IGNITE-1025 Warn when IP finder has a long list of addresses

modules/core/src/main/java/org/apache/ignite/spi/discovery/tcp/TcpDiscoverySpi.java

@@ -305,6 +305,9 @@ public class TcpDiscoverySpi extends IgniteSpiAdapter implements IgniteDiscovery
     /** Ssl message pattern for StreamCorruptedException. */
     private static Pattern sslMsgPattern = Pattern.compile("invalid stream header: 150\\d0\\d00");
 
+    /** Number of resolved IP finder addresses that triggers a warning about potentially slow node join. */
+    static final int ADDRS_WARN_THRESHOLD = 20;
+
     /** Local address. */
     protected String locAddr;
 
@@ -1964,6 +1967,13 @@ protected Collection<InetSocketAddress> resolvedAddresses() throws IgniteSpiExce
             }
         }
 
+        if (res.size() > ADDRS_WARN_THRESHOLD)
+            LT.warn(log, "Long list of addresses resolved from IP finder: connecting to an unavailable address " +
+                "usually blocks until socket timeout instead of failing fast (on Windows OS this may look like " +
+                "the node hangs for a while), so every unreachable address in the list slows down node join or " +
+                "reconnection. Make sure that all addresses are correct and reachable, consider reducing the " +
+                "address list or increasing 'joinTimeout' to bound the wait [addrsCnt=" + res.size() + "]");
+
         if (!res.isEmpty() && !skipAddrsRandomization)
             Collections.shuffle(res);
 

modules/core/src/test/java/org/apache/ignite/spi/discovery/tcp/TcpDiscoveryLongAddressListWarnSelfTest.java

@@ -0,0 +1,97 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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
+ *
+ *      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 org.apache.ignite.spi.discovery.tcp;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.spi.discovery.tcp.ipfinder.vm.TcpDiscoveryVmIpFinder;
+import org.apache.ignite.testframework.GridStringLogger;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.junit.Test;
+
+/**
+ * Tests that a warning is printed when the IP finder has a long list of addresses (see IGNITE-1025).
+ */
+public class TcpDiscoveryLongAddressListWarnSelfTest extends GridCommonAbstractTest {
+    /** Base port for unavailable addresses. */
+    private static final int UNAVAILABLE_PORT = 49_152;
+
+    /** */
+    private GridStringLogger strLog;
+
+    /** */
+    private int addrCnt;
+
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String igniteInstanceName) throws Exception {
+        IgniteConfiguration cfg = super.getConfiguration(igniteInstanceName);
+
+        List<String> addrs = new ArrayList<>(addrCnt);
+
+        for (int i = 0; i < addrCnt; i++)
+            addrs.add("127.0.0.1:" + (UNAVAILABLE_PORT + i));
+
+        TcpDiscoverySpi spi = new TcpDiscoverySpi()
+            .setIpFinder(new TcpDiscoveryVmIpFinder(true).setAddresses(addrs))
+            .setJoinTimeout(1_000);
+
+        cfg.setDiscoverySpi(spi);
+        cfg.setGridLogger(strLog);
+
+        return cfg;
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testWarnOnLongAddressList() throws Exception {
+        strLog = new GridStringLogger();
+
+        addrCnt = TcpDiscoverySpi.ADDRS_WARN_THRESHOLD + 1;
+
+        startGrid(0);
+
+        String log = strLog.toString();
+
+        assertTrue("Warning must be printed to log: " + log,
+            log.contains("Long list of addresses resolved from IP finder"));
+
+        stopAllGrids();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testNoWarnOnShortAddressList() throws Exception {
+        strLog = new GridStringLogger();
+
+        addrCnt = 3;
+
+        startGrid(0);
+
+        String log = strLog.toString();
+
+        assertFalse("Warning must not be printed to log: " + log,
+            log.contains("Long list of addresses resolved from IP finder"));
+
+        stopAllGrids();
+    }
+}