Adding a logging resolution listener

src/main/java/org/openrewrite/maven/MavenLoggingResolutionListener.java

@@ -0,0 +1,110 @@
+package org.openrewrite.maven;
+
+import org.apache.maven.plugin.logging.Log;
+import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.maven.tree.GroupArtifactVersion;
+import org.openrewrite.maven.tree.ManagedDependency;
+import org.openrewrite.maven.tree.MavenRepository;
+import org.openrewrite.maven.tree.Pom;
+import org.openrewrite.maven.tree.ResolutionEventListener;
+import org.openrewrite.maven.tree.ResolvedDependency;
+import org.openrewrite.maven.tree.ResolvedGroupArtifactVersion;
+import org.openrewrite.maven.tree.ResolvedPom;
+import org.openrewrite.maven.tree.Scope;
+
+import java.util.List;
+import java.util.Objects;
+
+public class MavenLoggingResolutionListener implements ResolutionEventListener {
+
+    private final Log logger;
+
+    public MavenLoggingResolutionListener(Log logger) {
+        this.logger = Objects.requireNonNull(logger, "logger cannot be null");
+    }
+
+    @Override
+    public void downloadMetadata(GroupArtifactVersion gav) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Downloading metadata for " + gav);
+        }
+    }
+
+    @Override
+    public void download(GroupArtifactVersion gav) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Downloading " + gav);
+        }
+    }
+
+    @Override
+    public void downloadSuccess(ResolvedGroupArtifactVersion gav, @Nullable ResolvedPom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Downloaded " + gav + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void downloadError(GroupArtifactVersion gav, List<String> attemptedUris, @Nullable Pom containing) {
+        if (logger.isInfoEnabled()) {
+            StringBuilder sb = new StringBuilder("Failed to download " + gav + pomContaining(containing));
+            attemptedUris.forEach(uri -> sb.append("\n  - ").append(uri));
+            logger.debug(sb);
+        }
+    }
+
+    @Override
+    public void parent(Pom parent, Pom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolved parent pom " + containing + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void dependency(Scope scope, ResolvedDependency resolvedDependency, ResolvedPom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolved dependency " + resolvedDependency + " with scope " + scope + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void bomImport(ResolvedGroupArtifactVersion gav, Pom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolved imported dependency " + gav + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void property(String key, String value, Pom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolved property \"" + key + "\" with value \"" + value + "\"" + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void dependencyManagement(ManagedDependency dependencyManagement, Pom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolved managed dependency " + dependencyManagement + " on " + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void repository(MavenRepository mavenRepository, @Nullable ResolvedPom containing) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Resolving maven repository " + mavenRepository + pomContaining(containing));
+        }
+    }
+
+    @Override
+    public void repositoryAccessFailed(String uri, Throwable e) {
+        logger.info("Failed to access maven repository " + uri, e);
+    }
+
+    private static String pomContaining(@Nullable Pom containing) {
+        return containing != null ? " on " + containing : "";
+    }
+
+    private static String pomContaining(@Nullable ResolvedPom containing) {
+        return containing != null ? " on " + containing : "";
+    }
+}

src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java

@@ -465,6 +465,7 @@ public Map<MavenProject, Xml.Document> parseMaven(List<MavenProject> mavenProjec
         MavenSettings settings = buildSettings();
         MavenExecutionContextView mavenExecutionContext = MavenExecutionContextView.view(ctx);
         mavenExecutionContext.setMavenSettings(settings);
+        mavenExecutionContext.setResolutionListener(new MavenLoggingResolutionListener(logger));
 
         if (pomCacheEnabled) {
             //The default pom cache is enabled as a two-layer cache L1 == in-memory and L2 == RocksDb