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.   Several optimizations are included, including the optimization that small writes can be buffered in such a way to avoid chunked responses when possible.

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/HttpResponseImpl.java

@@ -93,9 +93,7 @@ public synchronized BufferedWriter getWriter() throws IOException {
     return writer;
   }
 
-  /**
-   * Close the response, flushing all content.
-   */
+  /** Close the response, flushing all content. */
   public void close() {
     try {
       IO.close(getOutputStream());
@@ -109,13 +107,11 @@ public void close() {
   }
 
   /**
-   * A {@link BufferedWriter} that does not buffer.
-   * It is generally more efficient to buffer at the lower level,
-   * since frequently total content is smaller than a single buffer and
-   * the lower level buffer can turn a close into a last write that will avoid
-   * chunking the response if at all possible.   However, {@link BufferedWriter}
-   * is in the API for {@link HttpResponse}, so we must return a writer of
-   * that type.
+   * A {@link BufferedWriter} that does not buffer. It is generally more efficient to buffer at the
+   * lower level, since frequently total content is smaller than a single buffer and the lower level
+   * buffer can turn a close into a last write that will avoid chunking the response if at all
+   * possible. However, {@link BufferedWriter} is in the API for {@link HttpResponse}, so we must
+   * return a writer of that type.
    */
   private static class NonBufferedWriter extends BufferedWriter {
     private final Writer writer;

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

@@ -448,8 +448,8 @@ 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 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).
+   * 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 HandlerWrapper {
 

invoker/core/src/test/java/com/google/cloud/functions/invoker/IntegrationTest.java

@@ -253,8 +253,7 @@ public void helloWorld() throws Exception {
         fullTarget("HelloWorld"),
         ImmutableList.of(
             TestCase.builder()
-                .setExpectedResponseHeaders(ImmutableMap.of(
-                    "Content-Length", "*"))
+                .setExpectedResponseHeaders(ImmutableMap.of("Content-Length", "*"))
                 .setExpectedResponseText("hello\n")
                 .build(),
             FAVICON_TEST_CASE,
@@ -271,23 +270,23 @@ public void bufferedWrites() throws Exception {
             TestCase.builder()
                 .setUrl("/target?writes=2")
                 .setExpectedResponseText("write 0\nwrite 1\n")
-                .setExpectedResponseHeaders(ImmutableMap.of(
-                    "x-write-0", "true",
-                    "x-write-1", "true",
-                    "x-written", "true",
-                    "Content-Length", "16"
-                ))
+                .setExpectedResponseHeaders(
+                    ImmutableMap.of(
+                        "x-write-0", "true",
+                        "x-write-1", "true",
+                        "x-written", "true",
+                        "Content-Length", "16"))
                 .build(),
             TestCase.builder()
                 .setUrl("/target?writes=2&flush=true")
                 .setExpectedResponseText("write 0\nwrite 1\n")
-                .setExpectedResponseHeaders(ImmutableMap.of(
-                    "x-write-0", "true",
-                    "x-write-1", "true",
-                    "x-written", "-",
-                    "Transfer-Encoding", "chunked"))
-                .build()
-        ));
+                .setExpectedResponseHeaders(
+                    ImmutableMap.of(
+                        "x-write-0", "true",
+                        "x-write-1", "true",
+                        "x-written", "-",
+                        "Transfer-Encoding", "chunked"))
+                .build()));
   }
 
   @Test
@@ -728,17 +727,26 @@ private void testFunction(
             .withMessage("Response to %s is %s %s", uri, response.getStatus(), response.getReason())
             .that(response.getStatus())
             .isEqualTo(testCase.expectedResponseCode());
-        testCase.expectedResponseHeaders().ifPresent(map -> {
-          for (Map.Entry<String, String> entry : map.entrySet()) {
-            if ("*".equals(entry.getValue())) {
-              expect.that(response.getHeaders().getFieldNamesCollection()).contains(entry.getKey());
-            } else if ("-".equals(entry.getValue())) {
-              expect.that(response.getHeaders().getFieldNamesCollection()).doesNotContain(entry.getKey());
-            } else {
-              expect.that(response.getHeaders().getValuesList(entry.getKey())).contains(entry.getValue());
-            }
-          }
-        });
+        testCase
+            .expectedResponseHeaders()
+            .ifPresent(
+                map -> {
+                  for (Map.Entry<String, String> entry : map.entrySet()) {
+                    if ("*".equals(entry.getValue())) {
+                      expect
+                          .that(response.getHeaders().getFieldNamesCollection())
+                          .contains(entry.getKey());
+                    } else if ("-".equals(entry.getValue())) {
+                      expect
+                          .that(response.getHeaders().getFieldNamesCollection())
+                          .doesNotContain(entry.getKey());
+                    } else {
+                      expect
+                          .that(response.getHeaders().getValuesList(entry.getKey()))
+                          .contains(entry.getValue());
+                    }
+                  }
+                });
         testCase
             .expectedResponseText()
             .ifPresent(text -> expect.that(response.getContentAsString()).isEqualTo(text));