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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.config;
import com.yahoo.config.subscription.ConfigSourceSet;
import org.junit.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
/**
* Tests for the JRTConnectionPool class.
*
* @author Gunnar Gauslaa Bergem
* @author hmusum
*/
public class JRTConnectionPoolTest {
private static final ConfigSourceSet sources = new ConfigSourceSet(List.of("host0", "host1", "host2"));
@Test
public void test_random_selection_of_source() {
JRTConnectionPool sourcePool = new JRTConnectionPool(sources);
assertEquals("host0,host1,host2",
sourcePool.getSources().stream().map(JRTConnection::getAddress).collect(Collectors.joining(",")));
Map<String, Integer> sourceOccurrences = new HashMap<>();
for (int i = 0; i < 1000; i++) {
String address = sourcePool.switchConnection().getAddress();
if (sourceOccurrences.containsKey(address)) {
sourceOccurrences.put(address, sourceOccurrences.get(address) + 1);
} else {
sourceOccurrences.put(address, 1);
}
}
for (int i = 0; i < sourcePool.getSize(); i++) {
assertTrue(sourceOccurrences.get(sourcePool.getSources().get(i).getAddress()) > 200);
}
}
/**
* Tests that when there are two sources and several clients
* the sources will be chosen with about the same probability.
*/
@Test
public void testManySources() {
Map<String, Integer> timesUsed = new LinkedHashMap<>();
ConfigSourceSet twoSources = new ConfigSourceSet(List.of("host0", "host1"));
JRTConnectionPool sourcePool = new JRTConnectionPool(twoSources);
int count = 1000;
for (int i = 0; i < count; i++) {
String address = sourcePool.switchConnection().getAddress();
if (timesUsed.containsKey(address)) {
int times = timesUsed.get(address);
timesUsed.put(address, times + 1);
} else {
timesUsed.put(address, 1);
}
}
assertConnectionDistributionIsFair(timesUsed);
sourcePool.close();
}
// Tests that the number of times each connection is used is close to equal
private void assertConnectionDistributionIsFair(Map<String, Integer> connectionsUsedPerHost) {
double deviationDueToRandomSourceSelection = 0.15;
final int size = 1000;
int minHostCount = (int) (size/2 * (1 - deviationDueToRandomSourceSelection));
int maxHostCount = (int) (size/2 * (1 + deviationDueToRandomSourceSelection));
for (Map.Entry<String, Integer> entry : connectionsUsedPerHost.entrySet()) {
Integer timesUsed = entry.getValue();
assertTrue("Host 0 used " + timesUsed + " times, expected to be < " + maxHostCount, timesUsed < maxHostCount);
assertTrue("Host 0 used " + timesUsed + " times, expected to be > " + minHostCount, timesUsed > minHostCount);
}
}
/**
* Tests that updating config sources works.
*/
@Test
public void updateSources() {
ConfigSourceSet twoSources = new ConfigSourceSet(List.of("host0", "host1"));
JRTConnectionPool sourcePool = new JRTConnectionPool(twoSources);
ConfigSourceSet sourcesBefore = sourcePool.getSourceSet();
// Update to the same set, should be equal
sourcePool.updateSources(twoSources);
assertEquals(sourcePool.getSourceSet(), sourcesBefore);
// Update to new set
List<String> newSources = new ArrayList<>();
newSources.add("host2");
newSources.add("host3");
sourcePool.updateSources(newSources);
ConfigSourceSet newSourceSet = sourcePool.getSourceSet();
assertNotNull(newSourceSet);
assertEquals(2, newSourceSet.getSources().size());
assertNotEquals(sourcesBefore, newSourceSet);
assertTrue(newSourceSet.getSources().contains("host2"));
assertTrue(newSourceSet.getSources().contains("host3"));
// Update to new set with just one host
List<String> newSources2 = new ArrayList<>();
newSources2.add("host4");
sourcePool.updateSources(newSources2);
ConfigSourceSet newSourceSet2 = sourcePool.getSourceSet();
assertNotNull(newSourceSet2);
assertEquals(1, newSourceSet2.getSources().size());
assertNotEquals(newSourceSet, newSourceSet2);
assertTrue(newSourceSet2.getSources().contains("host4"));
sourcePool.close();
}
@Test
public void testFailingSources() {
ConfigSourceSet sources = new ConfigSourceSet(List.of("host0", "host1"));
JRTConnectionPool connectionPool = new JRTConnectionPool(sources);
Connection firstConnection = connectionPool.getCurrent();
// Should change connection, not getting first connection as new
JRTConnection secondConnection = failAndGetNewConnection(connectionPool, firstConnection);
assertNotEquals(firstConnection, secondConnection);
// Should change connection, not getting second connection as new
JRTConnection thirdConnection = failAndGetNewConnection(connectionPool, secondConnection);
// Fail a few more times with old connection, as will happen when there are multiple subscribers
// Connection should not change
assertEquals(thirdConnection, failAndGetNewConnection(connectionPool, secondConnection));
assertEquals(thirdConnection, failAndGetNewConnection(connectionPool, secondConnection));
assertEquals(thirdConnection, failAndGetNewConnection(connectionPool, secondConnection));
assertNotEquals(secondConnection, thirdConnection);
// Should change connection, not getting third connection as new
JRTConnection currentConnection = failAndGetNewConnection(connectionPool, thirdConnection);
assertNotEquals(thirdConnection, currentConnection);
// Should change connection, not getting current connection as new
JRTConnection currentConnection2 = failAndGetNewConnection(connectionPool, currentConnection);
assertNotEquals(currentConnection, currentConnection2);
connectionPool.close();
}
private JRTConnection failAndGetNewConnection(JRTConnectionPool connectionPool, Connection failingConnection) {
connectionPool.switchConnection(failingConnection);
return connectionPool.getCurrent();
}
}
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