spring-webflux-reactive-databases

The goal of this project is to play with Spring WebFlux both on client and server side. For it, we will implement Spring Boot Java Web applications (product-api, customer-api, order-api, notification-api and client-shell) and use different databases like Cassandra, MongoDB, Postgres and MySQL.

Proof-of-Concepts & Articles

On ivangfr.github.io, I have compiled my Proof-of-Concepts (PoCs) and articles. You can easily search for the technology you are interested in by using the filter. Who knows, perhaps I have already implemented a PoC or written an article about what you are looking for.

Project Architecture

Applications

product-api

Spring Boot Java Web application that exposes a REST API to manage products. It uses MongoDB as storage.
customer-api

Spring Boot Java Web application that exposes a REST API to manage customers. It uses Postgres as storage.
order-api

Spring Boot Web Java application that exposes a REST API to manage orders. It uses Cassandra as storage. In order to get more information about an order, i.e, the name of the customer who placed it or the name or price of the products in the order, order-api uses WebClient and CompletableFuture to fetch this information from customer-api and product-api.
notification-api

Spring Boot Web Java application that exposes a REST API to manage notifications.
client-shell

Spring Boot Shell Java application that has a couple of commands to interact with product-api, customer-api, order-api and notification-api. The picture below show those commands.

Prerequisites

Initialize Environment

Open a terminal and inside spring-webflux-reactive-databases root folder run
```
./init-environment.sh
```
Wait for the script to finish

Run applications with Maven

product-api

Open a new terminal and, inside spring-webflux-reactive-databases root folder, run the following command
```
./mvnw clean spring-boot:run --projects product-api
```
customer-api

Open a new terminal and, inside spring-webflux-reactive-databases root folder, run the following command
```
./mvnw clean spring-boot:run --projects customer-api
```
order-api

Open a new terminal and, inside spring-webflux-reactive-databases root folder, run the following command
```
./mvnw clean spring-boot:run --projects order-api
```
notification-api

Open a new terminal and, inside spring-webflux-reactive-databases root folder, run the following command
```
./mvnw clean spring-boot:run --projects notification-api
```
client-shell

Open a new terminal and, inside spring-webflux-reactive-databases root folder, run the following command to build the executable jar file
```
./mvnw clean package --projects client-shell -DskipTests
```
To start client-shell run
```
./client-shell/target/client-shell-1.0.0.jar
```

Run applications as Docker containers

Build Docker Images
- In a terminal, make sure you are in spring-webflux-reactive-databases root folder
- Run the following script to build the Docker images
  - JVM
```
./docker-build.sh
```
  - Native (it's not implemented yet)
```
./docker-build.sh native
```

Environment Variables

product-api

Environment Variable Description

MONGODB_HOST Specify host of the Mongo database to use (default localhost)

MONGODB_PORT Specify port of the Mongo database to use (default 27017)
customer-api

Environment Variable Description

POSTGRES_HOST Specify host of the Postgres database to use (default localhost)

POSTGRES_PORT Specify port of the Postgres database to use (default 5432)

Environment Variable	Description
`MONGODB_HOST`	Specify host of the `Mongo` database to use (default `localhost`)
`MONGODB_PORT`	Specify port of the `Mongo` database to use (default `27017`)

Environment Variable	Description
`POSTGRES_HOST`	Specify host of the `Postgres` database to use (default `localhost`)
`POSTGRES_PORT`	Specify port of the `Postgres` database to use (default `5432`)

order-api

Environment Variable	Description
`CASSANDRA_HOST`	Specify host of the `Cassandra` database to use (default `localhost`)
`CASSANDRA_PORT`	Specify port of the `Cassandra` database to use (default `9042`)
`PRODUCT_API_HOST`	Specify host of the `product-api` to use (default `localhost`)
`PRODUCT_API_PORT`	Specify port of the `product-api` to use (default `9080`)
`CUSTOMER_API_HOST`	Specify host of the `customer-api` to use (default `localhost`)
`CUSTOMER_API_PORT`	Specify port of the `customer-api` to use (default `9081`)

notification-api

Environment Variable	Description
`MYSQL_HOST`	Specify host of the `MySQL` database to use (default `localhost`)
`MYSQL_PORT`	Specify port of the `MySQL` database to use (default `3306`)
`CUSTOMER_API_HOST`	Specify host of the `customer-api` to use (default `localhost`)
`CUSTOMER_API_PORT`	Specify port of the `customer-api` to use (default `9081`)
`ORDER_API_HOST`	Specify host of the `order-api` to use (default `localhost`)
`ORDER_API_PORT`	Specify port of the `order-api` to use (default `9082`)

client-shell

Environment Variable	Description
`PRODUCT_API_HOST`	Specify host of the `product-api` to use (default `localhost`)
`PRODUCT_API_PORT`	Specify port of the `product-api` to use (default `9080`)
`CUSTOMER_API_HOST`	Specify host of the `customer-api` to use (default `localhost`)
`CUSTOMER_API_PORT`	Specify port of the `customer-api` to use (default `9081`)
`ORDER_API_HOST`	Specify host of the `order-api` to use (default `localhost`)
`ORDER_API_PORT`	Specify port of the `order-api` to use (default `9082`)
`NOTIFICATION_API_HOST`	Specify host of the `notification-api` to use (default `localhost`)
`NOTIFICATION_API_PORT`	Specify port of the `notification-api` to use (default `9083`)

Start Docker Containers
- In a terminal, make sure you are inside spring-webflux-reactive-databases root folder
- Run following command
```
./start-apis.sh && ./start-shell.sh
```

Application's URL

Application	URL
product-api	http://localhost:9080/swagger-ui.html
customer-api	http://localhost:9081/swagger-ui.html
order-api	http://localhost:9082/swagger-ui.html
notification-api	http://localhost:9083/swagger-ui.html

Playing around

Warning: the ids shown below will be different when you run it

In client-shell terminal, import some products and customers by running the following command
- If you are running using Maven
```
script ../src/main/resources/samples.txt
```
- If you are running as Docker container
```
script /app/resources/samples.txt
```

Get all customer

get-customers

It should return

{"id":"1","name":"Customer A","email":"customer.a@test.com","city":"Berlin","street":"NYC Strasse","number":"123"}
{"id":"2","name":"Customer B","email":"customer.b@test.com","city":"Berlin","street":"LA Strasse","number":"234"}
{"id":"3","name":"Customer C","email":"customer.c@test.com","city":"Berlin","street":"DC Strasse","number":"345"}
...

Get all products

get-products

It should return

{"id":"5ee3ee31b460d868af49f389","name":"product-1","price":199.99}
{"id":"5ee3ee32b460d868af49f38a","name":"product-2","price":299.99}
...

Create an order where Customer A buys 1 unit of product-1 and 2 units of product-2

create-order --customerId 1 --products 5ee3ee31b460d868af49f389:1;5ee3ee32b460d868af49f38a:2

It should return

{
  "orderId":"5aaad64c-4e80-48e0-926d-8f1b7027955a",
  "status":"OPEN",
  "created":"2020-06-12T22:09:59.558232",
  "products": [
    {"id":"5ee3ee31b460d868af49f389", "quantity":1},
    {"id":"5ee3ee32b460d868af49f38a", "quantity":2}
  ],
  "customerId":"1"
}

Get details about the order created

get-order-detailed 5aaad64c-4e80-48e0-926d-8f1b7027955a

It should return

{
  "orderId":"5aaad64c-4e80-48e0-926d-8f1b7027955a",
  "status":"OPEN",
  "created":"2020-06-12T22:09:59.558",
  "products": [
    {"id":"5ee3ee32b460d868af49f38a", "name":"product-2", "quantity":2, "price":299.99},
    {"id":"5ee3ee31b460d868af49f389", "name":"product-1", "quantity":1, "price":199.99}
  ],
  "customer": {
    "id":"1",
    "name":"Customer A",
    "email":"customer.a@test.com",
    "city":"Berlin",
    "street":"NYC Strasse",
    "number":"123"
  }
}

To create a notification to the order created above

create-notification 5aaad64c-4e80-48e0-926d-8f1b7027955a

To check how fast order-api get details about the customer and products of an order, create another order where Customer A order 50 random products

create-order-random --customerId 1 --numProducts 50

It should return

{
  "orderId":"87133d36-67f0-4388-b15b-7d66ad739374",
  "status":"OPEN",
  "created":"2020-06-12T22:14:08.342338",
  "products": [
    {"id":"5ee3ee32b460d868af49f38a", "quantity":4},
    ...
    {"id":"5ee3ee32b460d868af49f396", "quantity":3}
  ],
  "customerId":"1"
}

In another terminal, to get the details of the order previously created and the response time of this call, we are using order-api's endpoint GET /api/orders/{orderId}/detailed

curl -w "\n\nResponse Time: %{time_total}s" -s localhost:9082/api/orders/87133d36-67f0-4388-b15b-7d66ad739374/detailed

It will return something like

{
  "orderId":"87133d36-67f0-4388-b15b-7d66ad739374",
  "status":"OPEN",
  "created":"2020-06-12T22:14:08.342338",
  "products": [
    {"id":"5ee3ee32b460d868af49f395", "name":"product-13", "quantity":4, "price":1399.99},
    ...
  ],
  "customer": {
    "id":"1",
    "name":"Customer A",
    "email":"customer.a@test.com",
    "city":"Berlin",
    "street":"NYC Strasse",
    "number":"123"
  }
}

Response Time: 0.292698s

Useful Commands

Cassandra

docker exec -it cassandra cqlsh
USE mycompany;
SELECT * FROM orders;

Type exit to get out of cqlsh

MongoDB

docker exec -it mongodb mongosh productdb
db.products.find()

Type exit to get out of MongoDB shell

Postgres

docker exec -it postgres psql -U postgres -d customerdb
\dt customer
SELECT * FROM CUSTOMER;

Type exit to get out of psql

MySQL

docker exec -it -e MYSQL_PWD=secret mysql mysql -uroot --database notificationdb
SELECT * FROM notification;

Type exit to get out of MySQL monitor

Shutdown

To stop client-shell, go to the terminal where it is running and type exit
To stop product-api, customer-api and order-api
- If you start them with Maven, go to the terminals were they are running and press Ctrl+C
- If you start them as Docker containers, go to a terminal and, inside spring-webflux-reactive-databases root folder, run the following script
```
./stop-apis.sh
```
To stop and remove the database containers, network and volumes, go to a terminal and, inside spring-webflux-reactive-databases root folder, run the script below
```
./shutdown-environment.sh
```

Cleanup

To remove all Docker images created by this project, go to a terminal and, inside spring-webflux-reactive-databases root folder, run the following script

./remove-docker-images.sh

References

https://projectreactor.io/docs/core/release/reference/

angelmartz/spring-webflux-reactive-databases

spring-webflux-reactive-databases

Proof-of-Concepts & Articles

Project Architecture

Applications

product-api

customer-api

order-api

notification-api

client-shell

Prerequisites

Initialize Environment

Run applications with Maven

Run applications as Docker containers

Build Docker Images

Environment Variables

Start Docker Containers

Application's URL

Playing around

Useful Commands

Shutdown

Cleanup

References