Demo Kit

This project is a simple demonstration of microservices using Springboot integrated with Zipkin. It is a simple project that lists quotes from Marvel movies and users can vote which one of them they like.

The application then tally the votes.

Prerequisites:

1. Kubernetes cluster (ex. microk8s )
2. Docker
3. Skaffold
4. Helm
5. Maven
6. jib-maven-plugin

Project structure

Main components are:

• frontend/ - Hosts the web pages as well as RESTful access to backend services.

• quotes/ - This component retrieves the Marvel character quotes data stored PostgresSQL.

• votes/ - This component keeps track of the votes on each quote.

• bot/ - The bot will randomly vote quotes to simmulate traffic into the kit.

• bot-go/ - Golang version of bot.

• protos/ - Keeps all proto files in one location.

• db/ - Contains all infrastructure related components such as PostgreSQL, Redis and flyway (to perform schema migrate).

  • db/postgres - Postgres kubernetes manifests.
  • db/redis - Redis kubernetes manifests.
  • db/schema-migrate/ - Flyway schema migration manifests. Run as Kubernetes Job.

• zipkin/ - Stashes all Zipkin kubernetes manifests.

Frontend

This is a springboot application that has a simple GUI, which calls the quote service to retrieve all the quotes, calls vote service to cast and tally votes. The frontend exposed these REST endpoints.

• /api/quote/list
• /api/vote/castVote
• /api/vote/tally

UI style is brought to you by Material Kit

Build

Go to the directory frontend/

To build the project, do a mvn clean install jib:dockerBuild For simplicity, you can also use the provided skaffold.yaml and run skaffold run -p local or skaffold dev -p local if you want continuous build and deploy to you local cluster.

Test

You can use Postman to test the frontend's RESTFul endpoints.

Quote

This is another springboot application that retrieves quotes stored in PostgreSQL. It uses gRPC java for communication.

Stacks:

• Springboot - 2.1.5.RELEASE
• Lognet grpc-springboot-starter

Build

Go to directory quotes

To build the project, do a mvn clean install jib:dockerBuild

Run

In order to run the quotes service, you need to have the Quotes DB up and running.

Use skaffold:

1. Start the quotes DB (postgres)

skaffold run -p quotes-db-local

2. Start the quotes service

skaffold run -p local

Checkout the skaffold.yaml.

Test

You can use grpcurl to test it from command line.

Using grpcurl

To get all quotes

grpcurl -plaintext localhost:50052 org.bal.vote.proto.internal.QuoteManagement/AllQuotes

To get quote by Id:

grpcurl -plaintext -d '{"quoteId":"0"}' localhost:50052 org.bal.vote.proto.internal.QuoteManagement/GetQuoteById

Vote

This is another springboot application that allows users to cast their favorite Marvel quotes. It also tallies all the votes.

It uses gRPC java for communication.

It stores its data in Redis.

Stacks:

• Springboot - 2.1.5.RELEASE
• Lognet grpc-springboot-starter
• Redis

Build

To build the project, do a mvn clean install jib:dockerBuild For simplicity, you can also use the provided skaffold.yaml and run skaffold run -p local or skaffold dev -p local if you want continuous build and deploy to you local cluster.

Run

In order to run the votes service, you need to have the Quotes DB up and running.

Use skaffold:

1. Start the Votes DB (Redis)

skaffold run -p votes-db-local

2. Start the vote service

skaffold run -p local

Checkout the skaffold.yaml.

Test

You can use grpcurl to test it from command line.

Using grpcurl

To get the votes tally

grpcurl -plaintext localhost:50052 org.bal.vote.proto.internal.VoteManagement/GetAllVotes

To cast a vote:

grpcurl -plaintext -d '{"quoteId":"0"}' localhost:50052 org.bal.vote.proto.internal.VoteManagement/CastVote

Enabling Grafana Loki and Promtail

helm upgrade --install loki loki/loki --namespace monitoring

helm upgrade --install promtail loki/promtail --set "loki.serviceName=loki --namespace monitoring"

Zipkin

To start Zipkin

skaffold run -p local

To stop Zipkin

skaffold delete -p local

Checkout the skaffold.yaml.

bot-go

The build uses a Dockerfile. Hence, docker daemon setup is required.