Throw error for Netty when Jetty ALPN not configured.

netty/src/main/java/io/grpc/transport/netty/JettyAlpnVerifier.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2015, Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package io.grpc.transport.netty;
+
+/**
+ * Utility class that verifies that Jetty ALPN is properly configured for the system.
+ */
+final class JettyAlpnVerifier {
+  private JettyAlpnVerifier() {
+  }
+
+  /**
+   * Exception thrown when Jetty ALPN was not found in the boot classloader.
+   */
+  static final class NotFoundException extends Exception {
+    public NotFoundException(Throwable cause) {
+      super("Jetty ALPN not found in boot classloader.", cause);
+    }
+  }
+
+  /**
+   * Verifies that Jetty ALPN is configured properly on this system.
+   * @throws NotFoundException thrown if Jetty ALPN is missing from the boot classloader.
+   */
+  static void verifyJettyAlpn() throws NotFoundException {
+    try {
+      // Check the boot classloader for the ALPN class.
+      Class.forName("org.eclipse.jetty.alpn.ALPN", true, null);
+    } catch (ClassNotFoundException e) {
+      throw new NotFoundException(e);
+    }
+  }
+}

netty/src/main/java/io/grpc/transport/netty/ProtocolNegotiators.java

@@ -48,6 +48,8 @@ import io.netty.handler.codec.http.HttpMethod;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http2.Http2ClientUpgradeCodec;
 import io.netty.handler.codec.http2.Http2ConnectionHandler;
+import io.netty.handler.ssl.OpenSslContext;
+import io.netty.handler.ssl.OpenSslEngine;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslHandler;
 import io.netty.handler.ssl.SslHandshakeCompletionEvent;
@@ -78,6 +80,16 @@ public final class ProtocolNegotiators {
    */
   public static ChannelHandler serverTls(SSLEngine sslEngine) {
     Preconditions.checkNotNull(sslEngine, "sslEngine");
+
+    // If we're using Jetty ALPN, verify that it is configured properly.
+    if (!(sslEngine instanceof OpenSslEngine)) {
+      try {
+        JettyAlpnVerifier.verifyJettyAlpn();
+      } catch (JettyAlpnVerifier.NotFoundException e) {
+        throw new IllegalArgumentException(e);
+      }
+    }
+
     return new SslHandler(sslEngine, false);
   }
 
@@ -91,6 +103,15 @@ public final class ProtocolNegotiators {
     Preconditions.checkNotNull(sslContext, "sslContext");
     Preconditions.checkNotNull(inetAddress, "inetAddress");
 
+    // If we're using Jetty ALPN, verify that it is configured properly.
+    if (!(sslContext instanceof OpenSslContext)) {
+      try {
+        JettyAlpnVerifier.verifyJettyAlpn();
+      } catch (JettyAlpnVerifier.NotFoundException e) {
+        throw new IllegalArgumentException(e);
+      }
+    }
+
     return new ProtocolNegotiator() {
       @Override
       public Handler newHandler(Http2ConnectionHandler handler) {