From 5b6a9fde32ab697fc0bd741e20acab40286c0dc9 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 12 Apr 2024 16:24:23 +0900
Subject: [PATCH 01/24] refactor: remove the Force shutdown mode

---
 .../armeria/server/AbstractHttpResponseHandler.java        | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/AbstractHttpResponseHandler.java b/core/src/main/java/com/linecorp/armeria/server/AbstractHttpResponseHandler.java
index 43a229e3330..12d5b4d0f0e 100644
--- a/core/src/main/java/com/linecorp/armeria/server/AbstractHttpResponseHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/AbstractHttpResponseHandler.java
@@ -56,7 +56,6 @@ abstract class AbstractHttpResponseHandler {
 
     private final CompletableFuture<Void> completionFuture;
     private boolean isComplete;
-    private boolean needsDisconnection;
 
     AbstractHttpResponseHandler(ChannelHandlerContext ctx,
                                 ServerHttpObjectEncoder responseEncoder,
@@ -77,7 +76,6 @@ boolean isDone() {
     }
 
     void disconnectWhenFinished() {
-        needsDisconnection = true;
         responseEncoder.keepAliveHandler().disconnectWhenFinished();
     }
 
@@ -92,11 +90,6 @@ final boolean tryComplete(@Nullable Throwable cause) {
             completionFuture.completeExceptionally(cause);
         }
 
-        // Force shutdown mode: If a user explicitly sets `Connection: close` in the response headers, it is
-        // assumed that the connection should be closed after sending the response.
-        if (needsDisconnection) {
-            ctx.channel().close();
-        }
         return true;
     }
 

From f01ca8ab80e658c9055208ee60b439f81df14c0e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 12 Apr 2024 16:51:20 +0900
Subject: [PATCH 02/24] feat: create a schedule for waiting and closing in
 HTTP1

---
 .../java/com/linecorp/armeria/server/HttpServerHandler.java   | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index 9bab1110bd9..9358c50909a 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -780,7 +780,9 @@ private void handleRequestOrResponseComplete() {
                         // Stop receiving new requests.
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
-                            ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
+                            ctx.executor().schedule(() ->
+                                            ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE),
+                                            1000, TimeUnit.MILLISECONDS);
                         }
                     }
                 }

From 824bb23827ebaf629f578a813d14a28ebcc8106e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 08:37:41 +0900
Subject: [PATCH 03/24] feat: define a defaultHttp1ConnectionCloseDelayMillis
 Flag

---
 .../armeria/common/DefaultFlagsProvider.java  |  6 ++++++
 .../com/linecorp/armeria/common/Flags.java    | 19 +++++++++++++++++++
 .../armeria/common/FlagsProvider.java         | 16 ++++++++++++++++
 .../common/SystemPropertyFlagsProvider.java   |  5 +++++
 4 files changed, 46 insertions(+)

diff --git a/core/src/main/java/com/linecorp/armeria/common/DefaultFlagsProvider.java b/core/src/main/java/com/linecorp/armeria/common/DefaultFlagsProvider.java
index be234e7e625..067ffb25eec 100644
--- a/core/src/main/java/com/linecorp/armeria/common/DefaultFlagsProvider.java
+++ b/core/src/main/java/com/linecorp/armeria/common/DefaultFlagsProvider.java
@@ -93,6 +93,7 @@ final class DefaultFlagsProvider implements FlagsProvider {
     static final String FILE_SERVICE_CACHE_SPEC = "maximumSize=1024";
     static final String DNS_CACHE_SPEC = "maximumSize=4096";
     static final long DEFAULT_UNHANDLED_EXCEPTIONS_REPORT_INTERVAL_MILLIS = 10000;
+    static final long DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS = 3000;
 
     private DefaultFlagsProvider() {}
 
@@ -479,4 +480,9 @@ public Long defaultUnhandledExceptionsReportIntervalMillis() {
     public DistributionStatisticConfig distributionStatisticConfig() {
         return DistributionStatisticConfigUtil.DEFAULT_DIST_STAT_CFG;
     }
+
+    @Override
+    public Long defaultHttp1ConnectionCloseDelayMillis() {
+        return DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS;
+    }
 }
diff --git a/core/src/main/java/com/linecorp/armeria/common/Flags.java b/core/src/main/java/com/linecorp/armeria/common/Flags.java
index 58e7041189b..43f54d8f6f3 100644
--- a/core/src/main/java/com/linecorp/armeria/common/Flags.java
+++ b/core/src/main/java/com/linecorp/armeria/common/Flags.java
@@ -412,6 +412,10 @@ private static boolean validateTransportType(TransportType transportType, String
     private static final DistributionStatisticConfig DISTRIBUTION_STATISTIC_CONFIG =
             getValue(FlagsProvider::distributionStatisticConfig, "distributionStatisticConfig");
 
+    private static final long DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS =
+            getValue(FlagsProvider::defaultHttp1ConnectionCloseDelayMillis,
+                    "defaultHttp1ConnectionCloseDelayMillis", value -> value >= 0);
+
     /**
      * Returns the specification of the {@link Sampler} that determines whether to retain the stack
      * trace of the exceptions that are thrown frequently by Armeria. A sampled exception will have the stack
@@ -1539,6 +1543,21 @@ public static DistributionStatisticConfig distributionStatisticConfig() {
         return DISTRIBUTION_STATISTIC_CONFIG;
     }
 
+    /**
+     * Returns the default time in milliseconds to wait before closing an HTTP1 connection when a server needs
+     * to close the connection. This allows to avoid a server socket from remaining in the TIME_WAIT state
+     * instead of CLOSED when a connection is closed.
+     *
+     * <p>The default value of this flag is
+     * {@value DefaultFlagsProvider#DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS}. Specify the
+     * {@code -Dcom.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis=<long>} JVM option to
+     * override the default value.</p>
+     */
+    @UnstableApi
+    public static long defaultHttp1ConnectionCloseDelayMillis() {
+        return DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS;
+    }
+
     @Nullable
     private static String nullableCaffeineSpec(Function<FlagsProvider, String> method, String flagName) {
         return caffeineSpec(method, flagName, true);
diff --git a/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java b/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
index e2b606fc1c2..496d66dde3a 100644
--- a/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
+++ b/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
@@ -1159,4 +1159,20 @@ default Long defaultUnhandledExceptionsReportIntervalMillis() {
     default DistributionStatisticConfig distributionStatisticConfig() {
         return null;
     }
+
+    /**
+     * Returns the default time in milliseconds to wait before closing an HTTP1 connection when a server needs
+     * to close the connection. This allows to avoid a server socket from remaining in the TIME_WAIT state
+     * instead of CLOSED when a connection is closed.
+     *
+     * <p>The default value of this flag is
+     * {@value DefaultFlagsProvider#DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS}. Specify the
+     * {@code -Dcom.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis=<long>} JVM option to
+     * override the default value.</p>
+     */
+    @Nullable
+    @UnstableApi
+    default Long defaultHttp1ConnectionCloseDelayMillis() {
+        return null;
+    }
 }
diff --git a/core/src/main/java/com/linecorp/armeria/common/SystemPropertyFlagsProvider.java b/core/src/main/java/com/linecorp/armeria/common/SystemPropertyFlagsProvider.java
index d1b3411fbd1..f34057eee6e 100644
--- a/core/src/main/java/com/linecorp/armeria/common/SystemPropertyFlagsProvider.java
+++ b/core/src/main/java/com/linecorp/armeria/common/SystemPropertyFlagsProvider.java
@@ -492,6 +492,11 @@ public Long defaultUnhandledExceptionsReportIntervalMillis() {
         return getLong("defaultUnhandledExceptionsReportIntervalMillis");
     }
 
+    @Override
+    public Long defaultHttp1ConnectionCloseDelayMillis() {
+        return getLong("defaultHttp1ConnectionCloseDelayMillis");
+    }
+
     @Nullable
     private static Long getLong(String name) {
         return getAndParse(name, Long::parseLong);

From 1d764aadcf84f7b938e190bd29d2ba347e20f28e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 08:40:02 +0900
Subject: [PATCH 04/24] refactor: replace hardcoded
 defaultHttp1ConnectionCloseDelayMillis with the flag

---
 .../java/com/linecorp/armeria/server/HttpServerHandler.java  | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index 9358c50909a..b7e5e021217 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -35,6 +35,7 @@
 
 import javax.net.ssl.SSLSession;
 
+import com.linecorp.armeria.common.Flags;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -781,8 +782,8 @@ private void handleRequestOrResponseComplete() {
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
                             ctx.executor().schedule(() ->
-                                            ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE),
-                                            1000, TimeUnit.MILLISECONDS);
+                                        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE),
+                                        Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
                         }
                     }
                 }

From 5820fe9a12b459caacc43a069ee50fa57eefc3cb Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 08:53:18 +0900
Subject: [PATCH 05/24] fix: to schedule the close connection task to run in
 the channel's event loop

---
 .../java/com/linecorp/armeria/server/HttpServerHandler.java     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index b7e5e021217..82631365467 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -781,7 +781,7 @@ private void handleRequestOrResponseComplete() {
                         // Stop receiving new requests.
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
-                            ctx.executor().schedule(() ->
+                            ctx.channel().eventLoop().schedule(() ->
                                         ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE),
                                         Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
                         }

From 4a7f0efdb37f05fba6faf8b91d970984f421c3ee Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 09:20:38 +0900
Subject: [PATCH 06/24] refactor: fix import order

---
 .../java/com/linecorp/armeria/server/HttpServerHandler.java     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index 82631365467..dbb6481f4fd 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -35,12 +35,12 @@
 
 import javax.net.ssl.SSLSession;
 
-import com.linecorp.armeria.common.Flags;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import com.linecorp.armeria.common.AggregationOptions;
 import com.linecorp.armeria.common.ClosedSessionException;
+import com.linecorp.armeria.common.Flags;
 import com.linecorp.armeria.common.HttpData;
 import com.linecorp.armeria.common.HttpHeaderNames;
 import com.linecorp.armeria.common.HttpMethod;

From 90b5509da1094ee5314ce4de9a2c2cf555951720 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 18:12:42 +0900
Subject: [PATCH 07/24] test: set defaultHttp1ConnectionCloseDelayMillis to 0
 on HttpServerPathTest

---
 .../java/com/linecorp/armeria/server/HttpServerPathTest.java   | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java b/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
index 922a8763892..9557480d446 100644
--- a/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
@@ -26,6 +26,7 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
+import org.junitpioneer.jupiter.SetSystemProperty;
 
 import com.google.common.io.ByteStreams;
 
@@ -36,6 +37,8 @@
 
 import io.netty.util.NetUtil;
 
+// Allow the server to close the socket immediately, without waiting for the client to close
+@SetSystemProperty(key = "com.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis", value = "0")
 class HttpServerPathTest {
 
     @RegisterExtension

From ae86f290e440450deb5ea45499832ff15a3a1348 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Wed, 24 Apr 2024 18:14:24 +0900
Subject: [PATCH 08/24] feat: check the active status of a channel before
 running a close task

---
 .../com/linecorp/armeria/server/HttpServerHandler.java    | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index dbb6481f4fd..c4278b1c640 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -781,9 +781,11 @@ private void handleRequestOrResponseComplete() {
                         // Stop receiving new requests.
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
-                            ctx.channel().eventLoop().schedule(() ->
-                                        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE),
-                                        Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
+                            ctx.channel().eventLoop().schedule(() -> {
+                                    if (ctx.channel().isActive()) {
+                                        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
+                                    }
+                                }, Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
                         }
                     }
                 }

From e74d1825fc27147b1e11a70baf0be732ec96ce01 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Thu, 25 Apr 2024 19:20:19 +0900
Subject: [PATCH 09/24] test: read only a first line in HttpServerPathTest to
 does not wait for the server to close the connection

---
 .../linecorp/armeria/server/HttpServerPathTest.java | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java b/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
index 9557480d446..f685f1d020f 100644
--- a/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/HttpServerPathTest.java
@@ -18,6 +18,8 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
 import java.net.Socket;
 import java.nio.charset.StandardCharsets;
 import java.util.LinkedHashMap;
@@ -26,9 +28,6 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
-import org.junitpioneer.jupiter.SetSystemProperty;
-
-import com.google.common.io.ByteStreams;
 
 import com.linecorp.armeria.common.HttpResponse;
 import com.linecorp.armeria.common.HttpStatus;
@@ -37,8 +36,6 @@
 
 import io.netty.util.NetUtil;
 
-// Allow the server to close the socket immediately, without waiting for the client to close
-@SetSystemProperty(key = "com.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis", value = "0")
 class HttpServerPathTest {
 
     @RegisterExtension
@@ -124,7 +121,11 @@ private static void urlPathAssertion(HttpStatus expected, String path) throws Ex
         try (Socket s = new Socket(NetUtil.LOCALHOST, server.httpPort())) {
             s.setSoTimeout(10000);
             s.getOutputStream().write(requestString.getBytes(StandardCharsets.US_ASCII));
-            assertThat(new String(ByteStreams.toByteArray(s.getInputStream()), StandardCharsets.US_ASCII))
+            final BufferedReader in = new BufferedReader(
+                    new InputStreamReader(s.getInputStream(), StandardCharsets.US_ASCII));
+            // only reads a first line because it only needs to check the expected status
+            // and does not wait for the server to close the connection
+            assertThat(in.readLine())
                     .as(path)
                     .startsWith("HTTP/1.1 " + expected);
         }

From 4ec928d58d07748e527606d737c212cdfe20c7cb Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 10:31:01 +0900
Subject: [PATCH 10/24] test: implement test cases for
 Http1ServerDelayedCloseConnectionTest

---
 ...Http1ServerDelayedCloseConnectionTest.java | 150 ++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
new file mode 100644
index 00000000000..b87c0baab6c
--- /dev/null
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright 2022 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you 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:
+ *
+ *   https://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 com.linecorp.armeria.server;
+
+import com.linecorp.armeria.common.Flags;
+import com.linecorp.armeria.common.HttpHeaderNames;
+import com.linecorp.armeria.common.HttpResponse;
+
+import com.linecorp.armeria.testing.junit5.server.ServerExtension;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.net.BindException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.time.Duration;
+import java.util.Random;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class Http1ServerDelayedCloseConnectionTest {
+
+    @RegisterExtension
+    static ServerExtension server = new ServerExtension() {
+        @Override
+        protected void configure(ServerBuilder sb) {
+            sb.idleTimeoutMillis(0);
+            sb.http(0);
+            sb.https(0);
+            sb.tlsSelfSigned();
+            sb.service("/close", (ctx, req) -> {
+                return HttpResponse.builder()
+                        .ok()
+                        .content("OK\n")
+                        .header(HttpHeaderNames.CONNECTION, "close")
+                        .build();
+            });
+        }
+    };
+
+
+    @Test
+    void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() throws IOException {
+        Random random = new Random();
+        short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
+            socket.setReuseAddress(true);
+            socket.setSoTimeout(100000);
+            final PrintWriter writer = new PrintWriter(socket.getOutputStream());
+            writer.print("GET /close" + " HTTP/1.1\r\n");
+            writer.print("\r\n");
+            writer.flush();
+
+            final BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+            assertThat(in.readLine()).isEqualTo("HTTP/1.1 200 OK");
+
+            String line;
+            boolean hasConnectionClose = false;
+            while ((line = in.readLine()) != null) {
+                if ("connection: close".equalsIgnoreCase(line)) {
+                    hasConnectionClose = true;
+                }
+                if (line.isEmpty() || line.contains(":")) {
+                    continue;
+                }
+                if (line.startsWith("OK")) {
+                    break;
+                }
+            }
+            long readStartTimestamp = System.nanoTime();
+            int readResult = in.read();
+            long readDurationMillis = Duration.ofNanos(System.nanoTime() - readStartTimestamp).toMillis();
+
+            assertThat(hasConnectionClose).isTrue();
+            assertThat(readResult).isEqualTo(-1);
+
+            long defaultHttp1ConnectionCloseDelayMillis = Flags.defaultHttp1ConnectionCloseDelayMillis();
+            assertThat(readDurationMillis).isBetween(
+                    defaultHttp1ConnectionCloseDelayMillis - 100,
+                    defaultHttp1ConnectionCloseDelayMillis + 1000
+            );
+
+            socket.close();
+            Socket reuseSock = new Socket();
+            reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort));
+            reuseSock.close();
+        }
+    }
+
+    @Test
+    void shouldWaitForDisconnectByClientSideFirst() throws IOException {
+        Random random = new Random();
+        short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
+            socket.setReuseAddress(true);
+            socket.setSoTimeout(1000);
+            final PrintWriter writer = new PrintWriter(socket.getOutputStream());
+            writer.print("GET /close" + " HTTP/1.1\r\n");
+            writer.print("\r\n");
+            writer.flush();
+
+            final BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+            assertThat(in.readLine()).isEqualTo("HTTP/1.1 200 OK");
+
+            String line;
+            boolean hasConnectionClose = false;
+            while ((line = in.readLine()) != null) {
+                if ("connection: close".equalsIgnoreCase(line)) {
+                    hasConnectionClose = true;
+                }
+                if (line.isEmpty() || line.contains(":")) {
+                    continue;
+                }
+                if (line.startsWith("OK")) {
+                    break;
+                }
+            }
+            assertThat(hasConnectionClose).isTrue();
+            assertThat(server.server().numConnections()).isEqualTo(1);
+
+            socket.close();
+            Socket reuseSock = new Socket();
+            assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
+                    .isInstanceOf(BindException.class)
+                    .hasMessageContaining("Address already in use");
+            reuseSock.close();
+            assertThat(server.server().numConnections()).isZero();
+        }
+    }
+}

From abbfc56d298ecc151c2c969f931c9db41c7975ef Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 10:44:37 +0900
Subject: [PATCH 11/24] test: fix lint errors

---
 ...Http1ServerDelayedCloseConnectionTest.java | 41 +++++++++----------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index b87c0baab6c..73fa6f8b6db 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 LINE Corporation
+ * Copyright 2024 LINE Corporation
  *
  * LINE Corporation licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -16,13 +16,8 @@
 
 package com.linecorp.armeria.server;
 
-import com.linecorp.armeria.common.Flags;
-import com.linecorp.armeria.common.HttpHeaderNames;
-import com.linecorp.armeria.common.HttpResponse;
-
-import com.linecorp.armeria.testing.junit5.server.ServerExtension;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.extension.RegisterExtension;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -35,8 +30,13 @@
 import java.time.Duration;
 import java.util.Random;
 
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import com.linecorp.armeria.common.Flags;
+import com.linecorp.armeria.common.HttpHeaderNames;
+import com.linecorp.armeria.common.HttpResponse;
+import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
 class Http1ServerDelayedCloseConnectionTest {
 
@@ -58,11 +58,10 @@ protected void configure(ServerBuilder sb) {
         }
     };
 
-
     @Test
     void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() throws IOException {
-        Random random = new Random();
-        short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
+        final Random random = new Random();
+        final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
             socket.setReuseAddress(true);
             socket.setSoTimeout(100000);
@@ -87,21 +86,21 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
                     break;
                 }
             }
-            long readStartTimestamp = System.nanoTime();
-            int readResult = in.read();
-            long readDurationMillis = Duration.ofNanos(System.nanoTime() - readStartTimestamp).toMillis();
+            final long readStartTimestamp = System.nanoTime();
+            final int readResult = in.read();
+            final long readDurationMillis = Duration.ofNanos(System.nanoTime() - readStartTimestamp).toMillis();
 
             assertThat(hasConnectionClose).isTrue();
             assertThat(readResult).isEqualTo(-1);
 
-            long defaultHttp1ConnectionCloseDelayMillis = Flags.defaultHttp1ConnectionCloseDelayMillis();
+            final long defaultHttp1ConnectionCloseDelayMillis = Flags.defaultHttp1ConnectionCloseDelayMillis();
             assertThat(readDurationMillis).isBetween(
                     defaultHttp1ConnectionCloseDelayMillis - 100,
                     defaultHttp1ConnectionCloseDelayMillis + 1000
             );
 
             socket.close();
-            Socket reuseSock = new Socket();
+            final Socket reuseSock = new Socket();
             reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort));
             reuseSock.close();
         }
@@ -109,8 +108,8 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
 
     @Test
     void shouldWaitForDisconnectByClientSideFirst() throws IOException {
-        Random random = new Random();
-        short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
+        final Random random = new Random();
+        final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
             socket.setReuseAddress(true);
             socket.setSoTimeout(1000);
@@ -139,7 +138,7 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
             assertThat(server.server().numConnections()).isEqualTo(1);
 
             socket.close();
-            Socket reuseSock = new Socket();
+            final Socket reuseSock = new Socket();
             assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
                     .isInstanceOf(BindException.class)
                     .hasMessageContaining("Address already in use");

From f2c64e6a11f95bd4b8adb9951ffbc601b57acdc8 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 12:31:39 +0900
Subject: [PATCH 12/24] test: remove setReuseAddress(true) from
 Http1ServerDelayedCloseConnectionTest

---
 .../server/Http1ServerDelayedCloseConnectionTest.java       | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 73fa6f8b6db..b60a4795c6a 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -17,6 +17,7 @@
 package com.linecorp.armeria.server;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.io.BufferedReader;
@@ -63,7 +64,6 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
         final Random random = new Random();
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
-            socket.setReuseAddress(true);
             socket.setSoTimeout(100000);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
@@ -101,7 +101,8 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
 
             socket.close();
             final Socket reuseSock = new Socket();
-            reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort));
+            assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
+                    .doesNotThrowAnyException();
             reuseSock.close();
         }
     }
@@ -111,7 +112,6 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
         final Random random = new Random();
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
-            socket.setReuseAddress(true);
             socket.setSoTimeout(1000);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");

From 29308ddf481c5eca97f73b07c80d3477389e1d3c Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 13:25:28 +0900
Subject: [PATCH 13/24] test: add await().untilAsserted to wait for server to
 close the connection

---
 .../armeria/server/Http1ServerDelayedCloseConnectionTest.java  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index b60a4795c6a..0d665fd6fad 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -19,6 +19,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.awaitility.Awaitility.await;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -143,7 +144,7 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
                     .isInstanceOf(BindException.class)
                     .hasMessageContaining("Address already in use");
             reuseSock.close();
-            assertThat(server.server().numConnections()).isZero();
+            await().untilAsserted(() -> assertThat(server.server().numConnections()).isZero());
         }
     }
 }

From a0c178751493abf6c276147dc28ee05a102f53f2 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 13:58:10 +0900
Subject: [PATCH 14/24] test: set socket.setReuseAddress(false) to
 Http1ServerDelayedCloseConnectionTest

---
 .../armeria/server/Http1ServerDelayedCloseConnectionTest.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 0d665fd6fad..d8311360409 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -66,6 +66,7 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
             socket.setSoTimeout(100000);
+            socket.setReuseAddress(false);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");
@@ -113,7 +114,8 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
         final Random random = new Random();
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
-            socket.setSoTimeout(1000);
+            socket.setSoTimeout(100000);
+            socket.setReuseAddress(false);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");

From f966235394790afae82b154b2bf30795d01e45db Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 15:39:20 +0900
Subject: [PATCH 15/24] test: set socket.setReuseAddress(false) to reuseSock in
 Http1ServerDelayedCloseConnectionTest

---
 .../armeria/server/Http1ServerDelayedCloseConnectionTest.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index d8311360409..1910388d3a6 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -66,7 +66,6 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
             socket.setSoTimeout(100000);
-            socket.setReuseAddress(false);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");
@@ -103,6 +102,7 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
 
             socket.close();
             final Socket reuseSock = new Socket();
+            reuseSock.setReuseAddress(false);
             assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
                     .doesNotThrowAnyException();
             reuseSock.close();
@@ -115,7 +115,6 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
         try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
             socket.setSoTimeout(100000);
-            socket.setReuseAddress(false);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");
@@ -142,6 +141,7 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
 
             socket.close();
             final Socket reuseSock = new Socket();
+            reuseSock.setReuseAddress(false);
             assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
                     .isInstanceOf(BindException.class)
                     .hasMessageContaining("Address already in use");

From e0155d7b7f2ea3ba598d27be697e789867b199c0 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 26 Apr 2024 16:33:30 +0900
Subject: [PATCH 16/24] test: make the bind socket test run only in linux and
 macos

---
 ...Http1ServerDelayedCloseConnectionTest.java | 32 +++++++++++--------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 1910388d3a6..180b93030ba 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -32,6 +32,8 @@
 import java.time.Duration;
 import java.util.Random;
 
+import com.linecorp.armeria.common.util.OsType;
+import com.linecorp.armeria.common.util.SystemInfo;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
@@ -100,12 +102,14 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
                     defaultHttp1ConnectionCloseDelayMillis + 1000
             );
 
-            socket.close();
-            final Socket reuseSock = new Socket();
-            reuseSock.setReuseAddress(false);
-            assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
-                    .doesNotThrowAnyException();
-            reuseSock.close();
+            // Additional test to check that the socket is in the CLOSED state
+            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.WINDOWS) {
+                socket.close();
+                try(Socket reuseSock = new Socket()) {
+                    assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
+                            .doesNotThrowAnyException();
+                }
+            }
         }
     }
 
@@ -139,13 +143,15 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
             assertThat(hasConnectionClose).isTrue();
             assertThat(server.server().numConnections()).isEqualTo(1);
 
-            socket.close();
-            final Socket reuseSock = new Socket();
-            reuseSock.setReuseAddress(false);
-            assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
-                    .isInstanceOf(BindException.class)
-                    .hasMessageContaining("Address already in use");
-            reuseSock.close();
+            // Additional test to check that the socket is in the TIMED_WAIT state
+            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.WINDOWS) {
+                socket.close();
+                try(Socket reuseSock = new Socket()) {
+                    assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
+                            .isInstanceOf(BindException.class)
+                            .hasMessageContaining("Address already in use");
+                }
+            }
             await().untilAsserted(() -> assertThat(server.server().numConnections()).isZero());
         }
     }

From 5e25804d67d657927b0b372c1db70f5414ce474e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Tue, 30 Apr 2024 13:11:36 +0900
Subject: [PATCH 17/24] test: make the bind socket test run only in linux and
 macos

---
 .../armeria/server/Http1ServerDelayedCloseConnectionTest.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 180b93030ba..3e0cecdfde1 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -103,7 +103,7 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
             );
 
             // Additional test to check that the socket is in the CLOSED state
-            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.WINDOWS) {
+            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
                 socket.close();
                 try(Socket reuseSock = new Socket()) {
                     assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
@@ -144,7 +144,7 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
             assertThat(server.server().numConnections()).isEqualTo(1);
 
             // Additional test to check that the socket is in the TIMED_WAIT state
-            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.WINDOWS) {
+            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
                 socket.close();
                 try(Socket reuseSock = new Socket()) {
                     assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))

From 151ff7a7c3834ef07fbc12543e1afc38b710c04a Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Fri, 3 May 2024 22:28:34 +0900
Subject: [PATCH 18/24] lint: apply code style

---
 .../armeria/server/HttpServerHandler.java     |  8 ++++----
 ...Http1ServerDelayedCloseConnectionTest.java | 19 ++++++++++---------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index 5ad7e65ff47..301fb0a2d36 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -796,10 +796,10 @@ private void handleRequestOrResponseComplete() {
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
                             ctx.channel().eventLoop().schedule(() -> {
-                                    if (ctx.channel().isActive()) {
-                                        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
-                                    }
-                                }, Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
+                                if (ctx.channel().isActive()) {
+                                    ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
+                                }
+                            }, Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
                         }
                     }
                 }
diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 3e0cecdfde1..ddc00edcbf3 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -54,10 +54,10 @@ protected void configure(ServerBuilder sb) {
             sb.tlsSelfSigned();
             sb.service("/close", (ctx, req) -> {
                 return HttpResponse.builder()
-                        .ok()
-                        .content("OK\n")
-                        .header(HttpHeaderNames.CONNECTION, "close")
-                        .build();
+                                   .ok()
+                                   .content("OK\n")
+                                   .header(HttpHeaderNames.CONNECTION, "close")
+                                   .build();
             });
         }
     };
@@ -66,7 +66,7 @@ protected void configure(ServerBuilder sb) {
     void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() throws IOException {
         final Random random = new Random();
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
-        try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort(), null, localPort)) {
             socket.setSoTimeout(100000);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
@@ -105,7 +105,7 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
             // Additional test to check that the socket is in the CLOSED state
             if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
                 socket.close();
-                try(Socket reuseSock = new Socket()) {
+                try (Socket reuseSock = new Socket()) {
                     assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
                             .doesNotThrowAnyException();
                 }
@@ -117,7 +117,7 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
     void shouldWaitForDisconnectByClientSideFirst() throws IOException {
         final Random random = new Random();
         final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
-        try (Socket socket = new Socket("127.0.0.1", server.httpPort(),  null, localPort)) {
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort(), null, localPort)) {
             socket.setSoTimeout(100000);
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
@@ -146,8 +146,9 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
             // Additional test to check that the socket is in the TIMED_WAIT state
             if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
                 socket.close();
-                try(Socket reuseSock = new Socket()) {
-                    assertThatThrownBy(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
+                try (Socket reuseSock = new Socket()) {
+                    assertThatThrownBy(
+                            () -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
                             .isInstanceOf(BindException.class)
                             .hasMessageContaining("Address already in use");
                 }

From 12a536d518b2872e6e96f4236c5f77c34097a29d Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Mon, 6 May 2024 20:15:28 +0900
Subject: [PATCH 19/24] feat: make closing connection immediately when the
 response was already sent on HTTP1.1

---
 .../com/linecorp/armeria/server/Http1RequestDecoder.java    | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/Http1RequestDecoder.java b/core/src/main/java/com/linecorp/armeria/server/Http1RequestDecoder.java
index a46616be294..edfea9224ae 100644
--- a/core/src/main/java/com/linecorp/armeria/server/Http1RequestDecoder.java
+++ b/core/src/main/java/com/linecorp/armeria/server/Http1RequestDecoder.java
@@ -321,7 +321,11 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
                         req = null;
                         final boolean shouldReset;
                         if (encoder instanceof ServerHttp1ObjectEncoder) {
-                            keepAliveHandler.disconnectWhenFinished();
+                            if (encoder.isResponseHeadersSent(id, 1)) {
+                                ctx.channel().close();
+                            } else {
+                                keepAliveHandler.disconnectWhenFinished();
+                            }
                             shouldReset = false;
                         } else {
                             // Upgraded to HTTP/2. Reset only if the remote peer is still open.

From bbc35b710e8085142f25abd6955387c290820d9e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Mon, 6 May 2024 22:24:37 +0900
Subject: [PATCH 20/24] feat: fix to not use random port

---
 ...Http1ServerDelayedCloseConnectionTest.java | 43 ++++++++-----------
 1 file changed, 17 insertions(+), 26 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index ddc00edcbf3..fb2c1a4d753 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -30,10 +30,7 @@
 import java.net.InetSocketAddress;
 import java.net.Socket;
 import java.time.Duration;
-import java.util.Random;
 
-import com.linecorp.armeria.common.util.OsType;
-import com.linecorp.armeria.common.util.SystemInfo;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
@@ -64,10 +61,9 @@ protected void configure(ServerBuilder sb) {
 
     @Test
     void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() throws IOException {
-        final Random random = new Random();
-        final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
-        try (Socket socket = new Socket("127.0.0.1", server.httpPort(), null, localPort)) {
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort())) {
             socket.setSoTimeout(100000);
+            final int socketPort = socket.getLocalPort();
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");
@@ -102,23 +98,19 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
                     defaultHttp1ConnectionCloseDelayMillis + 1000
             );
 
-            // Additional test to check that the socket is in the CLOSED state
-            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
-                socket.close();
-                try (Socket reuseSock = new Socket()) {
-                    assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
-                            .doesNotThrowAnyException();
-                }
+            socket.close();
+            try (Socket reuseSock = new Socket()) {
+                assertThatCode(() -> reuseSock.bind(new InetSocketAddress((InetAddress) null, socketPort)))
+                        .doesNotThrowAnyException();
             }
         }
     }
 
     @Test
     void shouldWaitForDisconnectByClientSideFirst() throws IOException {
-        final Random random = new Random();
-        final short localPort = (short) random.nextInt(Short.MAX_VALUE + 1);
-        try (Socket socket = new Socket("127.0.0.1", server.httpPort(), null, localPort)) {
+        try (Socket socket = new Socket("127.0.0.1", server.httpPort())) {
             socket.setSoTimeout(100000);
+            final int socketPort = socket.getLocalPort();
             final PrintWriter writer = new PrintWriter(socket.getOutputStream());
             writer.print("GET /close" + " HTTP/1.1\r\n");
             writer.print("\r\n");
@@ -143,16 +135,15 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
             assertThat(hasConnectionClose).isTrue();
             assertThat(server.server().numConnections()).isEqualTo(1);
 
-            // Additional test to check that the socket is in the TIMED_WAIT state
-            if (SystemInfo.osType() == OsType.LINUX || SystemInfo.osType() == OsType.MAC) {
-                socket.close();
-                try (Socket reuseSock = new Socket()) {
-                    assertThatThrownBy(
-                            () -> reuseSock.bind(new InetSocketAddress((InetAddress) null, localPort)))
-                            .isInstanceOf(BindException.class)
-                            .hasMessageContaining("Address already in use");
-                }
-            }
+            socket.close();
+            assertThatThrownBy(
+                    () -> {
+                        final Socket reuseSock = new Socket("127.0.0.1", server.httpPort(), null, socketPort);
+                        reuseSock.close();
+                    })
+                    .isInstanceOf(BindException.class)
+                    .hasMessageContaining("Address already in use");
+
             await().untilAsserted(() -> assertThat(server.server().numConnections()).isZero());
         }
     }

From 32cda15d49ed50ae1fcbb6bfa632d719fd9ffcd5 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Thu, 9 May 2024 21:07:30 +0900
Subject: [PATCH 21/24] test: refactor to read each line

---
 ...Http1ServerDelayedCloseConnectionTest.java | 44 +++++++------------
 1 file changed, 15 insertions(+), 29 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index fb2c1a4d753..0e37ccd2243 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -71,25 +71,17 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
 
             final BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
             assertThat(in.readLine()).isEqualTo("HTTP/1.1 200 OK");
-
-            String line;
-            boolean hasConnectionClose = false;
-            while ((line = in.readLine()) != null) {
-                if ("connection: close".equalsIgnoreCase(line)) {
-                    hasConnectionClose = true;
-                }
-                if (line.isEmpty() || line.contains(":")) {
-                    continue;
-                }
-                if (line.startsWith("OK")) {
-                    break;
-                }
-            }
+            in.readLine(); // content-type
+            in.readLine(); // content-length
+            in.readLine(); // server
+            in.readLine(); // date
+            assertThat(in.readLine()).isEqualToIgnoringCase("connection: close");
+            assertThat(in.readLine()).isEmpty();
+            assertThat(in.readLine()).isEqualToIgnoringCase("OK");
             final long readStartTimestamp = System.nanoTime();
             final int readResult = in.read();
             final long readDurationMillis = Duration.ofNanos(System.nanoTime() - readStartTimestamp).toMillis();
 
-            assertThat(hasConnectionClose).isTrue();
             assertThat(readResult).isEqualTo(-1);
 
             final long defaultHttp1ConnectionCloseDelayMillis = Flags.defaultHttp1ConnectionCloseDelayMillis();
@@ -118,27 +110,21 @@ void shouldWaitForDisconnectByClientSideFirst() throws IOException {
 
             final BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
             assertThat(in.readLine()).isEqualTo("HTTP/1.1 200 OK");
+            in.readLine(); // content-type
+            in.readLine(); // content-length
+            in.readLine(); // server
+            in.readLine(); // date
+            assertThat(in.readLine()).isEqualToIgnoringCase("connection: close");
+            assertThat(in.readLine()).isEmpty();
+            assertThat(in.readLine()).isEqualToIgnoringCase("OK");
 
-            String line;
-            boolean hasConnectionClose = false;
-            while ((line = in.readLine()) != null) {
-                if ("connection: close".equalsIgnoreCase(line)) {
-                    hasConnectionClose = true;
-                }
-                if (line.isEmpty() || line.contains(":")) {
-                    continue;
-                }
-                if (line.startsWith("OK")) {
-                    break;
-                }
-            }
-            assertThat(hasConnectionClose).isTrue();
             assertThat(server.server().numConnections()).isEqualTo(1);
 
             socket.close();
             assertThatThrownBy(
                     () -> {
                         final Socket reuseSock = new Socket("127.0.0.1", server.httpPort(), null, socketPort);
+                        // close the socket in case initializing the socket doesn't throw an exception
                         reuseSock.close();
                     })
                     .isInstanceOf(BindException.class)

From 83d7ba2e1796911afcfbbd6b9a6b08f07596cdc7 Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Thu, 9 May 2024 21:25:03 +0900
Subject: [PATCH 22/24] docs: clarify the server closes the connection
 immediately when defaultHttp1ConnectionCloseDelayMillis is 0

---
 core/src/main/java/com/linecorp/armeria/common/Flags.java     | 4 ++--
 .../main/java/com/linecorp/armeria/common/FlagsProvider.java  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/common/Flags.java b/core/src/main/java/com/linecorp/armeria/common/Flags.java
index 43f54d8f6f3..822b1fd974d 100644
--- a/core/src/main/java/com/linecorp/armeria/common/Flags.java
+++ b/core/src/main/java/com/linecorp/armeria/common/Flags.java
@@ -1544,14 +1544,14 @@ public static DistributionStatisticConfig distributionStatisticConfig() {
     }
 
     /**
-     * Returns the default time in milliseconds to wait before closing an HTTP1 connection when a server needs
+     * Returns the default time in milliseconds to wait before closing an HTTP/1 connection when a server needs
      * to close the connection. This allows to avoid a server socket from remaining in the TIME_WAIT state
      * instead of CLOSED when a connection is closed.
      *
      * <p>The default value of this flag is
      * {@value DefaultFlagsProvider#DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS}. Specify the
      * {@code -Dcom.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis=<long>} JVM option to
-     * override the default value.</p>
+     * override the default value. {@code 0} closes the connection immediately.</p>
      */
     @UnstableApi
     public static long defaultHttp1ConnectionCloseDelayMillis() {
diff --git a/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java b/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
index 496d66dde3a..c5c2c027902 100644
--- a/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
+++ b/core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java
@@ -1161,14 +1161,14 @@ default DistributionStatisticConfig distributionStatisticConfig() {
     }
 
     /**
-     * Returns the default time in milliseconds to wait before closing an HTTP1 connection when a server needs
+     * Returns the default time in milliseconds to wait before closing an HTTP/1 connection when a server needs
      * to close the connection. This allows to avoid a server socket from remaining in the TIME_WAIT state
      * instead of CLOSED when a connection is closed.
      *
      * <p>The default value of this flag is
      * {@value DefaultFlagsProvider#DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS}. Specify the
      * {@code -Dcom.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis=<long>} JVM option to
-     * override the default value.</p>
+     * override the default value. {@code 0} closes the connection immediately. </p>
      */
     @Nullable
     @UnstableApi

From 4a9496fc522f21f51bcd0c55ea75e7fca06cd33a Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Thu, 9 May 2024 21:26:27 +0900
Subject: [PATCH 23/24] feat: make the server close the connection immediately
 when defaultHttp1ConnectionCloseDelayMillis is 0

---
 .../armeria/server/HttpServerHandler.java         | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
index 48fdd70cc18..777a5433843 100644
--- a/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
+++ b/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java
@@ -793,11 +793,16 @@ private void handleRequestOrResponseComplete() {
                         // Stop receiving new requests.
                         handledLastRequest = true;
                         if (unfinishedRequests.isEmpty()) {
-                            ctx.channel().eventLoop().schedule(() -> {
-                                if (ctx.channel().isActive()) {
-                                    ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
-                                }
-                            }, Flags.defaultHttp1ConnectionCloseDelayMillis(), TimeUnit.MILLISECONDS);
+                            final long closeDelay = Flags.defaultHttp1ConnectionCloseDelayMillis();
+                            if (closeDelay == 0) {
+                                ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
+                            } else {
+                                ctx.channel().eventLoop().schedule(() -> {
+                                    if (ctx.channel().isActive()) {
+                                        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(CLOSE);
+                                    }
+                                }, closeDelay, TimeUnit.MILLISECONDS);
+                            }
                         }
                     }
                 }

From 3b45ee8fa624978fad5eed510410df426271f98e Mon Sep 17 00:00:00 2001
From: "soyun.seong" <thdbsdox12@gmail.com>
Date: Thu, 9 May 2024 21:31:27 +0900
Subject: [PATCH 24/24] test: increase the duration of the connection closure
 time

---
 .../armeria/server/Http1ServerDelayedCloseConnectionTest.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
index 0e37ccd2243..4096327c32d 100644
--- a/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/Http1ServerDelayedCloseConnectionTest.java
@@ -86,8 +86,8 @@ void shouldDelayDisconnectByServerSideIfClientDoesNotHandleConnectionClose() thr
 
             final long defaultHttp1ConnectionCloseDelayMillis = Flags.defaultHttp1ConnectionCloseDelayMillis();
             assertThat(readDurationMillis).isBetween(
-                    defaultHttp1ConnectionCloseDelayMillis - 100,
-                    defaultHttp1ConnectionCloseDelayMillis + 1000
+                    defaultHttp1ConnectionCloseDelayMillis - 2000,
+                    defaultHttp1ConnectionCloseDelayMillis + 2000
             );
 
             socket.close();