Resolve metadata for org.apache.maven.plugins

core-it-suite/src/test/resources/bootstrap/pom.xml

@@ -51,6 +51,7 @@ under the License.
         <version>2.1-SNAPSHOT</version>
         <executions>
           <execution>
+            <id>dependencies</id>
             <goals>
               <goal>download</goal>
             </goals>
@@ -59,6 +60,19 @@ under the License.
               <file>${file}</file>
             </configuration>
           </execution>
+          <execution>
+            <id>metadata</id>
+            <goals>
+              <goal>download</goal>
+            </goals>
+            <phase>process-resources</phase>
+            <inherited>false</inherited>
+            <configuration>
+              <groupsToResolve>
+                <group>org.apache.maven.plugins</group>
+              </groupsToResolve>
+            </configuration>
+          </execution>
         </executions>
       </plugin>
     </plugins>

core-it-support/maven-it-plugin-bootstrap/src/main/java/org/apache/maven/its/bootstrap/DownloadMojo.java

@@ -22,6 +22,7 @@
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -37,11 +38,17 @@
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.project.ProjectBuildingRequest;
+import org.eclipse.aether.DefaultRepositorySystemSession;
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
 import org.eclipse.aether.collection.CollectRequest;
+import org.eclipse.aether.metadata.DefaultMetadata;
+import org.eclipse.aether.metadata.Metadata;
 import org.eclipse.aether.repository.RemoteRepository;
+import org.eclipse.aether.repository.RepositoryPolicy;
 import org.eclipse.aether.resolution.DependencyRequest;
+import org.eclipse.aether.resolution.MetadataRequest;
+import org.eclipse.aether.resolution.MetadataResult;
 
 /**
  * Boostrap plugin to download all required dependencies (provided in file) or to collect lifecycle bound build plugin
@@ -68,6 +75,12 @@ public class DownloadMojo extends AbstractMojo {
     @Parameter
     private File file;
 
+    /**
+     * A list of groupIds to resolve metadata.
+     */
+    @Parameter
+    private List<String> groupsToResolve;
+
     @Component
     private RepositorySystem repositorySystem;
 
@@ -76,6 +89,16 @@ public class DownloadMojo extends AbstractMojo {
 
     @Override
     public void execute() throws MojoFailureException {
+
+        ProjectBuildingRequest projectBuildingRequest = session.getProjectBuildingRequest();
+        RepositorySystemSession repositorySystemSession = projectBuildingRequest.getRepositorySession();
+        List<RemoteRepository> repos = RepositoryUtils.toRepos(projectBuildingRequest.getRemoteRepositories());
+
+        if (groupsToResolve != null && !groupsToResolve.isEmpty()) {
+            resolveMetaData(groupsToResolve, repositorySystemSession, repos);
+            return;
+        }
+
         // this or that: either resolver file listed artifacts or collect lifecycle packaging plugins
         if (file != null && file.exists()) {
             System.out.println("Collecting artifacts from file: " + file);
@@ -101,10 +124,6 @@ public void execute() throws MojoFailureException {
             }
         }
 
-        ProjectBuildingRequest projectBuildingRequest = session.getProjectBuildingRequest();
-        RepositorySystemSession repositorySystemSession = projectBuildingRequest.getRepositorySession();
-        List<RemoteRepository> repos = RepositoryUtils.toRepos(projectBuildingRequest.getRemoteRepositories());
-
         for (Dependency dependency : dependencies) {
             try {
                 org.eclipse.aether.graph.Dependency root =
@@ -138,4 +157,34 @@ static Dependency toDependency(String artifact) throws MojoFailureException {
         }
         return coordinate;
     }
+
+    /**
+     * Resolve metadata for maven plugins needs for MavenITmng7353CliGoalInvocationTest.
+     */
+    private void resolveMetaData(
+            List<String> groupsToResolve,
+            RepositorySystemSession repositorySystemSession,
+            List<RemoteRepository> repos) {
+
+        getLog().info("Resolving metadata for groups: " + groupsToResolve);
+
+        List<MetadataRequest> requests = new ArrayList<>();
+
+        for (String groupId : groupsToResolve) {
+            Metadata metadata =
+                    new DefaultMetadata(groupId, "maven-metadata.xml", DefaultMetadata.Nature.RELEASE_OR_SNAPSHOT);
+            for (RemoteRepository repository : repos) {
+                requests.add(new MetadataRequest(metadata, repository, "plugin"));
+            }
+        }
+
+        DefaultRepositorySystemSession session = new DefaultRepositorySystemSession(repositorySystemSession);
+        session.setUpdatePolicy(RepositoryPolicy.UPDATE_POLICY_ALWAYS);
+
+        List<MetadataResult> metadataResults = repositorySystem.resolveMetadata(session, requests);
+        for (MetadataResult metadataResult : metadataResults) {
+            getLog().info("metadata result: " + metadataResult.toString() + " from repository: "
+                    + metadataResult.getRequest().getRepository());
+        }
+    }
 }