Read Container Image Labels

ContainerImageLabelReader.java

package org.springframework.cloud.dataflow.registry;

import java.util.Map;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.commons.codec.binary.Base64;

import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;

/**
 * - Docker Image Labels:{configuration-properties.names=other.message, configuration-properties.classes=com.example.mylog.MyLogProperties}
 * - OCI Image Labels:{configuration-properties.names=other.message, configuration-properties.classes=com.example.mylog.MyLogProperties} 
 * - Spring Artifactory Docker Image Labels:{com.microsoft.product=Microsoft SQL Server, com.microsoft.version=14.0.3045.24, vendor=Microsoft}
 *
 * @author Christian Tzolov
 */
public class ContainerImageLabelReader {

	// https://github.com/opencontainers/image-spec/blob/master/media-types.md
	public static String OCI_IMAGE_MANIFEST_MEDIA_TYPE = "application/vnd.oci.image.manifest.v1+json";
	public static String DOCKER_IMAGE_MANIFEST_MEDIA_TYPE = "application/vnd.docker.distribution.manifest.v2+json";

	public static void main(String[] args) throws JsonProcessingException {

		String springArtifactoryUsername = args[0];
		// Get the encrypted pass from your https://repo.spring.io/webapp/#/profile Encrypted Password
		String springArtifactoryEncryptedPassword = args[1];

		System.out.println(">>>> Docker Image Labels:" + imageLabels(dockerHubAuthorizationHeaders("tzolov/my-log-sink"),
				"registry-1.docker.io",
				"tzolov/my-log-sink", "latest", DOCKER_IMAGE_MANIFEST_MEDIA_TYPE));

		System.out.println(">>>> OCI Image Labels:" + imageLabels(dockerHubAuthorizationHeaders("tzolov/my-log-sink-oci"),
				"registry-1.docker.io",
				"tzolov/my-log-sink-oci",
				"latest",
				OCI_IMAGE_MANIFEST_MEDIA_TYPE));

		System.out.println(">>>> Spring Artifactory Docker Image Labels:" + imageLabels(
				springArtifactoryAuthorizationHeaders(springArtifactoryUsername, springArtifactoryEncryptedPassword),
				"springsource-docker-private-local.jfrog.io",
				"mssql/database-prebuilt",
				"2017-CU12-ubuntu", DOCKER_IMAGE_MANIFEST_MEDIA_TYPE));
	}

	public static Map<String, String> imageLabels(HttpHeaders headers, String registryHost, String imageRepository,
			String imageTag, String manifestMediaType) throws JsonProcessingException {

		RestTemplate rest = new RestTemplate();

		headers.set(HttpHeaders.ACCEPT, manifestMediaType);
		final HttpEntity<String> entity = new HttpEntity<>(headers);

		// Docker Registry HTTP V2 API pull manifest
		ResponseEntity<Map> manifest = rest.exchange("https://{registryHost}/v2/{repository}/manifests/{tag}",
				HttpMethod.GET, entity, Map.class, registryHost, imageRepository, imageTag);
		String configDigest = ((Map<String, String>) manifest.getBody().get("config")).get("digest");

		// Docker Registry HTTP V2 API pull config blob
		ResponseEntity<String> configBlobOctet = rest.exchange("https://{registryHost}/v2/{repository}/blobs/{digest}",
				HttpMethod.GET, entity, String.class, registryHost, imageRepository, configDigest);

		// Extract labels from the config JSON response
		Map<String, Object> configBlob = new ObjectMapper().readValue(configBlobOctet.getBody(), Map.class);
		Map<String, String> labels = (Map<String, String>) ((Map<String, Object>) configBlob.get("config")).get("Labels");

		return labels;
	}

	public static HttpHeaders dockerHubAuthorizationHeaders(String imageRepository) {
		Map<String, String> access = new RestTemplate().getForObject("https://auth.docker.io/token?service=registry.docker.io&scope=repository:{repository}:pull&offline_token=1&client_id=shell", Map.class, imageRepository);
		String accessToken = access.get("token");
		final HttpHeaders headers = new HttpHeaders();
		headers.set(HttpHeaders.AUTHORIZATION, "Bearer " + accessToken);
		return headers;
	}

	public static HttpHeaders springArtifactoryAuthorizationHeaders(String user, String encryptedPassword) {
		final HttpHeaders headers = new HttpHeaders();
		headers.set(HttpHeaders.AUTHORIZATION, "Basic " + new String(Base64.encodeBase64((user + ":" + encryptedPassword).getBytes())));
		return headers;
	}
}