Improve GOAWAY handling

Currently GOAWAY is detected/handled only in the connection phase but
sometimes can happen in the transfer phase as well.

This now wraps the whole request inside a block that is retried if a
GOAWAY is detected.

(cherry picked from commit deb31c7)

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

@@ -0,0 +1,59 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Christoph Läubrich and others.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tycho.p2maven.transport;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.util.List;
+import java.util.Map;
+
+public interface Headers extends AutoCloseable {
+
+	String ENCODING_IDENTITY = "identity";
+	String HEADER_ACCEPT_ENCODING = "Accept-Encoding";
+	String HEADER_CONTENT_ENCODING = "Content-Encoding";
+	String ENCODING_GZIP = "gzip";
+	String ETAG_HEADER = "ETag";
+	String LAST_MODIFIED_HEADER = "Last-Modified";
+	String EXPIRES_HEADER = "Expires";
+	String CACHE_CONTROL_HEADER = "Cache-Control";
+	String MAX_AGE_DIRECTIVE = "max-age";
+	String MUST_REVALIDATE_DIRECTIVE = "must-revalidate";
+
+	int statusCode() throws IOException;
+
+	Map<String, List<String>> headers();
+
+	@Override
+	void close();
+
+	URI getURI();
+
+	String getHeader(String header);
+
+	long getLastModified();
+
+	default void checkResponseCode() throws FileNotFoundException, IOException {
+		int code = statusCode();
+		if (code >= HttpURLConnection.HTTP_BAD_REQUEST) {
+			if (code == HttpURLConnection.HTTP_NOT_FOUND || code == HttpURLConnection.HTTP_GONE) {
+				throw new FileNotFoundException(getURI().toString());
+			} else {
+				throw new java.io.IOException("Server returned HTTP code: " + code + " for URL " + getURI().toString());
+			}
+		}
+	}
+
+}

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

@@ -1,14 +1,15 @@
 package org.eclipse.tycho.p2maven.transport;
 
 import java.io.IOException;
-import java.io.InputStream;
+
+import org.eclipse.tycho.p2maven.transport.Response.ResponseConsumer;
 
 public interface HttpTransport {
 
 	void setHeader(String key, String value);
 
-	Response<InputStream> get() throws IOException;
+	<T> T get(ResponseConsumer<T> consumer) throws IOException;
 
-	Response<Void> head() throws IOException;
+	Headers head() throws IOException;
 
 }

p2-maven-plugin/src/main/java/org/eclipse/tycho/p2maven/transport/Java11HttpTransportFactory.java

@@ -15,6 +15,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InterruptedIOException;
+import java.io.OutputStream;
 import java.net.Proxy;
 import java.net.ProxySelector;
 import java.net.SocketAddress;
@@ -42,6 +43,7 @@
 import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable;
 import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException;
 import org.eclipse.tycho.p2maven.helper.ProxyHelper;
+import org.eclipse.tycho.p2maven.transport.Response.ResponseConsumer;
 
 /**
  * A transport using Java11 HttpClient
@@ -77,7 +79,7 @@ public class Java11HttpTransportFactory implements HttpTransportFactory, Initial
 	@Override
 	public HttpTransport createTransport(URI uri) {
 		Java11HttpTransport transport = new Java11HttpTransport(client, clientHttp1, HttpRequest.newBuilder().uri(uri),
-				logger);
+				uri, logger);
 		authenticator.preemtiveAuth((k, v) -> transport.setHeader(k, v), uri);
 		return transport;
 	}
@@ -88,11 +90,13 @@ private static final class Java11HttpTransport implements HttpTransport {
 		private HttpClient client;
 		private Logger logger;
 		private HttpClient clientHttp1;
+		private URI uri;
 
-		public Java11HttpTransport(HttpClient client, HttpClient clientHttp1, Builder builder, Logger logger) {
+		public Java11HttpTransport(HttpClient client, HttpClient clientHttp1, Builder builder, URI uri, Logger logger) {
 			this.client = client;
 			this.clientHttp1 = clientHttp1;
 			this.builder = builder;
+			this.uri = uri;
 			this.logger = logger;
 		}
 
@@ -102,78 +106,106 @@ public void setHeader(String key, String value) {
 		}
 
 		@Override
-		public Response<InputStream> get() throws IOException {
+		public <T> T get(ResponseConsumer<T> consumer) throws IOException {
 			try {
-				HttpResponse<InputStream> response = performGet();
-				return new ResponseImplementation<>(response) {
-
-					@Override
-					public void close() {
-						if (response.version() == Version.HTTP_1_1) {
-							// discard any remaining data and close the stream to return the connection to
-							// the pool..
-							try (InputStream stream = body()) {
-								int discarded = 0;
-								while (discarded < MAX_DISCARD) {
-									int read = stream.read(DUMMY_BUFFER);
-									if (read < 0) {
-										break;
-									}
-									discarded += read;
-								}
-							} catch (IOException e) {
-								// don't care...
-							}
-						} else {
-							// just closing should be enough to signal to the framework...
-							try (InputStream stream = body()) {
-							} catch (IOException e) {
-								// don't care...
-							}
-						}
+				try {
+					return performGet(consumer, client);
+				} catch (IOException e) {
+					if (isGoaway(e)) {
+						logger.info("Received GOAWAY from server " + uri.getHost() + " will retry with Http/1...");
+						TimeUnit.SECONDS.sleep(1);
+						return performGet(consumer, clientHttp1);
 					}
-				};
+					throw e;
+				}
 			} catch (InterruptedException e) {
 				throw new InterruptedIOException();
 			}
 		}
 
-		private HttpResponse<InputStream> performGet() throws IOException, InterruptedException {
+		private <T> T performGet(ResponseConsumer<T> consumer, HttpClient httpClient)
+				throws IOException, InterruptedException {
 			HttpRequest request = builder.GET().timeout(Duration.ofSeconds(TIMEOUT_SECONDS)).build();
-			try {
-				return client.send(request, BodyHandlers.ofInputStream());
-			} catch (IOException e) {
-				if (isGoaway(e)) {
-					logger.warn("Received GOAWAY from server " + request.uri().getHost()
-							+ " will retry after one second with Http/1...");
-					TimeUnit.SECONDS.sleep(1);
-					return clientHttp1.send(request, BodyHandlers.ofInputStream());
+			HttpResponse<InputStream> response = httpClient.send(request, BodyHandlers.ofInputStream());
+			try (ResponseImplementation<InputStream> implementation = new ResponseImplementation<>(response) {
+
+				@Override
+				public void close() {
+					if (response.version() == Version.HTTP_1_1) {
+						// discard any remaining data and close the stream to return the connection to
+						// the pool..
+						try (InputStream stream = response.body()) {
+							int discarded = 0;
+							while (discarded < MAX_DISCARD) {
+								int read = stream.read(DUMMY_BUFFER);
+								if (read < 0) {
+									break;
+								}
+								discarded += read;
+							}
+						} catch (IOException e) {
+							// don't care...
+						}
+					} else {
+						// just closing should be enough to signal to the framework...
+						try (InputStream stream = response.body()) {
+						} catch (IOException e) {
+							// don't care...
+						}
+					}
 				}
-				throw e;
+
+				@Override
+				public void transferTo(OutputStream outputStream, ContentEncoding transportEncoding)
+						throws IOException {
+					transportEncoding.decode(response.body()).transferTo(outputStream);
+				}
+			}) {
+				return consumer.handleResponse(implementation);
 			}
 		}
 
 		@Override
-		public Response<Void> head() throws IOException {
+		public Response head() throws IOException {
 			try {
-				HttpResponse<Void> response = client.send(
-						builder.method("HEAD", BodyPublishers.noBody()).timeout(Duration.ofSeconds(TIMEOUT_SECONDS))
-								.build(),
-						BodyHandlers.discarding());
-				return new ResponseImplementation<>(response) {
-					@Override
-					public void close() {
-						// nothing...
+				try {
+					return doHead(client);
+				} catch (IOException e) {
+					if (isGoaway(e)) {
+						logger.debug("Received GOAWAY from server " + uri.getHost()
+								+ " will retry with Http/1...");
+						TimeUnit.SECONDS.sleep(1);
+						return doHead(clientHttp1);
 					}
-				};
+					throw e;
+				}
 			} catch (InterruptedException e) {
 				throw new InterruptedIOException();
 			}
 		}
 
+		private Response doHead(HttpClient httpClient) throws IOException, InterruptedException {
+			HttpResponse<Void> response = httpClient.send(
+					builder.method("HEAD", BodyPublishers.noBody()).timeout(Duration.ofSeconds(TIMEOUT_SECONDS))
+							.build(),
+					BodyHandlers.discarding());
+			return new ResponseImplementation<>(response) {
+				@Override
+				public void close() {
+					// nothing...
+				}
+
+				@Override
+				public void transferTo(OutputStream outputStream, ContentEncoding transportEncoding)
+						throws IOException {
+					throw new IOException("HEAD returns no body");
+				}
+			};
+		}
+
 	}
 
-	private static abstract class ResponseImplementation<T> implements Response<T> {
+	private static abstract class ResponseImplementation<T> implements Response {
 		private final HttpResponse<T> response;
 
 		private ResponseImplementation(HttpResponse<T> response) {
@@ -190,11 +222,6 @@ public Map<String, List<String>> headers() {
 			return response.headers().map();
 		}
 
-		@Override
-		public T body() {
-			return response.body();
-		}
-
 		@Override
 		public String getHeader(String header) {
 			return response.headers().firstValue(header).orElse(null);

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

@@ -12,39 +12,32 @@
  *******************************************************************************/
 package org.eclipse.tycho.p2maven.transport;
 
-import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.net.HttpURLConnection;
-import java.net.URI;
-import java.util.List;
-import java.util.Map;
-
-public interface Response<T> extends AutoCloseable {
-
-	int statusCode() throws IOException;
-
-	Map<String, List<String>> headers();
-
-	@Override
-	void close();
-
-	T body() throws IOException;
-
-	URI getURI();
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.zip.GZIPInputStream;
+
+public interface Response extends Headers {
+
+	default void transferTo(OutputStream outputStream) throws IOException {
+		String encoding = getHeader(Headers.HEADER_CONTENT_ENCODING);
+		if (Headers.ENCODING_GZIP.equals(encoding)) {
+			transferTo(outputStream, GZIPInputStream::new);
+		} else if (encoding == null || encoding.isEmpty() || Headers.ENCODING_IDENTITY.equals(encoding)) {
+			transferTo(outputStream, stream -> stream);
+		} else {
+			throw new IOException("Unknown content encoding: " + encoding);
+		}
+	}
 
-	String getHeader(String header);
+	void transferTo(OutputStream outputStream, ContentEncoding transportEncoding) throws IOException;
 
-	long getLastModified();
+	interface ContentEncoding {
+		InputStream decode(InputStream raw) throws IOException;
+	}
 
-	default void checkResponseCode() throws FileNotFoundException, IOException {
-		int code = statusCode();
-		if (code >= HttpURLConnection.HTTP_BAD_REQUEST) {
-			if (code == HttpURLConnection.HTTP_NOT_FOUND || code == HttpURLConnection.HTTP_GONE) {
-				throw new FileNotFoundException(getURI().toString());
-			} else {
-				throw new java.io.IOException("Server returned HTTP code: " + code + " for URL " + getURI().toString());
-			}
-		}
+	interface ResponseConsumer<T> {
+		T handleResponse(Response response) throws IOException;
 	}
 
 }