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*
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package com.salesforce.kafka.test;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
class ZookeeperTestServerTest {
/**
* Test start() starts the service and gracefully handles being called multiple times.
*/
@Test
void testStart() throws Exception {
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service.
zookeeperTestServer.start();
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(zookeeperTestServer.getConnectString());
// Call start again
zookeeperTestServer.start();
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(zookeeperTestServer.getConnectString());
}
}
/**
* Test restart() starts the service gracefully if not started.
*/
@Test
void testRestartCold() throws Exception {
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service by calling restart()
zookeeperTestServer.restart();
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(zookeeperTestServer.getConnectString());
}
}
/**
* Test restart() restarts the service if already started.
*/
@Test
void testRestart() throws Exception {
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service
zookeeperTestServer.start();
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(zookeeperTestServer.getConnectString());
// Call restart
zookeeperTestServer.restart();
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(zookeeperTestServer.getConnectString());
}
}
/**
* Test restarting preserves data stored.
*/
@Test
void testRestartPreservesData() throws Exception {
final String pathStr = "/preservedData" + System.currentTimeMillis();
final String dataStr = "MySpecialData" + System.currentTimeMillis();
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service
zookeeperTestServer.start();
ZooKeeper zkClient = null;
try {
// Create client
zkClient = createZkClient(zookeeperTestServer.getConnectString());
// Write data
writeZkString(zkClient, pathStr, dataStr);
} finally {
// Close client.
if (zkClient != null) {
zkClient.close();
}
}
// Call restart on server.
zookeeperTestServer.restart();
// Attempt to read original data out.
try {
// Create client
zkClient = createZkClient(zookeeperTestServer.getConnectString());
// Write data
final String result = readZkString(zkClient, pathStr);
Assertions.assertEquals(dataStr, result);
} finally {
// Close client.
if (zkClient != null) {
zkClient.close();
}
}
}
}
/**
* Test calling stop() then start() preserves data stored.
*/
@Test
void testStopAndStartPreservesData() throws Exception {
final String pathStr = "/preservedStopAndStartData" + System.currentTimeMillis();
final String dataStr = "MyOtherSpecialData" + System.currentTimeMillis();
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service
zookeeperTestServer.start();
ZooKeeper zkClient = null;
try {
// Create client
zkClient = createZkClient(zookeeperTestServer.getConnectString());
// Write data
writeZkString(zkClient, pathStr, dataStr);
} finally {
// Close client.
if (zkClient != null) {
zkClient.close();
}
}
// Call stop on server.
zookeeperTestServer.stop();
Thread.sleep(2000L);
// Followed by start
zookeeperTestServer.start();
// Attempt to read original data out.
try {
// Create client
zkClient = createZkClient(zookeeperTestServer.getConnectString());
// Write data
final String result = readZkString(zkClient, pathStr);
Assertions.assertEquals(dataStr, result);
} finally {
// Close client.
if (zkClient != null) {
zkClient.close();
}
}
}
}
/**
* Test calling getConnectString() before calling start on the service.
* It's expected to throw an IllegalStateException.
*/
@Test
void testGetConnectStringBeforeStartingService() {
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
Assertions.assertThrows(IllegalStateException.class, zookeeperTestServer::getConnectString);
}
}
/**
* Test calling getConnectString() after calling start on the service.
*/
@Test
void testGetConnectString() throws Exception {
// Create instance.
try (final ZookeeperTestServer zookeeperTestServer = new ZookeeperTestServer()) {
// Start service.
zookeeperTestServer.start();
// Ask for the connect String
final String connectString = zookeeperTestServer.getConnectString();
Assertions.assertNotNull(connectString);
// Validate the zookeeper server appears to be functioning.
testZookeeperConnection(connectString);
}
}
/**
* Attempts to validate a Zookeeper server by the following criteria.
* - connecting
* - create a new node
* - reading that node
* - closing connection
*
* @param zkConnectString Zookeeper host.
*/
private void testZookeeperConnection(final String zkConnectString) throws Exception {
final String pathStr = "/zkTest" + System.currentTimeMillis();
final String dataStr = "zkData" + System.currentTimeMillis();
// Attempt to connect using a zookeeper client.
ZooKeeper zkClient = null;
try {
zkClient = createZkClient(zkConnectString);
// Create a new node storing dataBytes.
writeZkString(zkClient, pathStr, dataStr);
// Read back out of Zookeeper
final String resultStr = readZkString(zkClient, pathStr);
// Validate we got what we expected.
Assertions.assertEquals(dataStr, resultStr);
} finally {
if (zkClient != null) {
zkClient.close();
}
}
}
/**
* Helper method to create a zookeeper client.
*/
private ZooKeeper createZkClient(final String zkConnectString) throws IOException, InterruptedException {
// Blocks until connected, or 5 sec timeout expires.
final CountDownLatch connectionLatch = new CountDownLatch(1);
// Attempt to connect using a zookeeper client.
final ZooKeeper zkClient = new ZooKeeper(zkConnectString, 1000, event -> {
if (event.getState() == Watcher.Event.KeeperState.SyncConnected) {
connectionLatch.countDown();
}
});
// Wait for connection.
connectionLatch.await(5, TimeUnit.SECONDS);
return zkClient;
}
/**
* Helper method to write data to zookeeper.
*/
private void writeZkString(
final ZooKeeper zkClient,
final String path,
final String data
) throws KeeperException, InterruptedException {
// Create a new node storing dataBytes.
zkClient.create(path, data.getBytes(StandardCharsets.UTF_8), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}
/**
* Helper method to read data from zookeeper.
*/
private String readZkString(final ZooKeeper zkClient, final String path) throws KeeperException, InterruptedException {
return new String(
zkClient.getData(path, null, null),
StandardCharsets.UTF_8
);
}
}
