Microservices / REST / AxonServer

:octocat: /drestaurant-apps/drestaurant-monolith-rest-2 :octocat:

This is a thin layer which coordinates the application activity. It does not contain business logic. It does not hold the state of the business objects

We designed and structured our loosely coupled components in a modular way, and that enable us to choose different deployment strategy and take first step towards Microservices architectural style.

Each microservice:

has its own bounded context,
has shared event(sourcing) storage (AxonServer)
and we route and distribute messages (events, commands, queries) between them via AxonServer

This a second version (2.2) of the REST Microservices application in which we use AxonServer as an infrastructural component.

AxonServer & event messages & command messages & query messages

Both AxonFramework and AxonServer form an Axon platform.

The key characteristics of AxonServer are:

Dedicated infrastructure for exchanging three types of messages (commands, events, queries) in a message-driven micro-services environment
Purpose-built database system optimized for the storage of event data of the type that is generated by applications that use the event sourcing architecture pattern
Built-in knowledge on CQRS message patterns
Easy-to-use and easy-to-manage

AxonServer connector is configured by default (included in axon-spring-boot-starter) :

 <dependency>
     <groupId>org.axonframework</groupId>
     <artifactId>axon-spring-boot-starter</artifactId>
     <version>${axon.version}</version>
 </dependency>

Alternatively, you can exclude AxonServer connector and fallback to JPA event store and storage in general. In that case you have to choose (and configure, and operate) Spring Cloud to distribute commands, and Kafka or RabbitMQ to distribute events.

<dependency>
    <groupId>org.axonframework</groupId>
    <artifactId>axon-spring-boot-starter</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.axonframework</groupId>
            <artifactId>axon-server-connector</artifactId>
        </exclusion>
    </exclusions>
</dependency>

We did this already in the first version of ‘REST Microservices application’ as a proof that you can benefit from AxonFramework programming model only (without AxonServer as an infrastructural component). first version is using:

RabbitMQ to distribute events between microservices
Spring Cloud discovery and registry service (Eureka) to distribute commands between microservices
no out of the box option to distribute queries -> each microservice has command and query side component included -> there is no independent query microservice -> you can not scale good

AxonFramework programing model is recognizing three categories of messages at the moment:

commands
events
queries

and they require different mechanisms of routing and distributing. AxonServer is built with this in mind, and you should consider it as an important tactical asset in you architecture. This will enable you to focus on your domain model and strategic design.

AxonFramework and AxonServer are open source. Axon Server Enterprise is targeted towards mission-critical, medium to large scale production deployments of Axon.

Restaurant management

Read all restaurants

curl http://localhost:8085/restaurants

Create new restaurant

curl -i -X POST --header 'Content-Type: application/json' --header 'Accept: */*' -d '{
"menuItems": [
 {
   "id": "id1",
   "name": "name1",
   "price": 100
 }
],
"name": "Fancy"
}' 'http://localhost:8084/restaurants'

Mark restaurant order as prepared

curl -i -X PUT --header 'Content-Type: application/json' --header 'Accept: */*' 'http://localhost:8084/restaurants/RESTAURANT_ID/orders/RESTAURANT_ORDER_ID/markprepared'

Customer management

Read all customers

curl http://localhost:8085/customers

Create/Register new Customer

curl -i -X POST --header 'Content-Type: application/json' --header 'Accept: */*' -d '{
"firstName": "Ivan",
"lastName": "Dugalic",
"orderLimit": 1000
}' 'http://localhost:8082/customers'

Courier management

Read all couriers

curl http://localhost:8085/couriers

Create/Hire new Courier

curl -i -X POST --header 'Content-Type: application/json' --header 'Accept: */*' -d '{
"firstName": "John",
"lastName": "Doe",
"maxNumberOfActiveOrders": 20
}' 'http://localhost:8081/couriers'

Courier takes/claims the Order that is ready for delivery (prepared)

curl -i -X PUT --header 'Content-Type: application/json' --header 'Accept: */*' 'http://localhost:8081/couriers/COURIER_ID/orders/COURIER_ORDER_ID/assign'

Courier marks the order as delivered

curl -i -X PUT --header 'Content-Type: application/json' --header 'Accept: */*' 'http://localhost:8081/couriers/COURIER_ID/orders/COURIER_ORDER_ID/markdelivered'

Order management

Read all orders

 curl http://localhost:8085/orders

Create/Place the Order

curl -i -X POST --header 'Content-Type: application/json' --header 'Accept: */*' -d '{
"customerId": "CUSTOMER_ID",
"orderItems": [
 {
   "id": "id1",
   "name": "name1",
   "price": 100,
   "quantity": 0
 }
],
"restaurantId": "RESTAURANT_ID"
}' 'http://localhost:8083/orders'

Note: Replace CUSTOMER_ID and RESTAURANT_ID with concrete values.

Development

This project is driven using Maven.

Clone

$ git clone https://github.com/idugalic/digital-restaurant

Build

$ cd digital-restaurant
$ mvn clean install

Run microservices

NOTE: AxonServer is required.

$ cd digital-restaurant/drestaurant-apps/drestaurant-microservices-rest/drestaurant-microservices-rest-2-query
$ mvn spring-boot:run
$ cd digital-restaurant/drestaurant-apps/drestaurant-microservices-rest/drestaurant-microservices-rest-2-command-courier
$ mvn spring-boot:run
$ cd digital-restaurant/drestaurant-apps/drestaurant-microservices-rest/drestaurant-microservices-rest-2-command-customer
$ mvn spring-boot:run
$ cd digital-restaurant/drestaurant-apps/drestaurant-microservices-rest/drestaurant-microservices-rest-2-command-restaurant
$ mvn spring-boot:run
$ cd digital-restaurant/drestaurant-apps/drestaurant-microservices-rest/drestaurant-microservices-rest-2-command-order
$ mvn spring-boot:run

Infrastructure and Platform (As A Service)

AxonServer