ticketr.io

A cloud-native, microservice-based application for booking plane tickets. It demonstrates how several microservices can be wired together using both async and sync means to form a cohesive application. It is not a business-ready product, since some aspects depend on the specific business-case implementation and the airline billing policies. All microservices are placed in the same git repo just for GitHub tidiness. In a real business scenario, ideally each one will be in a separate git repository.

The following microservices are in place:

• api-gateway - REST API entry point. It routes requests to the responsible microservice and utilizes circuit breaker functionality
• service-registry - Registers and coordinates the sync communication.
• ticket-booking-service - The entry point. Provides REST API for booking new tickets. Stores them in MongoDb
• ticket-pricing-service - Calculates the price of the plane ticket depending on numerous factors. Invoked synchronously via REST.
• invoicing-service - Listens for events for newly booked tickets on the Kafka topic, generates pdf invoice documents and sends them by email to the recipient.

How to run the project locally

Option 1: using Docker compose

Prerequisites: Docker

• From repository's root execute:

  docker-compose up -d

Option 2: using Kubernetes

Prerequisites: Kubernetes

• From repository's root execute:

  kubectl apply -f k8s-scripts/main

• Expose the port of the API gateway

  kubectl port-forward service/api-gateway 8080:8080

• (Optional) to enable consolidated logging based on Elastic Stack, execute:

  kubectl apply -f k8s-scripts/elasticStack

  kubectl port-forward service/kibana 5601:5601

  You can now access Kibana at: http://localhost:5601/ Create a new index pattern: filebeat* and explore the logs from all microservices utilizing ElasticSearch's powerful search engine

Optional configurations

The following environment variables can be set for each service to override the default settings. Default values are meant to be used only for testing on a local dev environment.

api-gateway

• EUREKA_URI - full URL of the Eureka service registry. default: http://localhost:8761/eureka

ticket-booking-service

• MONGO_URI - a connection string URI for MongoDB. default: mongodb://root:rootpassword@localhost:27017/ticket_bookings?authSource=admin
• EUREKA_URI - full URL of the Eureka service registry. default: http://localhost:8761/eureka
• KAFKA_URI - host and port of the running Kafka instance. default: localhost:29090

ticket-pricing-service

• EUREKA_URI - full URL of the Eureka service registry. default: http://localhost:8761/eureka

invoicing-service

• ENABLE_EMAIL_SENDING - if true, each issued invoice will be sent by email. Default: false
• SMTP_HOST - the host of the SMTP server. Default: smtp.mailtrap.io (good for testing)
• SMTP_PORT - the port of the SMTP server. Default: 25 (mailtrap's default port)
• SMTP_USERNAME - smtp server's username. Default: test
• SMTP_PASSWORD - smtp server's password. Default: test
• KAFKA_URI - host and port of the running Kafka instance. default: localhost:29090

Useful tips

• To explore the booking API, open the Swagger UI page of the booking service: http://localhost:8083/swagger-ui/index.html
  • In addition, the OpenAPI spec file can be viewed at: http://localhost:8083/v3/api-docs/
• After starting the service registry, Eureka's dashboard can be accessed at: http://localhost:8761/ . Each registered microservice will be visible there.
• For debugging purpose, a console consumer can be opened on the Kafka topic (ticket-booking-topic):
  • docker exec -it <kafka-container-id> bash
  • cd ../../bin
  • ./kafka-console-consumer --bootstrap-server localhost:9092 --topic ticket-booking-topic --from-beginning
• Example CURL to make a new plane ticket booking:

    curl --location --request POST 'http://localhost:8080/booking' \
      --header 'Content-Type: application/json' \
      --data-raw '{
      "userId": "user123",
      "originAirport": "SYD",
      "destinationAirport": "IST",
      "passengers": [
        {
          "passportNumber": "12345678",
          "firstName": "John",
          "lastName": "Doe",
          "billingPerson": true,
          "piecesOfCheckedBaggage": 1,
          "bookedSeats": [
            {
              "seatNumber": "25A",
              "seatClass": "ECONOMY",
              "flightNumber": "ML556"
            }
           ]
        }
      ],
      "flights": [
        {
         "flightNumber": "ML556",
         "scheduledTime": "2023-03-01 12:12:00",
         "flightOrigin": "SYD",
         "flightDestination": "KUL"
        },
        {
         "flightNumber": "TK099",
         "scheduledTime": "2023-03-02 10:00:00",
         "flightOrigin": "KUL",
         "flightDestination": "IST"
        }
      ]
      }