Enhance error reporting for TychoRepositoryTransport

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/DefaultTransportCacheConfig.java

@@ -26,6 +26,8 @@
 @Component(role = TransportCacheConfig.class)
 public class DefaultTransportCacheConfig implements TransportCacheConfig, Initializable {
 
+	private static final boolean DEBUG_REQUESTS = Boolean.getBoolean("tycho.p2.transport.debug");
+
 	private boolean offline;
 	private boolean update;
 	private boolean interactive;
@@ -86,4 +88,9 @@ public File getCacheLocation() {
 		return cacheLocation;
 	}
 
+	@Override
+	public boolean isDebug() {
+		return DEBUG_REQUESTS;
+	}
+
 }

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/SharedHttpCacheStorage.java

@@ -90,7 +90,7 @@ public CacheEntry getCacheEntry(URI uri, Logger logger) throws FileNotFoundExcep
 				throw new FileNotFoundException(normalized.toASCIIString());
 			}
 			if (code == HttpURLConnection.HTTP_MOVED_PERM) {
-				return getCacheEntry(cacheLine.getRedirect(normalized), logger);
+				return getCacheEntry(cacheLine.getRedirect(normalized, logger), logger);
 			}
 		}
 		return new CacheEntry() {
@@ -252,7 +252,10 @@ public synchronized File fetchFile(URI uri, HttpTransportFactory transportFactor
 				}
 				updateHeader(response, code);
 				if (isRedirected(code)) {
-					URI redirect = getRedirect(uri);
+					URI redirect = getRedirect(uri, logger);
+					if (cacheConfig.isDebug()) {
+						logger.info("Redirect (code = " + code + ") from " + uri + " to " + redirect);
+					}
 					if (code == HttpURLConnection.HTTP_MOVED_TEMP) {
 						// https://github.com/eclipse-tycho/tycho/issues/4459
 						// Don't save temporary redirects since they might change later, rendering the
@@ -311,7 +314,7 @@ public synchronized File getFile(URI uri, HttpTransportFactory transportFactory,
 					throw new FileNotFoundException(uri.toString());
 				}
 				if (isRedirected(code)) {
-					return SharedHttpCacheStorage.this.getCacheEntry(getRedirect(uri), logger)
+					return SharedHttpCacheStorage.this.getCacheEntry(getRedirect(uri, logger), logger)
 							.getCacheFile(transportFactory);
 				}
 				if (file.isFile()) {
@@ -430,12 +433,17 @@ public int getResponseCode() {
 			return Integer.parseInt(getHeader().getProperty(RESPONSE_CODE, "-1"));
 		}
 
-		public URI getRedirect(URI base) throws FileNotFoundException {
+		public URI getRedirect(URI base, Logger logger) throws FileNotFoundException {
 			String location = getHeader().getProperty("location");
 			if (location == null) {
 				throw new FileNotFoundException(base.toASCIIString());
 			}
-			return base.resolve(location);
+			URI uri = base.resolve(location);
+			if (cacheConfig.isDebug()) {
+				logger.info(
+						"location given by header = '" + location + "', with base =" + base + ", resolves = " + uri);
+			}
+			return uri;
 		}
 
 		public Properties getHeader() {

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/TransportCacheConfig.java

@@ -22,5 +22,7 @@ public interface TransportCacheConfig {
 
 	boolean isInteractive();
 
+	boolean isDebug();
+
 	File getCacheLocation();
 }

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/TychoRepositoryTransport.java

@@ -58,8 +58,6 @@ public class TychoRepositoryTransport extends org.eclipse.equinox.internal.p2.re
 
 	private static final int MAX_DOWNLOAD_THREADS = Integer.getInteger("tycho.p2.transport.max-download-threads", 4);
 
-	private static final boolean DEBUG_REQUESTS = Boolean.getBoolean("tycho.p2.transport.debug");
-
 	private static final Executor DOWNLOAD_EXECUTOR = Executors.newFixedThreadPool(MAX_DOWNLOAD_THREADS,
 			new ThreadFactory() {
 
@@ -125,13 +123,12 @@ public IStatus downloadArtifact(URI source, OutputStream target, IArtifactDescri
 			}
 			return reportStatus(downloadStatus, target);
 		} catch (AuthenticationFailedException e) {
-			return reportStatus(Status.error("authentication failed for " + source, e), target);
+			return reportStatus(statusWithCode("authentication failed for %s",
+					ProvisionException.REPOSITORY_FAILED_AUTHENTICATION, source, e), target);
 		} catch (IOException e) {
 			if (e instanceof HttpTimeoutException) {
-				return reportStatus(new Status(IStatus.ERROR,
-						TychoRepositoryTransport.class,
-						ProvisionException.REPOSITORY_FAILED_READ,
-						"download from " + source + " timed out", e), target);
+				return reportStatus(statusWithCode("download from %s timed out",
+						ProvisionException.REPOSITORY_FAILED_READ, source, e), target);
 			}
 			return reportStatus(Status.error("download from " + source + " failed", e), target);
 		} catch (CoreException e) {
@@ -142,8 +139,9 @@ public IStatus downloadArtifact(URI source, OutputStream target, IArtifactDescri
 	@Override
 	public InputStream stream(URI toDownload, IProgressMonitor monitor)
 			throws FileNotFoundException, CoreException, AuthenticationFailedException {
-		if (DEBUG_REQUESTS) {
-			logger.debug("Request stream for " + toDownload);
+		boolean debug = cacheConfig.isDebug();
+		if (debug) {
+			logger.info("Request stream for " + toDownload);
 		}
 		requests.increment();
 		if (toDownload.toASCIIString().endsWith("p2.index")) {
@@ -154,28 +152,35 @@ public InputStream stream(URI toDownload, IProgressMonitor monitor)
 			if (handler != null) {
 				File cachedFile = handler.getFile(toDownload);
 				if (cachedFile != null) {
-					if (DEBUG_REQUESTS) {
+					if (debug) {
 						logger.debug(" --> routed through handler " + handler.getClass().getSimpleName());
 					}
 					return new FileInputStream(cachedFile);
 				}
 			}
 			return toDownload.toURL().openStream();
 		} catch (FileNotFoundException e) {
-			if (DEBUG_REQUESTS) {
-				logger.debug(" --> not found!");
+			if (debug) {
+				logger.info(" --> not found! (" + toDownload + ")");
 			}
 			throw e;
+		} catch (java.net.http.HttpTimeoutException timeout) {
+			if (debug) {
+				logger.info(" --> timeout while requesting (" + toDownload + "): " + timeout);
+			}
+			throw new CoreException(statusWithCode("download from %s timed out",
+					ProvisionException.REPOSITORY_FAILED_READ, toDownload, timeout));
 		} catch (IOException e) {
 			if (e instanceof AuthenticationFailedException afe) {
 				throw afe;
 			}
-			if (DEBUG_REQUESTS) {
-				logger.debug(" --> generic error: " + e);
+			if (debug) {
+				logger.info(" --> generic error (" + toDownload + "): " + e);
 			}
-			throw new CoreException(Status.error("download from " + toDownload + " failed", e));
+			throw new CoreException(statusWithCode("download from %s failed", ProvisionException.REPOSITORY_FAILED_READ,
+					toDownload, e));
 		} finally {
-			if (DEBUG_REQUESTS) {
+			if (debug) {
 				logger.debug("Total number of requests: " + requests.longValue() + " (" + indexRequests.longValue()
 						+ " for p2.index)");
 			}
@@ -264,4 +269,9 @@ private static IStatus reportStatus(IStatus status, OutputStream target) {
 		return status;
 	}
 
+	private static Status statusWithCode(String message, int code, URI source, Exception causingException) {
+		return new Status(IStatus.ERROR, TychoRepositoryTransport.class, code, String.format(message, source),
+				causingException);
+	}
+
 }