ZOOKEEPER-4835: Make use of Netty optional when no SSL is used

pom.xml

@@ -561,6 +561,7 @@
     <commons-io.version>2.17.0</commons-io.version>
     <burningwave.mockdns.version>0.27.2</burningwave.mockdns.version>
     <dnsjava.version>3.5.1</dnsjava.version>
+    <archunit.version>1.4.2</archunit.version>
     <clover-maven-plugin.version>4.4.1</clover-maven-plugin.version>
     <sonar-maven-plugin.version>3.7.0.1746</sonar-maven-plugin.version>
     <maven.min.version>3.5.0</maven.min.version>
@@ -693,6 +694,12 @@
         <artifactId>mockito-core</artifactId>
         <version>${mockito.version}</version>
       </dependency>
+      <dependency>
+        <groupId>com.tngtech.archunit</groupId>
+        <artifactId>archunit-junit5</artifactId>
+        <version>${archunit.version}</version>
+        <scope>test</scope>
+      </dependency>
       <dependency>
         <groupId>io.netty</groupId>
         <artifactId>netty-bom</artifactId>

zookeeper-assembly/pom.xml

@@ -115,6 +115,21 @@
       <groupId>org.xerial.snappy</groupId>
       <artifactId>snappy-java</artifactId>
     </dependency>
+    <!-- Netty is an optional dependency of zookeeper-server but should be
+         included in the server distribution for SSL/TLS support. -->
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-handler</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-transport-native-epoll</artifactId>
+      <classifier>linux-x86_64</classifier>
+    </dependency>
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-tcnative-boringssl-static</artifactId>
+    </dependency>
   </dependencies>
 
   <build>

zookeeper-server/pom.xml

@@ -65,15 +65,18 @@
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-handler</artifactId>
+      <optional>true</optional>
     </dependency>
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-transport-native-epoll</artifactId>
       <classifier>linux-x86_64</classifier>
+      <optional>true</optional>
     </dependency>
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-tcnative-boringssl-static</artifactId>
+      <optional>true</optional>
     </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>
@@ -175,6 +178,11 @@
       <artifactId>tools</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.tngtech.archunit</groupId>
+      <artifactId>archunit-junit5</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.xerial.snappy</groupId>
       <artifactId>snappy-java</artifactId>

zookeeper-server/src/main/java/org/apache/zookeeper/ClientCnxnSocketNetty.java

@@ -51,7 +51,7 @@
 import org.apache.zookeeper.ClientCnxn.EndOfStreamException;
 import org.apache.zookeeper.ClientCnxn.Packet;
 import org.apache.zookeeper.client.ZKClientConfig;
-import org.apache.zookeeper.common.ClientX509Util;
+import org.apache.zookeeper.common.ClientNettyX509Util;
 import org.apache.zookeeper.common.NettyUtils;
 import org.apache.zookeeper.common.X509Exception;
 import org.slf4j.Logger;
@@ -446,7 +446,7 @@ private synchronized void initSSL(ChannelPipeline pipeline)
             throws X509Exception.SSLContextException, X509Exception.KeyManagerException,
                    X509Exception.TrustManagerException, SSLException {
             if (sslContext == null) {
-                try (ClientX509Util x509Util = new ClientX509Util()) {
+                try (ClientNettyX509Util x509Util = new ClientNettyX509Util()) {
                     sslContext = x509Util.createNettySslContextForClient(clientConfig);
                 }
             }

zookeeper-server/src/main/java/org/apache/zookeeper/ZooKeeper.java

@@ -3141,20 +3141,34 @@ protected SocketAddress testableLocalSocketAddress() {
     }
 
     private ClientCnxnSocket getClientCnxnSocket() throws IOException {
+        // Derived from a same-package class rather than a string literal so the shade plugin relocates it.
+        final String nettyClientCnxnSocketName = ClientCnxnSocketNIO.class.getPackageName() + ".ClientCnxnSocketNetty";
         String clientCnxnSocketName = getClientConfig().getProperty(ZKClientConfig.ZOOKEEPER_CLIENT_CNXN_SOCKET);
-        if (clientCnxnSocketName == null || clientCnxnSocketName.equals(ClientCnxnSocketNIO.class.getSimpleName())) {
+        if (clientCnxnSocketName == null) {
+            boolean secureClient = getClientConfig().getBoolean(ZKClientConfig.SECURE_CLIENT);
+            if (secureClient) {
+                clientCnxnSocketName = nettyClientCnxnSocketName;
+            } else {
+                clientCnxnSocketName = ClientCnxnSocketNIO.class.getName();
+            }
+        } else if (clientCnxnSocketName.equals(ClientCnxnSocketNIO.class.getSimpleName())) {
             clientCnxnSocketName = ClientCnxnSocketNIO.class.getName();
-        } else if (clientCnxnSocketName.equals(ClientCnxnSocketNetty.class.getSimpleName())) {
-            clientCnxnSocketName = ClientCnxnSocketNetty.class.getName();
+        } else if (clientCnxnSocketName.equals("ClientCnxnSocketNetty")) {
+            clientCnxnSocketName = nettyClientCnxnSocketName;
         }
 
         try {
             Constructor<?> clientCxnConstructor = Class.forName(clientCnxnSocketName)
                                                        .getDeclaredConstructor(ZKClientConfig.class);
             ClientCnxnSocket clientCxnSocket = (ClientCnxnSocket) clientCxnConstructor.newInstance(getClientConfig());
             return clientCxnSocket;
-        } catch (Exception e) {
-            throw new IOException("Couldn't instantiate " + clientCnxnSocketName, e);
+        } catch (Exception | NoClassDefFoundError e) {
+            String msg = "Couldn't instantiate " + clientCnxnSocketName;
+            if (getClientConfig().getBoolean(ZKClientConfig.SECURE_CLIENT)) {
+                msg += ". SSL/TLS support requires Netty; please add netty-handler"
+                    + " (and optionally netty-tcnative-boringssl-static) to your project's dependencies.";
+            }
+            throw new IOException(msg, e);
         }
     }
 

zookeeper-server/src/main/java/org/apache/zookeeper/cli/HexDumpOutputFormatter.java

@@ -18,17 +18,45 @@
 
 package org.apache.zookeeper.cli;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.Unpooled;
-
 public class HexDumpOutputFormatter implements OutputFormatter {
 
     public static final HexDumpOutputFormatter INSTANCE = new HexDumpOutputFormatter();
 
+    private static final int BYTES_PER_ROW = 16;
+    private static final int ASCII_PRINTABLE_MIN = 0x20; // space
+    private static final int ASCII_PRINTABLE_MAX = 0x7f; // DEL (exclusive)
+    private static final String LINE_SEPARATOR = System.lineSeparator();
+    private static final String HEADER_LINE =
+        "         +-------------------------------------------------+" + LINE_SEPARATOR
+        + "         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |" + LINE_SEPARATOR
+        + "+--------+-------------------------------------------------+----------------+";
+    private static final String FOOTER_LINE =
+        "+--------+-------------------------------------------------+----------------+";
+
     @Override
     public String format(byte[] data) {
-        ByteBuf buf = Unpooled.wrappedBuffer(data);
-        return ByteBufUtil.prettyHexDump(buf);
+        if (data == null || data.length == 0) {
+            return "";
+        }
+        StringBuilder sb = new StringBuilder();
+        sb.append(HEADER_LINE).append(LINE_SEPARATOR);
+        for (int offset = 0; offset < data.length; offset += BYTES_PER_ROW) {
+            sb.append(String.format("|%08x|", offset));
+            StringBuilder charPart = new StringBuilder();
+            for (int i = 0; i < BYTES_PER_ROW; i++) {
+                if (offset + i < data.length) {
+                    int b = data[offset + i] & 0xFF;
+                    sb.append(String.format(" %02x", b));
+                    char c = (char) b;
+                    charPart.append(c >= ASCII_PRINTABLE_MIN && c < ASCII_PRINTABLE_MAX ? c : '.');
+                } else {
+                    sb.append("   ");
+                    charPart.append(' ');
+                }
+            }
+            sb.append(" |").append(charPart).append("|").append(LINE_SEPARATOR);
+        }
+        sb.append(FOOTER_LINE);
+        return sb.toString();
     }
 }