Monolith To Microservices

This is the source code for my article Maintaining Legacy Applications - Part Two.

Requirements

Java 11
Wildfly 20.0.1.Final
Docker 20.10.0
Docker Compose 1.25.0
MySQL 8.0.21
MySQL Java Connector 8.0.20
Keycloak 11.0.3
Quarkus 1.10.2.Final
Angular 10.0.6
Node.js 12.19.0
Yarn 1.22.5
Kafka
Debezium

Docker & Docker Compose

Install Docker and Docker Compose for your platform.

Starting a MySQL database.

Open a terminal in the directory where this source code was checked out and execute the commands:

cd docker/mysql
docker-compose up

Verify that the MySQL server starts. You should see output similar to the following:

2020-12-10T07:46:33.804006Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.22'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  MySQL Community Server - GPL.

Setup Wildfly

Download WildFly 20.0.1.Final from http://wildfly.org/downloads/

Download MySQL Connector jar from https://dev.mysql.com/downloads/connector/j/

Create directory structure in the WildFly exploded location of /modules/com/mysql/main

Copy mysql-connector-java-8.0.20.jar for MySQL Connector into this directory.

Create a file in the same directory called module.xml with the following content:

<?xml version='1.0' encoding='UTF-8'?>

<module xmlns="urn:jboss:module:1.1" name="com.mysql">

    <resources>
        <resource-root path="mysql-connector-java-8.0.20.jar"/>
    </resources>

    <dependencies>
        <module name="javax.api"/>
        <module name="javax.transaction.api"/>
    </dependencies>
</module>

...where the file name specified in path is the same as the file you copied into the directory.

Edit /standalone/configuration/standalone.xml within WildFly installation to have the following datasources subsystem config:

<subsystem xmlns="urn:jboss:domain:datasources:6.0">
    <datasources>
        <datasource jndi-name="java:jboss/datasources/ExampleDS" pool-name="ExampleDS" enabled="true" use-java-context="true" statistics-enabled="${wildfly.datasources.statistics-enabled:${wildfly.statistics-enabled:false}}">
            <connection-url>jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE</connection-url>
            <driver>h2</driver>
            <security>
                <user-name>sa</user-name>
                <password>sa</password>
            </security>
        </datasource>
        <datasource jta="true" jndi-name="java:/CayambeMonolith" pool-name="CayambeMonolith" enabled="true" use-ccm="true">
            <connection-url>jdbc:mysql://localhost:3306/cayambe_monolith</connection-url>
            <driver>mysql</driver>
            <security>
                <user-name>cayambe-monolith</user-name>
                <password>cayambe</password>
            </security>
        </datasource>
        <datasource jta="true" jndi-name="java:/CayambeHybrid" pool-name="CayambeHybrid" enabled="true" use-ccm="true">
            <connection-url>jdbc:mysql://localhost:3306/cayambe_hybrid</connection-url>
            <driver>mysql</driver>
            <security>
                <user-name>cayambe-hybrid</user-name>
                <password>cayambe</password>
            </security>
        </datasource>
        <drivers>
            <driver name="h2" module="com.h2database.h2">
                <xa-datasource-class>org.h2.jdbcx.JdbcDataSource</xa-datasource-class>
            </driver>
            <driver name="mysql" module="com.mysql">
                <driver-class>com.mysql.cj.jdbc.Driver</driver-class>
                <xa-datasource-class>com.mysql.cj.jdbc.MysqlXADataSource</xa-datasource-class>
            </driver>
        </drivers>
    </datasources>
</subsystem>

Setup Keycloak

Download the standalone server distribution from the Keycloak website and unzip it. Open a terminal and start the server with:

bin/standalone.sh -Djboss.socket.binding.port-offset=1010

Open an internet browser and navigate to http://localhost:9090/auth.

Follow the Getting Started instructions to setup the administrator account.

Import cayambe-realm.json

While in Keycloak click on Add realm then click the Select file button and find cayambe-realm.json in the keycloak directory then finally click the Create button.

jannie-louwrens / monolith-to-microservices