Quarkus: Try to cache maven dependencies using multistage docker build - maven

Question

I have got a simple Quarkus application and I try to build it using the following multistage Dockerfile.
FROM maven:3-jdk-8-slim AS build
WORKDIR /build
# Download Dependencies
COPY pom.xml .
RUN mvn dependency:go-offline
# Build App
COPY src/ /build/src/
RUN mvn -Dmaven.test.skip=true package -Dcheckstyle.skip
# Stage 2 : create the docker final image
FROM adoptopenjdk:8-jre-openj9 AS runtime
COPY --from=build /build/target/*-runner.jar /app/app.jar
COPY --from=build /build/target/lib/* /app/lib/
WORKDIR /app
RUN chgrp -R 0 /app &&\
chmod g=u /app
USER 1001
EXPOSE 8080
ENTRYPOINT ["java", "-Djava.security.egd=file:/dev/./urandom", "-jar", "/app/app.jar"]
and the pom.xml
<?xml version="1.0"?>
<project
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<groupId>com.test</groupId>
<artifactId>booking-mgr</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<compiler-plugin.version>3.8.1</compiler-plugin.version>
<maven.compiler.parameters>true</maven.compiler.parameters>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<quarkus-plugin.version>1.1.1.Final</quarkus-plugin.version>
<quarkus.platform.artifact-id>quarkus-universe-bom</quarkus.platform.artifact-id>
<quarkus.platform.group-id>io.quarkus</quarkus.platform.group-id>
<quarkus.platform.version>1.1.1.Final</quarkus.platform.version>
<surefire-plugin.version>2.22.1</surefire-plugin.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>${quarkus.platform.group-id}</groupId>
<artifactId>${quarkus.platform.artifact-id}</artifactId>
<version>${quarkus.platform.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.10</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-resteasy</artifactId>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-junit5</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>rest-assured</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-resteasy-jsonb</artifactId>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-smallrye-openapi</artifactId>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-smallrye-reactive-messaging-kafka</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-maven-plugin</artifactId>
<version>${quarkus-plugin.version}</version>
<executions>
<execution>
<goals>
<goal>build</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>${compiler-plugin.version}</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>${surefire-plugin.version}</version>
<configuration>
<systemProperties>
<java.util.logging.manager>org.jboss.logmanager.LogManager</java.util.logging.manager>
</systemProperties>
</configuration>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>native</id>
<activation>
<property>
<name>native</name>
</property>
</activation>
<build>
<plugins>
<plugin>
<artifactId>maven-failsafe-plugin</artifactId>
<version>${surefire-plugin.version}</version>
<executions>
<execution>
<goals>
<goal>integration-test</goal>
<goal>verify</goal>
</goals>
<configuration>
<systemProperties>
<native.image.path>
${project.build.directory}/${project.build.finalName}-runner
</native.image.path>
</systemProperties>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<properties>
<quarkus.package.type>native</quarkus.package.type>
</properties>
</profile>
</profiles>
</project>
The build works fine, it downloads the maven dependencies, then it creates the .jar and runs the .jar in the final container. But if I change something in the source code and leave the pom.xml untouched, the dependencies are downloaded again. It seems that mvn dependency:go-offline does not download all dependencies.
Is there a way to speed up docker builds that way? For example, I do the same with Spring Boot and everything works great there.
Thank you for your help.

Answer 1

Your pom.xml and src folder are in the build context (the dot in your command).
If you change files in src then you change your build context so you invalidate the COPY cache.
See Docker build is not using cache

Answer 2

Simply, you can split the Dockerfile into two, such as builder-base.dockerfile and final.dockerfile. Then, create a directory builder-base and move pom.xml into builder-base.
directory structure:
.
+-- builder-base
| +-- pom.xml
|-- src
|-- builder-base.dockerfile
|-- final.dockerfile
In the final.dockerfile is :
FROM java-builder AS build
# Build App
COPY src/ /build/src/
RUN mvn -Dmaven.test.skip=true package -Dcheckstyle.skip
# Stage 2 : create the docker final image
FROM adoptopenjdk:8-jre-openj9 AS runtime
COPY --from=build /build/target/*-runner.jar /app/app.jar
COPY --from=build /build/target/lib/* /app/lib/
WORKDIR /app
RUN chgrp -R 0 /app &&\
chmod g=u /app
USER 1001
EXPOSE 8080
ENTRYPOINT ["java", "-Djava.security.egd=file:/dev/./urandom", "-jar", "/app/app.jar"]
First, put this code into builder-base.dockerfile:
FROM maven:3-jdk-8-slim
WORKDIR /build
# Download Dependencies
COPY pom.xml .
RUN mvn dependency:go-offline
So, at first, you should build a image named 'java-builder'
docker build -t java-builder -f builder.dockerfile ./builder-base
Now, you can compile the source code use the command below:
docker build -t app -f final.dockerfile .
The base image in the final.dockerfile is java-builder, if you don't re-build the image, you can always create the docker final image using the cache.

Answer 3

I found mvn package will do the work.
Now I use:
COPY pom.xml .
RUN mvn --batch-mode \
--quiet \
--errors \
dependency:go-offline \
package
COPY src ./src
RUN mvn --batch-mode \
--quiet \
--errors \
--define maven.test.skip=true \
--define java.awt.headless=ture \
clean package
Looks weird, but no errors.