I'm having trouble building a Docker image for my Spring Boot application on my Mac. Here's the Dockerfile I'm using:
```dockerfile
FROM maven:3.9.9-eclipse-temurin-21-jammy AS builder
WORKDIR /app
COPY pom.xml .
RUN mvn dependency:go-offline -B
COPY src ./src
RUN mvn clean package
FROM openjdk:21-jdk AS runner
WORKDIR /app
COPY --from=builder ./app/target/patient-service-0.0.1-SNAPSHOT.jar ./app.jar
EXPOSE 4000
ENTRYPOINT ["java", "-jar", "app.jar"]
```
Could someone help me understand what might be going wrong?
4 Answers
Running `mvn package` inside the Dockerfile can be useful since it streamlines the process by pulling in dependencies automatically. But, you might prefer building locally and just copying the JAR or WAR file for a lighter image. That way, you won't have to rebuild every time you change your code.
You might run into issues if your Mac uses ARM architecture versus x64. It's worth checking if the images you’re using are compatible with your CPU type.
That's right! I had a similar problem, and it turned out to be related to the CPU architecture.
I got an error during the Docker build process:
```plaintext
Dockerfile:7
--------------------
5 | COPY pom.xml .
6 |
7 | >>> RUN mvn dependency:go-offline -B
8 |
9 | COPY src ./src
--------------------
ERROR: failed to solve: process "/bin/sh -c mvn dependency:go-offline -B" did not complete successfully: exit code: 134
```
What do you think the issue might be?
It seems like a tool issue. But check the Maven logs to see if they provide more context!
You could try changing the order of operations in your Dockerfile. Set your work directory to `/app` after copying your files there. I had a similar issue and rearranging commands helped.
Thanks for the tip! I made that change and realized it was also a compatibility issue with the Maven image and OpenJDK version.
Totally get that, but I think that way you also miss out on some caching optimizations you can get from building in Docker.