Docker build using Spring Boot, Maven, and Cloud 9

Question

Hello,

I am trying to get up and running with Spring Boot, Maven, and AWS. I am following [this tutorial](https://aws.amazon.com/blogs/containers/build-and-deploy-a-spring-boot-application-to-aws-app-runner-with-a-ci-cd-pipeline-using-terraform/).

I had to install a different version of maven, as when I ran `sudo tar xf /tmp/apache-maven-*.tar.gz -C /opt` under **Install Apache Maven** the console said it wasn't able to unzip `apache-maven-3.8.1-bin.tar.gz`. I had to download a different version, `apache-maven-3.9.6-bin.tar.gz` and I was able to unzip this.

I also had to change `M2_HOME` to `M3_HOME` under **Set up Apache Maven**, and I had to `unset M2_HOME`. Then I was able to proceed.

In Cloud 9, the return of `mvn --version` is 
```
Apache Maven 3.2.5 (12a6b3acb947671f09b81f49094c53f426d8cea1; 2014-12-14T17:29:23+00:00)
Maven home: /usr/share/apache-maven
Java version: 17.0.9, vendor: Amazon.com Inc.
Java home: /usr/lib/jvm/java-17-amazon-corretto.x86_64
Default locale: en, platform encoding: UTF-8
OS name: "linux", version: "6.1.66-91.160.amzn2023.x86_64", arch: "amd64", family: "unix"
```

I am at the part **Build and tag the Petclinic docker image**. When I execute the command `docker build -t petclinic .` the console returns 
```
 => [internal] load build definition from Dockerfile 
...
 => ERROR [2/4] ADD target/spring-petclinic-2.3.0.jar app.jar                                                                                                                                                                                  0.0s
------
 > [2/4] ADD target/spring-petclinic-2.3.0.jar app.jar:
------
Dockerfile:3
--------------------
   1 |     FROM public.ecr.aws/bitnami/java:latest
   2 |     VOLUME /tmp
   3 | >>> ADD target/spring-petclinic-2.3.0.jar app.jar
   4 |     EXPOSE 80
   5 |     RUN apt-get update
--------------------
ERROR: failed to solve: failed to compute cache key: failed to calculate checksum of ref 3f20ae07-a774-435d-86a5-f05e04520cc5::ljcblcc6ijbrhcn5q5fi0vwyr: "/target/spring-petclinic-2.3.0.jar": not found
```
I am trying to fix the error caused by `ADD target/spring-petclinic-2.3.0.jar app.jar `.

My Dockerfile is 
```
FROM public.ecr.aws/bitnami/java:latest
VOLUME /tmp
ADD target/spring-petclinic-2.3.0.jar app.jar
EXPOSE 80
RUN apt-get update
RUN apt-get -y install awscli
ENTRYPOINT env spring.datasource.password=$(aws ssm get-parameter --name /database/password --with-decrypt --region $AWS_REGION | grep Value | cut -d '"' -f4) java -Djava.security.egd=file:/dev/./urandom -jar /app.jar
```
I found [this post](https://stackoverflow.com/questions/76602277/failed-to-calculate-checksum-of-ref) which talks about commands relative to your `Dockerfile`. I tried to update the command in my Dockerfile to

`ADD /home/ec2-user/environment/aws-apprunner-terraform/petclinic/target/spring-petclinic-2.3.0.jar app.jar`

but this returned a similar error to the one above. 
The return of `pwd` is

`/home/ec2-user/environment/aws-apprunner-terraform/petclinic`

and then the return of `ls` is

`Dockerfile  docker-compose.yml  pom.xml  readme.md  src`.

I noticed that `target` directory is not there. Should it?

Thank you for the help in getting started with Spring!

Saurabh_M · Accepted Answer

Hello,

From query I can clearly see that “/target/spring-petclinic-2.3.0.jar": not found .

As you already mentioned that target folder was not there and as per Dockerfile command “ADD target/spring-petclinic-2.3.0.jar app.jar” it will search for  spring-petclinic-2.3.0.jar  in "target" folder in current directory .

As per shared [document](https://aws.amazon.com/blogs/containers/build-and-deploy-a-spring-boot-application-to-aws-app-runner-with-a-ci-cd-pipeline-using-terraform/) The compiled java classes were placed in spring-petclinic/target/classes, which is another standard convention employed by Maven.

Hence I will suggest you to please verify and see why target folder is not getting generated . If you need further assistance we need to dig deeper into logs. And I will request you to please reach out to us by opening a support case with us.

I will be more than happy to assist with that.

Thank you!!!

Simone Tallevi · Answer

Hi Jeff,
before running the  ```Docker Build ``` command, did you run the **Package the application using Apache Maven**?

```
cd ~/environment/aws-apprunner-terraform/petclinic
mvn package -Dmaven.test.skip=true
```
This will create the target folder and the "spring-petclinic-2.3.0.jar" that you are missing into your Docker Build process

Docker build using Spring Boot, Maven, and Cloud 9

Relevant content