chore(implementation)!: use Jetty-12 core without servlets

Port the invoker to upgrade to Eclipse Jetty-12 version 12.  Specifically using the new core APIs of Eclipse Jetty-12 that allow the overhead of a Servlet container to be avoided.

BREAKING CHANGE: use Java 17 or above, as required by Eclipse Jetty-12.

Author: gregw

invoker/core/src/main/java/com/google/cloud/functions/invoker/http/HttpRequestImpl.java

@@ -14,8 +14,6 @@
 
 package com.google.cloud.functions.invoker.http;
 
-import static java.util.stream.Collectors.toMap;
-
 import com.google.cloud.functions.HttpRequest;
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -25,14 +23,15 @@
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.TreeMap;
 import java.util.concurrent.ExecutionException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.StreamSupport;
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpHeader;
@@ -41,10 +40,12 @@
 import org.eclipse.jetty.http.MultiPartFormData;
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.server.Request;
-import org.eclipse.jetty.util.Fields.Field;
+import org.eclipse.jetty.util.Fields;
 
 public class HttpRequestImpl implements HttpRequest {
   private final Request request;
+  private InputStream inputStream;
+  private BufferedReader reader;
 
   public HttpRequestImpl(Request request) {
     this.request = request;
@@ -72,9 +73,15 @@ public Optional<String> getQuery() {
 
   @Override
   public Map<String, List<String>> getQueryParameters() {
+    Fields fields = Request.extractQueryParameters(request);
+    if (fields.isEmpty()) {
+      return Collections.emptyMap();
+    }
 
-    return Request.extractQueryParameters(request).stream()
-        .collect(toMap(Field::getName, Field::getValues));
+    Map<String, List<String>> map = new HashMap<>();
+    fields.forEach(field -> map.put(field.getName(),
+        Collections.unmodifiableList(field.getValues())));
+    return Collections.unmodifiableMap(map);
   }
 
   @Override
@@ -94,9 +101,14 @@ public Map<String, HttpPart> getParts() {
             parser.setMaxMemoryFileSize(-1);
             return parser.parse(request);
           }).get();
-      return StreamSupport.stream(parts.spliterator(), false)
-          .map(HttpPartImpl::new)
-          .collect(toMap(HttpPartImpl::getName, p -> p));
+
+      if (parts.size() == 0) {
+        return Collections.emptyMap();
+      }
+
+      Map<String, HttpPart> map = new HashMap<>();
+      parts.forEach(part -> map.put(part.getName(), new HttpPartImpl(part)));
+      return Collections.unmodifiableMap(map);
     } catch (InterruptedException | ExecutionException e) {
       throw new RuntimeException(e);
     }
@@ -118,9 +130,6 @@ public Optional<String> getCharacterEncoding() {
     return Optional.ofNullable(charset == null ? null : charset.name());
   }
 
-  private InputStream inputStream;
-  private BufferedReader reader;
-
   @Override
   public InputStream getInputStream() throws IOException {
     if (reader != null) {

invoker/core/src/main/java/com/google/cloud/functions/invoker/http/HttpResponseImpl.java

@@ -21,8 +21,6 @@
 import java.io.OutputStream;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -34,6 +32,8 @@
 
 public class HttpResponseImpl implements HttpResponse {
   private final Response response;
+  private OutputStream outputStream;
+  private BufferedWriter writer;
 
   public HttpResponseImpl(Response response) {
     this.response = response;
@@ -70,13 +70,6 @@ public Map<String, List<String>> getHeaders() {
     return HttpRequestImpl.toStringListMap(response.getHeaders());
   }
 
-  private static <T> List<T> list(Collection<T> collection) {
-    return (collection instanceof List<?>) ? (List<T>) collection : new ArrayList<>(collection);
-  }
-
-  private OutputStream outputStream;
-  private BufferedWriter writer;
-
   @Override
   public OutputStream getOutputStream() {
     if (writer != null) {

invoker/core/src/main/java/com/google/cloud/functions/invoker/runner/Invoker.java

@@ -54,7 +54,6 @@
 import org.eclipse.jetty.server.Response;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.ServerConnector;
-import org.eclipse.jetty.server.handler.ContextHandler;
 import org.eclipse.jetty.server.handler.ErrorHandler;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.thread.QueuedThreadPool;
@@ -234,7 +233,7 @@ ClassLoader getFunctionClassLoader() {
    * unit or integration test, use {@link #startTestServer()} instead.
    *
    * @see #stopServer()
-   * @throws Exception
+   * @throws Exception If there was a problem starting the server
    */
   public void startServer() throws Exception {
     startServer(true);
@@ -266,7 +265,7 @@ public void startServer() throws Exception {
    * }</pre>
    *
    * @see #stopServer()
-   * @throws Exception
+   * @throws Exception If there was a problem starting the server
    */
   public void startTestServer() throws Exception {
     startServer(false);
@@ -292,15 +291,13 @@ public boolean handle(Request request, Response response, Callback callback) {
     connector.setReuseAddress(true);
     connector.setReusePort(true);
     server.setConnectors(new Connector[] {connector});
-
-    ContextHandler contextHandler = new ContextHandler("/");
-    server.setHandler(NotFoundHandler.forServlet(contextHandler));
+    server.setHandler(new NotFoundHandler());
 
     Class<?> functionClass = loadFunctionClass();
 
     Handler handler;
     if (functionSignatureType == null) {
-      handler = servletForDeducedSignatureType(functionClass);
+      handler = handlerForDeducedSignatureType(functionClass);
     } else {
       switch (functionSignatureType) {
         case "http":
@@ -327,8 +324,6 @@ public boolean handle(Request request, Response response, Callback callback) {
       }
     }
 
-    // TODO servletHolder.getRegistration().setMultipartConfig(new MultipartConfigElement(""));
-
     server.getTail().setHandler(handler);
     server.start();
     logServerInfo();
@@ -376,7 +371,7 @@ private Class<?> loadFunctionClass() throws ClassNotFoundException {
     }
   }
 
-  private Handler servletForDeducedSignatureType(Class<?> functionClass) {
+  private Handler handlerForDeducedSignatureType(Class<?> functionClass) {
     if (HttpFunction.class.isAssignableFrom(functionClass)) {
       return HttpFunctionExecutor.forClass(functionClass);
     }
@@ -456,16 +451,11 @@ private static boolean isGcf() {
 
   /**
    * Wrapper that intercepts requests for {@code /favicon.ico} and {@code /robots.txt} and causes
-   * them to produce a 404 status. Otherwise they would be sent to the function code, like any other
+   * them to produce a 404 status. Otherwise, they would be sent to the function code, like any other
    * URL, meaning that someone testing their function by using a browser as an HTTP client can see
    * two requests, one for {@code /favicon.ico} and one for {@code /} (or whatever).
    */
   private static class NotFoundHandler extends Handler.Wrapper {
-    static NotFoundHandler forServlet(ContextHandler servletHandler) {
-      NotFoundHandler handler = new NotFoundHandler();
-      handler.setHandler(servletHandler);
-      return handler;
-    }
 
     private static final Set<String> NOT_FOUND_PATHS =
         new HashSet<>(Arrays.asList("/favicon.ico", "/robots.txt"));
@@ -507,7 +497,6 @@ private static class OnlyApiClassLoader extends ClassLoader {
     protected Class<?> findClass(String name) throws ClassNotFoundException {
       String prefix = "com.google.cloud.functions.";
       if ((name.startsWith(prefix) && Character.isUpperCase(name.charAt(prefix.length())))
-          || name.startsWith("javax.servlet.")
           || isCloudEventsApiClass(name)) {
         return runtimeClassLoader.loadClass(name);
       }

invoker/core/src/test/java/com/google/cloud/functions/invoker/http/HttpTest.java

@@ -93,7 +93,6 @@ private static class SimpleServer implements AutoCloseable {
     SimpleServer(Handler handler) throws Exception {
       this.server = new Server(serverPort);
       server.setHandler(handler);
-      // TODO servletHolder.getRegistration().setMultipartConfig(new MultipartConfigElement("tiddly"));
       server.start();
     }