/**
 * 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.hadoop.crypto.key.kms;

import static org.apache.hadoop.crypto.key.KeyProviderCryptoExtension.EncryptedKeyVersion;
import static org.apache.hadoop.test.LambdaTestUtils.intercept;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.verify;

import java.io.IOException;
import java.net.ConnectException;
import java.net.NoRouteToHostException;
import java.net.SocketTimeoutException;
import java.net.URI;
import java.net.UnknownHostException;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.List;

import javax.net.ssl.SSLHandshakeException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.crypto.key.KeyProvider;
import org.apache.hadoop.crypto.key.KeyProvider.Options;
import org.apache.hadoop.crypto.key.KeyProviderCryptoExtension;
import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
import org.apache.hadoop.net.ConnectTimeoutException;
import org.apache.hadoop.security.AccessControlException;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.security.authentication.client.AuthenticationException;
import org.apache.hadoop.security.authorize.AuthorizationException;
import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.Timeout;
import org.mockito.Mockito;

import com.google.common.collect.Sets;

public class TestLoadBalancingKMSClientProvider {

  @Rule
  public Timeout testTimeout = new Timeout(30 * 1000);

  @BeforeClass
  public static void setup() throws IOException {
    SecurityUtil.setTokenServiceUseIp(false);
  }

  @Test
  public void testCreation() throws Exception {
    Configuration conf = new Configuration();
    KeyProvider kp = new KMSClientProvider.Factory().createProvider(new URI(
        "kms://http@host1:9600/kms/foo"), conf);
    assertTrue(kp instanceof LoadBalancingKMSClientProvider);
    KMSClientProvider[] providers =
        ((LoadBalancingKMSClientProvider) kp).getProviders();
    assertEquals(1, providers.length);
    assertEquals(Sets.newHashSet("http://host1:9600/kms/foo/v1/"),
        Sets.newHashSet(providers[0].getKMSUrl()));

    kp = new KMSClientProvider.Factory().createProvider(new URI(
        "kms://http@host1;host2;host3:9600/kms/foo"), conf);
    assertTrue(kp instanceof LoadBalancingKMSClientProvider);
    providers =
        ((LoadBalancingKMSClientProvider) kp).getProviders();
    assertEquals(3, providers.length);
    assertEquals(Sets.newHashSet("http://host1:9600/kms/foo/v1/",
        "http://host2:9600/kms/foo/v1/",
        "http://host3:9600/kms/foo/v1/"),
        Sets.newHashSet(providers[0].getKMSUrl(),
            providers[1].getKMSUrl(),
            providers[2].getKMSUrl()));

    kp = new KMSClientProvider.Factory().createProvider(new URI(
        "kms://http@host1;host2;host3:9600/kms/foo"), conf);
    assertTrue(kp instanceof LoadBalancingKMSClientProvider);
    providers =
        ((LoadBalancingKMSClientProvider) kp).getProviders();
    assertEquals(3, providers.length);
    assertEquals(Sets.newHashSet("http://host1:9600/kms/foo/v1/",
        "http://host2:9600/kms/foo/v1/",
        "http://host3:9600/kms/foo/v1/"),
        Sets.newHashSet(providers[0].getKMSUrl(),
            providers[1].getKMSUrl(),
            providers[2].getKMSUrl()));
  }

  @Test
  public void testLoadBalancing() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("p1", "v1", new byte[0]));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("p2", "v2", new byte[0]));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("p3", "v3", new byte[0]));
    KeyProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] { p1, p2, p3 }, 0, conf);
    assertEquals("p1", kp.createKey("test1", new Options(conf)).getName());
    assertEquals("p2", kp.createKey("test2", new Options(conf)).getName());
    assertEquals("p3", kp.createKey("test3", new Options(conf)).getName());
    assertEquals("p1", kp.createKey("test4", new Options(conf)).getName());
  }

  @Test
  public void testLoadBalancingWithFailure() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("p1", "v1", new byte[0]));
    when(p1.getKMSUrl()).thenReturn("p1");
    // This should not be retried
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new NoSuchAlgorithmException("p2"));
    when(p2.getKMSUrl()).thenReturn("p2");
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("p3", "v3", new byte[0]));
    when(p3.getKMSUrl()).thenReturn("p3");
    // This should be retried
    KMSClientProvider p4 = mock(KMSClientProvider.class);
    when(p4.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p4"));
    when(p4.getKMSUrl()).thenReturn("p4");
    KeyProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] { p1, p2, p3, p4 }, 0, conf);

    assertEquals("p1", kp.createKey("test4", new Options(conf)).getName());
    // Exceptions other than IOExceptions will not be retried
    try {
      kp.createKey("test1", new Options(conf)).getName();
      fail("Should fail since its not an IOException");
    } catch (Exception e) {
      assertTrue(e instanceof NoSuchAlgorithmException);
    }
    assertEquals("p3", kp.createKey("test2", new Options(conf)).getName());
    // IOException will trigger retry in next provider
    assertEquals("p1", kp.createKey("test3", new Options(conf)).getName());
  }

  @Test
  public void testLoadBalancingWithAllBadNodes() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p3"));
    KMSClientProvider p4 = mock(KMSClientProvider.class);
    when(p4.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p4"));
    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    when(p4.getKMSUrl()).thenReturn("p4");
    KeyProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] { p1, p2, p3, p4 }, 0, conf);
    try {
      kp.createKey("test3", new Options(conf)).getName();
      fail("Should fail since all providers threw an IOException");
    } catch (Exception e) {
      assertTrue(e instanceof IOException);
    }
  }

  // copied from HttpExceptionUtils:

  // trick, riding on generics to throw an undeclared exception

  private static void throwEx(Throwable ex) {
    TestLoadBalancingKMSClientProvider.<RuntimeException>throwException(ex);
  }

  @SuppressWarnings("unchecked")
  private static <E extends Throwable> void throwException(Throwable ex)
      throws E {
    throw (E) ex;
  }

  private class MyKMSClientProvider extends KMSClientProvider {
    public MyKMSClientProvider(URI uri, Configuration conf) throws IOException {
      super(uri, conf);
    }

    @Override
    public EncryptedKeyVersion generateEncryptedKey(
        final String encryptionKeyName)
        throws IOException, GeneralSecurityException {
      throwEx(new AuthenticationException("bar"));
      return null;
    }

    @Override
    public KeyVersion decryptEncryptedKey(
        final EncryptedKeyVersion encryptedKeyVersion) throws IOException,
        GeneralSecurityException {
      throwEx(new AuthenticationException("bar"));
      return null;
    }

    @Override
    public KeyVersion createKey(final String name, final Options options)
        throws NoSuchAlgorithmException, IOException {
      throwEx(new AuthenticationException("bar"));
      return null;
    }

    @Override
    public KeyVersion rollNewVersion(final String name)
        throws NoSuchAlgorithmException, IOException {
      throwEx(new AuthenticationException("bar"));
      return null;
    }
  }

  @Test
  public void testClassCastException() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = new MyKMSClientProvider(
        new URI("kms://http@host1:9600/kms/foo"), conf);
    LoadBalancingKMSClientProvider kp =   new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1}, 0, conf);
    try {
      kp.generateEncryptedKey("foo");
    } catch (IOException ioe) {
      assertTrue(ioe.getCause().getClass().getName().contains(
          "AuthenticationException"));
    }

    try {
      final KeyProviderCryptoExtension.EncryptedKeyVersion
          encryptedKeyVersion =
          mock(KeyProviderCryptoExtension.EncryptedKeyVersion.class);
      kp.decryptEncryptedKey(encryptedKeyVersion);
    } catch (IOException ioe) {
      assertTrue(ioe.getCause().getClass().getName().contains(
          "AuthenticationException"));
    }

    try {
      final KeyProvider.Options options = KeyProvider.options(conf);
      kp.createKey("foo", options);
    } catch (IOException ioe) {
      assertTrue(ioe.getCause().getClass().getName().contains(
          "AuthenticationException"));
    }

    try {
      kp.rollNewVersion("foo");
    } catch (IOException ioe) {
      assertTrue(ioe.getCause().getClass().getName().contains(
          "AuthenticationException"));
    }
  }

  /**
   * tests {@link LoadBalancingKMSClientProvider#warmUpEncryptedKeys(String...)}
   * error handling in case when all the providers throws {@link IOException}.
   * @throws Exception
   */
  @Test
  public void testWarmUpEncryptedKeysWhenAllProvidersFail() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    String keyName = "key1";
    Mockito.doThrow(new IOException(new AuthorizationException("p1"))).when(p1)
        .warmUpEncryptedKeys(Mockito.anyString());
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    Mockito.doThrow(new IOException(new AuthorizationException("p2"))).when(p2)
        .warmUpEncryptedKeys(Mockito.anyString());

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.warmUpEncryptedKeys(keyName);
      fail("Should fail since both providers threw IOException");
    } catch (Exception e) {
      assertTrue(e.getCause() instanceof IOException);
    }
    Mockito.verify(p1, Mockito.times(1)).warmUpEncryptedKeys(keyName);
    Mockito.verify(p2, Mockito.times(1)).warmUpEncryptedKeys(keyName);
  }

  /**
   * tests {@link LoadBalancingKMSClientProvider#warmUpEncryptedKeys(String...)}
   * error handling in case atleast one provider succeeds.
   * @throws Exception
   */
  @Test
  public void testWarmUpEncryptedKeysWhenOneProviderSucceeds()
      throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    String keyName = "key1";
    Mockito.doThrow(new IOException(new AuthorizationException("p1"))).when(p1)
        .warmUpEncryptedKeys(Mockito.anyString());
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    Mockito.doNothing().when(p2)
        .warmUpEncryptedKeys(Mockito.anyString());

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.warmUpEncryptedKeys(keyName);
    } catch (Exception e) {
      fail("Should not throw Exception since p2 doesn't throw Exception");
    }
    Mockito.verify(p1, Mockito.times(1)).warmUpEncryptedKeys(keyName);
    Mockito.verify(p2, Mockito.times(1)).warmUpEncryptedKeys(keyName);
  }

  /**
   * Tests whether retryPolicy fails immediately on non-idempotent operations,
   * after trying each provider once,
   * on encountering IOException which is not SocketException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesNonIdempotentOpWithIOExceptionFailsImmediately()
      throws Exception {
    Configuration conf = new Configuration();
    final String keyName = "test";
    // Setting total failover attempts to .
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 10);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p3"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2, p3}, 0, conf);
    try {
      kp.createKey(keyName, new Options(conf));
      fail("Should fail since all providers threw an IOException");
    } catch (Exception e) {
      assertTrue(e instanceof IOException);
    }
    verify(kp.getProviders()[0], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
    verify(kp.getProviders()[1], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
    verify(kp.getProviders()[2], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
  }

  /**
   * Tests whether retryPolicy retries on idempotent operations
   * when encountering IOException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesIdempotentOpWithIOExceptionSucceedsSecondTime()
      throws Exception {
    Configuration conf = new Configuration();
    final String keyName = "test";
    final KeyProvider.KeyVersion keyVersion
        = new KMSClientProvider.KMSKeyVersion(keyName, "v1",
        new byte[0]);
    // Setting total failover attempts to .
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 10);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.getCurrentKey(Mockito.anyString()))
        .thenThrow(new IOException("p1"))
        .thenReturn(keyVersion);
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.getCurrentKey(Mockito.anyString()))
        .thenThrow(new IOException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.getCurrentKey(Mockito.anyString()))
        .thenThrow(new IOException("p3"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2, p3}, 0, conf);

    KeyProvider.KeyVersion result = kp.getCurrentKey(keyName);

    assertEquals(keyVersion, result);
    verify(kp.getProviders()[0], Mockito.times(2))
        .getCurrentKey(Mockito.eq(keyName));
    verify(kp.getProviders()[1], Mockito.times(1))
        .getCurrentKey(Mockito.eq(keyName));
    verify(kp.getProviders()[2], Mockito.times(1))
        .getCurrentKey(Mockito.eq(keyName));
  }

  /**
   * Tests that client doesn't retry once it encounters AccessControlException
   * from first provider.
   * This assumes all the kms servers are configured with identical access to
   * keys.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithAccessControlException() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new AccessControlException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p3"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2, p3}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
      fail("Should fail because provider p1 threw an AccessControlException");
    } catch (Exception e) {
      assertTrue(e instanceof AccessControlException);
    }
    verify(p1, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.never()).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p3, Mockito.never()).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests that client doesn't retry once it encounters RunTimeException
   * from first provider.
   * This assumes all the kms servers are configured with identical access to
   * keys.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithRuntimeException() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new RuntimeException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
      fail("Should fail since provider p1 threw RuntimeException");
    } catch (Exception e) {
      assertTrue(e instanceof RuntimeException);
    }
    verify(p1, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.never()).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests the client retries until it finds a good provider.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithTimeoutsException() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 4);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new UnknownHostException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new NoRouteToHostException("p3"));
    KMSClientProvider p4 = mock(KMSClientProvider.class);
    when(p4.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenReturn(
            new KMSClientProvider.KMSKeyVersion("test3", "v1", new byte[0]));
    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    when(p4.getKMSUrl()).thenReturn("p4");
    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2, p3, p4}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
    } catch (Exception e) {
      fail("Provider p4 should have answered the request.");
    }
    verify(p1, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p3, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p4, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests the operation succeeds second time after ConnectTimeoutException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesSucceedsSecondTime() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p1"))
        .thenReturn(new KMSClientProvider.KMSKeyVersion("test3", "v1",
                new byte[0]));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
    } catch (Exception e) {
      fail("Provider p1 should have answered the request second time.");
    }
    verify(p1, Mockito.times(2)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests whether retryPolicy retries specified number of times.
   * @throws Exception
   */
  @Test
  public void testClientRetriesSpecifiedNumberOfTimes() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 10);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
      fail("Should fail");
    } catch (Exception e) {
     assert (e instanceof ConnectTimeoutException);
    }
    verify(p1, Mockito.times(6)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.times(5)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests whether retryPolicy retries number of times equals to number of
   * providers if conf kms.client.failover.max.attempts is not set.
   * @throws Exception
   */
  @Test
  public void testClientRetriesIfMaxAttemptsNotSet() throws Exception {
    Configuration conf = new Configuration();
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectTimeoutException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
      fail("Should fail");
    } catch (Exception e) {
     assert (e instanceof ConnectTimeoutException);
    }
    verify(p1, Mockito.times(2)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests that client reties each provider once, when it encounters
   * AuthenticationException wrapped in an IOException from first provider.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithAuthenticationExceptionWrappedinIOException()
      throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException(new AuthenticationException("p1")));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new IOException(new AuthenticationException("p1")));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);
    try {
      kp.createKey("test3", new Options(conf));
      fail("Should fail since provider p1 threw AuthenticationException");
    } catch (Exception e) {
      assertTrue(e.getCause() instanceof AuthenticationException);
    }
    verify(p1, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq("test3"),
            Mockito.any(Options.class));
  }

  /**
   * Tests the operation succeeds second time after SSLHandshakeException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithSSLHandshakeExceptionSucceedsSecondTime()
      throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    final String keyName = "test";
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new SSLHandshakeException("p1"))
        .thenReturn(new KMSClientProvider.KMSKeyVersion(keyName, "v1",
            new byte[0]));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);

    kp.createKey(keyName, new Options(conf));
    verify(p1, Mockito.times(2)).createKey(Mockito.eq(keyName),
        Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq(keyName),
        Mockito.any(Options.class));
  }

  /**
   * Tests the operation fails at every attempt after SSLHandshakeException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesWithSSLHandshakeExceptionFailsAtEveryAttempt()
      throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 2);
    final String keyName = "test";
    final String exceptionMessage = "p1 exception message";
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    Exception originalSslEx = new SSLHandshakeException(exceptionMessage);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(originalSslEx);
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new ConnectException("p2 exception message"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);

    Exception interceptedEx = intercept(ConnectException.class,
        "SSLHandshakeException: " + exceptionMessage,
        ()-> kp.createKey(keyName, new Options(conf)));
    assertEquals(originalSslEx, interceptedEx.getCause());

    verify(p1, Mockito.times(2)).createKey(Mockito.eq(keyName),
        Mockito.any(Options.class));
    verify(p2, Mockito.times(1)).createKey(Mockito.eq(keyName),
        Mockito.any(Options.class));
  }

  /**
   * Tests that if an idempotent operation succeeds second time after
   * SocketTimeoutException, then the operation is successful.
   * @throws Exception
   */
  @Test
  public void testClientRetriesIdempotentOpWithSocketTimeoutExceptionSucceeds()
      throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 3);
    final List<String> keys = Arrays.asList("testKey");
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.getKeys())
        .thenThrow(new SocketTimeoutException("p1"))
        .thenReturn(keys);
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.getKeys()).thenThrow(new SocketTimeoutException("p2"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);

    List<String> result = kp.getKeys();
    assertEquals(keys, result);
    verify(p1, Mockito.times(2)).getKeys();
    verify(p2, Mockito.times(1)).getKeys();
  }

  /**
   * Tests that if a non idempotent operation fails at every attempt
   * after SocketTimeoutException, then SocketTimeoutException is thrown.
   * @throws Exception
   */
  @Test
  public void testClientRetriesIdempotentOpWithSocketTimeoutExceptionFails()
      throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 2);
    final String keyName = "test";
    final String exceptionMessage = "p1 exception message";
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    Exception originalEx = new SocketTimeoutException(exceptionMessage);
    when(p1.getKeyVersions(Mockito.anyString()))
        .thenThrow(originalEx);
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.getKeyVersions(Mockito.anyString()))
        .thenThrow(new SocketTimeoutException("p2 exception message"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");

    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2}, 0, conf);

    Exception interceptedEx = intercept(SocketTimeoutException.class,
        "SocketTimeoutException: " + exceptionMessage,
        ()-> kp.getKeyVersions(keyName));
    assertEquals(originalEx, interceptedEx);

    verify(p1, Mockito.times(2))
        .getKeyVersions(Mockito.eq(keyName));
    verify(p2, Mockito.times(1))
        .getKeyVersions(Mockito.eq(keyName));
  }

  /**
   * Tests whether retryPolicy fails immediately on non-idempotent operations,
   * after trying each provider once, on encountering SocketTimeoutException.
   * @throws Exception
   */
  @Test
  public void testClientRetriesNonIdempotentOpWithSocketTimeoutExceptionFails()
      throws Exception {
    Configuration conf = new Configuration();
    final String keyName = "test";
    // Setting total failover attempts to .
    conf.setInt(
        CommonConfigurationKeysPublic.KMS_CLIENT_FAILOVER_MAX_RETRIES_KEY, 10);
    KMSClientProvider p1 = mock(KMSClientProvider.class);
    when(p1.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new SocketTimeoutException("p1"));
    KMSClientProvider p2 = mock(KMSClientProvider.class);
    when(p2.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new SocketTimeoutException("p2"));
    KMSClientProvider p3 = mock(KMSClientProvider.class);
    when(p3.createKey(Mockito.anyString(), Mockito.any(Options.class)))
        .thenThrow(new SocketTimeoutException("p3"));

    when(p1.getKMSUrl()).thenReturn("p1");
    when(p2.getKMSUrl()).thenReturn("p2");
    when(p3.getKMSUrl()).thenReturn("p3");
    LoadBalancingKMSClientProvider kp = new LoadBalancingKMSClientProvider(
        new KMSClientProvider[] {p1, p2, p3}, 0, conf);
    try {
      kp.createKey(keyName, new Options(conf));
      fail("Should fail since all providers threw a SocketTimeoutException");
    } catch (Exception e) {
      assertTrue(e instanceof SocketTimeoutException);
    }
    verify(kp.getProviders()[0], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
    verify(kp.getProviders()[1], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
    verify(kp.getProviders()[2], Mockito.times(1))
        .createKey(Mockito.eq(keyName), Mockito.any(Options.class));
  }

  @Test
  public void testTokenServiceCreationWithLegacyFormat() throws Exception {
    Configuration conf = new Configuration();
    // Create keyprovider with old token format (ip:port)
    conf.set(CommonConfigurationKeysPublic.HADOOP_SECURITY_KEY_PROVIDER_PATH,
        "kms:/something");
    String authority = "host1:9600";
    URI kmsUri = URI.create("kms://http@" + authority + "/kms/foo");
    KeyProvider kp =
        new KMSClientProvider.Factory().createProvider(kmsUri, conf);
    assertTrue(kp instanceof LoadBalancingKMSClientProvider);
    LoadBalancingKMSClientProvider lbkp = (LoadBalancingKMSClientProvider) kp;
    assertEquals(1, lbkp.getProviders().length);
    assertEquals(authority, lbkp.getCanonicalServiceName());
    for (KMSClientProvider provider : lbkp.getProviders()) {
      assertEquals(authority, provider.getCanonicalServiceName());
    }
  }

  @Test
  public void testTokenServiceCreationWithUriFormat() throws Exception {
    final Configuration conf = new Configuration();
    final URI kmsUri = URI.create("kms://http@host1;host2;host3:9600/kms/foo");
    final KeyProvider kp =
        new KMSClientProvider.Factory().createProvider(kmsUri, conf);
    assertTrue(kp instanceof LoadBalancingKMSClientProvider);
    final LoadBalancingKMSClientProvider lbkp =
        (LoadBalancingKMSClientProvider) kp;
    assertEquals(kmsUri.toString(), lbkp.getCanonicalServiceName());
    KMSClientProvider[] providers = lbkp.getProviders();
    assertEquals(3, providers.length);
    for (int i = 0; i < providers.length; i++) {
      assertEquals(URI.create(providers[i].getKMSUrl()).getAuthority(),
          providers[i].getCanonicalServiceName());
      assertNotEquals(kmsUri, providers[i].getCanonicalServiceName());
    }
  }
}