Create a load testing EPP client (#2415)

* Create a load testing EPP client.

This code is mostly based off of what was used for a past EPP load testing client that can be found in Google3 at https://source.corp.google.com/piper///depot/google3/experimental/users/jianglai/proxy/java/google/registry/proxy/client/

I modified the old client to be open-source friendly and use Gradle.

For now, this only performs a login and logout command, I will further expand on this in later PRs to add other EPP commands so that we can truly load test the system.

* Small changes

* Remove unnecessary build dep

* Add gradle build tasks

* Small fixes

* Add an instances setUp and cleanUp script

* More modifications to instance setup scripts

* change to ubuntu instance

* Add comment to make ssh work

load-testing/src/main/java/google/registry/client/EppClientHandler.java

@@ -0,0 +1,153 @@
+// Copyright 2024 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.client;
+
+import static google.registry.client.EppClient.CHANNEL_NUMBER;
+import static google.registry.client.EppClient.FORCE_TERMINATE;
+import static google.registry.client.EppClient.INPUT_ITERATOR;
+import static google.registry.client.EppClient.LOGGING_EXECUTOR;
+import static google.registry.client.EppClient.LOGGING_LOCATION;
+import static google.registry.client.EppClient.LOGGING_REQUEST_COMPLETE;
+import static google.registry.client.EppClient.REQUEST_SENT;
+import static google.registry.client.EppClient.RESPONSE_RECEIVED;
+import static java.nio.file.StandardOpenOption.APPEND;
+
+import com.google.common.flogger.FluentLogger;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandler.Sharable;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.util.ReferenceCountUtil;
+import io.netty.util.concurrent.Promise;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+
+/** Handler that sends EPP requests and receives EPP responses. */
+@SuppressWarnings("FutureReturnValueIgnored")
+@Sharable
+public class EppClientHandler extends ChannelDuplexHandler {
+
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  static class FileWriter implements Runnable {
+
+    private final Path loggingLocation;
+    private final byte[] contents;
+    private final ZonedDateTime time;
+
+    FileWriter(Path loggingLocation, byte[] contents, ZonedDateTime time) {
+      this.loggingLocation = loggingLocation;
+      this.contents = contents;
+      this.time = time;
+    }
+
+    @Override
+    public void run() {
+      try {
+        if (!Files.exists(loggingLocation)) {
+          Files.createFile(loggingLocation);
+        }
+        Files.writeString(loggingLocation, time.toString() + "\n", APPEND);
+        Files.write(loggingLocation, contents, APPEND);
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+    }
+  }
+
+  @Override
+  public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
+    ZonedDateTime now = ZonedDateTime.now(ZoneOffset.UTC);
+    ctx.channel().attr(REQUEST_SENT).get().add(now);
+    ctx.channel().attr(LOGGING_REQUEST_COMPLETE).set(ctx.executor().newPromise());
+    super.channelRegistered(ctx);
+  }
+
+  @Override
+  public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
+    Promise<Void> loggingCompletePromise = ctx.channel().attr(LOGGING_REQUEST_COMPLETE).get();
+    if (!loggingCompletePromise.isDone()) {
+      loggingCompletePromise.setSuccess(null);
+    }
+    logger.atWarning().withCause(cause).log(
+        "Connection %d closed.", ctx.channel().attr(CHANNEL_NUMBER).get());
+  }
+
+  @Override
+  public void channelRead(ChannelHandlerContext ctx, Object msg) {
+    ZonedDateTime now = ZonedDateTime.now(ZoneOffset.UTC);
+    Channel ch = ctx.channel();
+    ctx.channel().attr(RESPONSE_RECEIVED).get().add(now);
+    if (msg instanceof ByteBuf buffer) {
+      byte[] contents = new byte[buffer.readableBytes()];
+      buffer.readBytes(contents);
+      ReferenceCountUtil.release(buffer);
+      if (ch.attr(LOGGING_LOCATION).get() != null) {
+        ch.attr(LOGGING_EXECUTOR)
+            .get()
+            .submit(new FileWriter(ch.attr(LOGGING_LOCATION).get(), contents, now));
+      }
+      if (ch.attr(INPUT_ITERATOR).get().hasNext()) {
+        ch.writeAndFlush(ch.attr(INPUT_ITERATOR).get().next());
+      } else {
+        ch.attr(LOGGING_REQUEST_COMPLETE).get().setSuccess(null);
+        if (ch.attr(FORCE_TERMINATE).get()) {
+          ch.close();
+        }
+      }
+    }
+  }
+
+  @Override
+  public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
+    ZonedDateTime now = ZonedDateTime.now(ZoneOffset.UTC);
+    Channel ch = ctx.channel();
+    ctx.channel().attr(REQUEST_SENT).get().add(now);
+    if (msg instanceof byte[] outputBytes) {
+      ByteBuf buffer = Unpooled.buffer();
+      buffer.writeBytes(outputBytes);
+      ctx.write(buffer, promise);
+      if (ch.attr(LOGGING_LOCATION).get() != null) {
+        ch.attr(LOGGING_EXECUTOR)
+            .get()
+            .submit(new FileWriter(ch.attr(LOGGING_LOCATION).get(), outputBytes, now));
+      }
+    }
+  }
+
+  @Override
+  public void close(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+    Promise<Void> loggingCompletePromise = ctx.channel().attr(LOGGING_REQUEST_COMPLETE).get();
+    if (!loggingCompletePromise.isDone()) {
+      loggingCompletePromise.setSuccess(null);
+    }
+    super.close(ctx, promise);
+  }
+
+  @Override
+  public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+    Promise<Void> loggingCompletePromise = ctx.channel().attr(LOGGING_REQUEST_COMPLETE).get();
+    if (!loggingCompletePromise.isDone()) {
+      loggingCompletePromise.setSuccess(null);
+    }
+    super.channelInactive(ctx);
+  }
+}