Is it possible to execute custom commands with the Docker Java API?

Question

Can the Docker Java client library (https://github.com/docker-java/docker-java) be used to execute custom commands?

I want to use the library to check if Docker images I need to download are compatible with multiple architectures (specifically, linux/arm/v6 and linux/amd64). If the images meet this criteria, I would like to pull them and then push them to a different registry, renaming them based on their architecture one by one.

For example: I pull the alpine:latest image which supports both linux/arm/v6 and linux/amd64 architectures, then I rename it to alpine-amd64:latest, alpine-armv6:latest, then I push this to my private registry.

I feel like I'm constrained by Docker Java client.

public void pullAndPushDockerImage(DockerImageRestRequest request, String appId) {
    String imageName = "alpine";
    String imageTag = "latest";
    List<String> platforms = List.of("linux/amd64", "linux/arm/v6");

    try (DockerClient client = createDockerClient(request, dockerHost)) {
        authConfig = Optional.ofNullable(new AuthConfig()
            .withUsername(request.getUserName())
            .withIdentityToken(request.getAccessToken())
            .withRegistryAddress(request.getExternalRegistryUrl()));

        for (String platform : platforms) {
            client.pullImageCmd(imageName + ":" + imageTag)
                .withPlatform(platform)
                .exec(new PullImageResultCallback() {
                    @Override
                    public void onNext(PullResponseItem item) {
                        // Verify image pull status
                        String status = item.getStatus();
                        System.out.println(status);
                    }
                }).awaitCompletion();
        }

        ...
        // pushing the images later on
    }
}

Logs:

Pulling from library/alpine
Digest: sha256:02bb6f428431fbc2809c5d1b41eab5a68350194fb508869a33cb1af4444c9b11
Status: Downloaded newer image for alpine:latest
Pulling from library/alpine
Digest: sha256:02bb6f428431fbc2809c5d1b41eab5a68350194fb508869a33cb1af4444c9b11
Status: Downloaded newer image for alpine:latest

pom.xml dependencies:

<!-- Docker Client for Java -->

  <dependency>
       <groupId>com.github.docker-java</groupId>
       <artifactId>docker-java</artifactId>
       <version>3.2.13</version>
  </dependency>

  <dependency>
       <groupId>com.github.docker-java</groupId>
       <artifactId>docker-java-transport-httpclient5</artifactId>
       <version>3.2.13</version>
  </dependency>

I tried the built-in pullImageCmd with the withPlatform parameter

Answer 1

If you have to do this with your docker command line you will first save the image with an other name then push it to your repository. So i suggest you to use a save command to create the new image name then reuse the image result as your parameter to push the image.