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package com.google.api.gax.grpc;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertEquals;

import com.google.api.core.ApiFunction;
import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.Builder;
import com.google.api.gax.rpc.HeaderProvider;
import com.google.api.gax.rpc.TransportChannelProvider;
import com.google.api.gax.rpc.mtls.AbstractMtlsTransportChannelTest;
import com.google.api.gax.rpc.mtls.MtlsProvider;
import com.google.auth.oauth2.CloudShellCredentials;
import com.google.auth.oauth2.ComputeEngineCredentials;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.alts.ComputeEngineChannelBuilder;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import javax.annotation.Nullable;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.mockito.ArgumentCaptor;
import org.mockito.Mockito;
import org.threeten.bp.Duration;

@RunWith(JUnit4.class)
public class InstantiatingGrpcChannelProviderTest extends AbstractMtlsTransportChannelTest {

  @Test
  public void testEndpoint() {
    String endpoint = "localhost:8080";
    InstantiatingGrpcChannelProvider.Builder builder =
        InstantiatingGrpcChannelProvider.newBuilder();
    builder.setEndpoint(endpoint);
    assertEquals(builder.getEndpoint(), endpoint);

    InstantiatingGrpcChannelProvider provider = builder.build();
    assertEquals(provider.getEndpoint(), endpoint);
  }

  @Test(expected = IllegalArgumentException.class)
  public void testEndpointNoPort() {
    InstantiatingGrpcChannelProvider.newBuilder().setEndpoint("localhost");
  }

  @Test(expected = IllegalArgumentException.class)
  public void testEndpointBadPort() {
    InstantiatingGrpcChannelProvider.newBuilder().setEndpoint("localhost:abcd");
  }

  @Test
  public void testKeepAlive() {
    Duration keepaliveTime = Duration.ofSeconds(1);
    Duration keepaliveTimeout = Duration.ofSeconds(2);
    boolean keepaliveWithoutCalls = true;

    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setKeepAliveTime(keepaliveTime)
            .setKeepAliveTimeout(keepaliveTimeout)
            .setKeepAliveWithoutCalls(keepaliveWithoutCalls)
            .build();

    assertEquals(provider.getKeepAliveTime(), keepaliveTime);
    assertEquals(provider.getKeepAliveTimeout(), keepaliveTimeout);
    assertEquals(provider.getKeepAliveWithoutCalls(), keepaliveWithoutCalls);
  }

  @Test
  public void testMaxInboundMetadataSize() {
    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder().setMaxInboundMetadataSize(4096).build();
    assertThat(provider.getMaxInboundMetadataSize()).isEqualTo(4096);
  }

  @Test
  public void testCpuPoolSize() {
    // happy path
    Builder builder = InstantiatingGrpcChannelProvider.newBuilder().setProcessorCount(2);
    builder.setChannelsPerCpu(2.5);
    assertEquals(5, builder.getPoolSize());

    // User specified max
    builder = builder.setProcessorCount(50);
    builder.setChannelsPerCpu(100, 10);
    assertEquals(10, builder.getPoolSize());

    // Sane default maximum
    builder.setChannelsPerCpu(200);
    assertEquals(100, builder.getPoolSize());
  }

  @Test
  public void testWithPoolSize() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("localhost:8080");
    assertThat(provider.acceptsPoolSize()).isTrue();

    // Make sure we can create channels OK.
    provider.getTransportChannel().shutdownNow();

    provider = provider.withPoolSize(2);
    provider.getTransportChannel().shutdownNow();
  }

  @Test
  public void testToBuilder() {
    Duration keepaliveTime = Duration.ofSeconds(1);
    Duration keepaliveTimeout = Duration.ofSeconds(2);
    ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
        builder -> {
          throw new UnsupportedOperationException();
        };
    Map<String, ?> directPathServiceConfig = ImmutableMap.of("loadbalancingConfig", "grpclb");

    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setProcessorCount(2)
            .setEndpoint("fake.endpoint:443")
            .setMaxInboundMessageSize(12345678)
            .setMaxInboundMetadataSize(4096)
            .setKeepAliveTime(keepaliveTime)
            .setKeepAliveTimeout(keepaliveTimeout)
            .setKeepAliveWithoutCalls(true)
            .setChannelConfigurator(channelConfigurator)
            .setChannelsPerCpu(2.5)
            .setDirectPathServiceConfig(directPathServiceConfig)
            .build();

    InstantiatingGrpcChannelProvider.Builder builder = provider.toBuilder();

    assertThat(builder.getEndpoint()).isEqualTo("fake.endpoint:443");
    assertThat(builder.getMaxInboundMessageSize()).isEqualTo(12345678);
    assertThat(builder.getMaxInboundMetadataSize()).isEqualTo(4096);
    assertThat(builder.getKeepAliveTime()).isEqualTo(keepaliveTime);
    assertThat(builder.getKeepAliveTimeout()).isEqualTo(keepaliveTimeout);
    assertThat(builder.getChannelConfigurator()).isEqualTo(channelConfigurator);
    assertThat(builder.getPoolSize()).isEqualTo(5);
    assertThat(builder.build().directPathServiceConfig).isEqualTo(directPathServiceConfig);
  }

  @Test
  public void testWithInterceptors() throws Exception {
    testWithInterceptors(1);
  }

  @Test
  public void testWithInterceptorsAndMultipleChannels() throws Exception {
    testWithInterceptors(5);
  }

  private void testWithInterceptors(int numChannels) throws Exception {
    final GrpcInterceptorProvider interceptorProvider = Mockito.mock(GrpcInterceptorProvider.class);

    InstantiatingGrpcChannelProvider channelProvider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setEndpoint("localhost:8080")
            .setPoolSize(numChannels)
            .setHeaderProvider(Mockito.mock(HeaderProvider.class))
            .setExecutor(Mockito.mock(Executor.class))
            .setInterceptorProvider(interceptorProvider)
            .build();

    Mockito.verify(interceptorProvider, Mockito.never()).getInterceptors();
    channelProvider.getTransportChannel().shutdownNow();
    Mockito.verify(interceptorProvider, Mockito.times(numChannels)).getInterceptors();
  }

  @Test
  public void testChannelConfigurator() throws IOException {
    final int numChannels = 5;

    // Create a mock configurator that will insert mock channels
    @SuppressWarnings("unchecked")
    ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
        Mockito.mock(ApiFunction.class);

    ArgumentCaptor<ManagedChannelBuilder<?>> channelBuilderCaptor =
        ArgumentCaptor.forClass(ManagedChannelBuilder.class);

    ManagedChannelBuilder<?> swappedBuilder = Mockito.mock(ManagedChannelBuilder.class);
    ManagedChannel fakeChannel = Mockito.mock(ManagedChannel.class);
    Mockito.when(swappedBuilder.build()).thenReturn(fakeChannel);

    Mockito.when(channelConfigurator.apply(channelBuilderCaptor.capture()))
        .thenReturn(swappedBuilder);

    // Invoke the provider
    InstantiatingGrpcChannelProvider.newBuilder()
        .setEndpoint("localhost:8080")
        .setHeaderProvider(Mockito.mock(HeaderProvider.class))
        .setExecutor(Mockito.mock(Executor.class))
        .setChannelConfigurator(channelConfigurator)
        .setPoolSize(numChannels)
        .build()
        .getTransportChannel();

    // Make sure that the provider passed in a configured channel
    assertThat(channelBuilderCaptor.getValue()).isNotNull();
    // And that it was replaced with the mock
    Mockito.verify(swappedBuilder, Mockito.times(numChannels)).build();
  }

  @Test
  public void testWithGCECredentials() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setAttemptDirectPath(true)
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("localhost:8080");

    assertThat(provider.needsCredentials()).isTrue();
    if (InstantiatingGrpcChannelProvider.isOnComputeEngine()) {
      provider = provider.withCredentials(ComputeEngineCredentials.create());
    } else {
      provider = provider.withCredentials(CloudShellCredentials.create(3000));
    }
    assertThat(provider.needsCredentials()).isFalse();

    provider.getTransportChannel().shutdownNow();
  }

  @Test
  public void testDirectPathXdsDisableByDefault() throws IOException {
    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder().setAttemptDirectPath(true).build();

    assertThat(provider.isDirectPathXdsEnabled()).isFalse();
  }

  @Test
  public void testDirectPathXdsEnabled() throws IOException {
    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setAttemptDirectPath(true)
            .setAttemptDirectPathXds()
            .build();

    assertThat(provider.isDirectPathXdsEnabled()).isTrue();
  }

  @Test
  public void testWithNonGCECredentials() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
        channelBuilder -> {
          // Clients with non-GCE credentials will not attempt DirectPath.
          assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isFalse();
          return channelBuilder;
        };

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setAttemptDirectPath(true)
            .setChannelConfigurator(channelConfigurator)
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("localhost:8080");

    assertThat(provider.needsCredentials()).isTrue();
    provider = provider.withCredentials(CloudShellCredentials.create(3000));
    assertThat(provider.needsCredentials()).isFalse();

    provider.getTransportChannel().shutdownNow();
  }

  @Test
  public void testWithDirectPathDisabled() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
        channelBuilder -> {
          // Clients without setting attemptDirectPath flag will not attempt DirectPath
          assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isFalse();
          return channelBuilder;
        };

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setAttemptDirectPath(false)
            .setChannelConfigurator(channelConfigurator)
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("localhost:8080");

    assertThat(provider.needsCredentials()).isTrue();
    provider = provider.withCredentials(ComputeEngineCredentials.create());
    assertThat(provider.needsCredentials()).isFalse();

    provider.getTransportChannel().shutdownNow();
  }

  @Test
  public void testWithNoDirectPathFlagSet() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
        channelBuilder -> {
          // Clients without setting attemptDirectPath flag will not attempt DirectPath
          assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isFalse();
          return channelBuilder;
        };

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setChannelConfigurator(channelConfigurator)
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("localhost:8080");

    assertThat(provider.needsCredentials()).isTrue();
    provider = provider.withCredentials(ComputeEngineCredentials.create());
    assertThat(provider.needsCredentials()).isFalse();

    provider.getTransportChannel().shutdownNow();
  }

  @Test
  public void testWithIPv6Address() throws IOException {
    ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1);
    executor.shutdown();

    TransportChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .build()
            .withExecutor((Executor) executor)
            .withHeaders(Collections.<String, String>emptyMap())
            .withEndpoint("[::1]:8080");
    assertThat(provider.needsEndpoint()).isFalse();

    // Make sure we can create channels OK.
    provider.getTransportChannel().shutdownNow();
  }

  // Test that if ChannelPrimer is provided, it is called during creation
  @Test
  public void testWithPrimeChannel() throws IOException {
    // create channelProvider with different pool sizes to verify ChannelPrimer is called the
    // correct number of times
    for (int poolSize = 1; poolSize < 5; poolSize++) {
      final ChannelPrimer mockChannelPrimer = Mockito.mock(ChannelPrimer.class);

      InstantiatingGrpcChannelProvider provider =
          InstantiatingGrpcChannelProvider.newBuilder()
              .setEndpoint("localhost:8080")
              .setPoolSize(poolSize)
              .setHeaderProvider(Mockito.mock(HeaderProvider.class))
              .setExecutor(Mockito.mock(Executor.class))
              .setChannelPrimer(mockChannelPrimer)
              .build();

      provider.getTransportChannel().shutdownNow();

      // every channel in the pool should call primeChannel during creation.
      Mockito.verify(mockChannelPrimer, Mockito.times(poolSize))
          .primeChannel(Mockito.any(ManagedChannel.class));
    }
  }

  @Test
  public void testWithDefaultDirectPathServiceConfig() {
    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder().build();

    ImmutableMap<String, ?> defaultServiceConfig = provider.directPathServiceConfig;

    List<Map<String, ?>> lbConfigs = getAsObjectList(defaultServiceConfig, "loadBalancingConfig");
    assertThat(lbConfigs).hasSize(1);
    Map<String, ?> lbConfig = lbConfigs.get(0);
    Map<String, ?> grpclb = getAsObject(lbConfig, "grpclb");
    List<Map<String, ?>> childPolicies = getAsObjectList(grpclb, "childPolicy");
    assertThat(childPolicies).hasSize(1);
    Map<String, ?> childPolicy = childPolicies.get(0);
    assertThat(childPolicy.keySet()).containsExactly("pick_first");
  }

  @Nullable
  private static Map<String, ?> getAsObject(Map<String, ?> json, String key) {
    Object mapObject = json.get(key);
    if (mapObject == null) {
      return null;
    }
    return checkObject(mapObject);
  }

  @SuppressWarnings("unchecked")
  private static Map<String, ?> checkObject(Object json) {
    checkArgument(json instanceof Map, "Invalid json object representation: %s", json);
    for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) json).entrySet()) {
      checkArgument(entry.getKey() instanceof String, "Key is not string");
    }
    return (Map<String, ?>) json;
  }

  private static List<Map<String, ?>> getAsObjectList(Map<String, ?> json, String key) {
    Object listObject = json.get(key);
    if (listObject == null) {
      return null;
    }
    return checkListOfObjects(listObject);
  }

  @SuppressWarnings("unchecked")
  private static List<Map<String, ?>> checkListOfObjects(Object listObject) {
    checkArgument(listObject instanceof List, "Passed object is not a list");
    List<Map<String, ?>> list = new ArrayList<>();
    for (Object object : ((List<Object>) listObject)) {
      list.add(checkObject(object));
    }
    return list;
  }

  @Test
  public void testWithCustomDirectPathServiceConfig() {
    ImmutableMap<String, Object> pickFirstStrategy =
        ImmutableMap.<String, Object>of("round_robin", ImmutableMap.of());
    ImmutableMap<String, Object> childPolicy =
        ImmutableMap.<String, Object>of(
            "childPolicy", ImmutableList.of(pickFirstStrategy), "foo", "bar");
    ImmutableMap<String, Object> grpcLbPolicy =
        ImmutableMap.<String, Object>of("grpclb", childPolicy);
    Map<String, Object> passedServiceConfig = new HashMap<>();
    passedServiceConfig.put("loadBalancingConfig", ImmutableList.of(grpcLbPolicy));

    InstantiatingGrpcChannelProvider provider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setDirectPathServiceConfig(passedServiceConfig)
            .build();

    ImmutableMap<String, ?> defaultServiceConfig = provider.directPathServiceConfig;
    assertThat(defaultServiceConfig).isEqualTo(passedServiceConfig);
  }

  @Override
  protected Object getMtlsObjectFromTransportChannel(MtlsProvider provider)
      throws IOException, GeneralSecurityException {
    InstantiatingGrpcChannelProvider channelProvider =
        InstantiatingGrpcChannelProvider.newBuilder()
            .setEndpoint("localhost:8080")
            .setMtlsProvider(provider)
            .setHeaderProvider(Mockito.mock(HeaderProvider.class))
            .setExecutor(Mockito.mock(Executor.class))
            .build();
    return channelProvider.createMtlsChannelCredentials();
  }
}