability	1	Configures the probability of spans exported. Value should be in range [0.0,1.0]

Usage

This app comes with server reflection enabled.

You can use a gRPC cmd tool such as grpc_cli or grpcurl to send requests to the app.

Health check

Check the server’s health status using grpc_cli:

grpc_cli call localhost:6565 Check ''

or using grpcurl:

grpcurl -plaintext -d '' localhost:6565 grpc.health.v1.Health/Check

Main endpoint

Hit the main endpoint using grpc_cli:

grpc_cli call localhost:6565 Reviews 'id:1'

or using grpcurl:

grpcurl -plaintext -d '{"id": 1}' localhost:6565 ReviewsService/GetReviews

Metrics

The app exposes an endpoint under /metrics where you can see a list of available metrics.

Traces

It has also been instrumented to report traces to Zipkin. To run Zipkin locally:

docker run -p 9411:9411 openzipkin/zipkin

Once you make gRPC request(s) to the app traces will be available on http://localhost:9411/zipkin/.