Pass port number from docker-maven-plugin to spring property - spring

Question

I'm developing Spring Data JPA project that targets a MySQL database, and I want to run end-to-end integration tests from Maven.
So far, I've configured io.fabric8.docker-maven-plugin to spin up a MySQL container during pre-integration-test phase. It will use a random available port, which I need to pass to my application.properties file.
I've tried Automatic property expansion using Maven but I suspect that the mysql.port maven property is only getting resolved after the spring properties are getting updated.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>example</groupId>
<artifactId>pass-port-number-from-docker-maven-plugin-to-spring-property</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- other jpa dependencies ... -->
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>integration-test</goal>
<goal>verify</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>docker-test</id>
<properties>
<docker-maven.version>0.21.0</docker-maven.version>
</properties>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<id>reserve-network-port</id>
<goals>
<goal>reserve-network-port</goal>
</goals>
<phase>process-resources</phase>
<configuration>
<portNames>
<portName>mysql.port</portName>
</portNames>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>${docker-maven.version}</version>
<configuration>
<images>
<image>
<alias>mysql</alias>
<name>mysql:5.7</name>
<run>
<env>
<MYSQL_ROOT_PASSWORD>my-secret-pw</MYSQL_ROOT_PASSWORD>
</env>
<ports>
<port>mysql.port:3306</port>
</ports>
<wait>
<log>ready for connections</log>
<!-- <time>20000</time> -->
</wait>
<log>
<prefix>mysql</prefix>
<date>ISO8601</date>
<color>blue</color>
</log>
</run>
</image>
</images>
</configuration>
<!-- Connect start/stop to pre- and
post-integration-test phase, respectively if you want to start
your docker containers during integration tests -->
<executions>
<execution>
<id>start</id>
<phase>pre-integration-test</phase>
<goals>
<goal>start</goal>
</goals>
</execution>
<execution>
<id>stop</id>
<phase>post-integration-test</phase>
<goals>
<goal>stop</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>
application.properties
mysql.port = #mysql.port#
When I run my test I get a connection error, and when I inspect target/classes/application.properties I see that #mysql.port# hasn't been updated.
Any suggestions would be much appreciated.

Answer 1

# only works if you extend from spring-boot-starter-parent; you didn't show the relevant portions of your pom.xml. Assuming you did that, try attaching reserve-network-port to process-sources phase, before process-resources. It's very possible that when Maven copies the resources, the reserve-network-port hasn't ran yet.
What happens if you hardcode 3306 in application.properties?