core, census, testing, interop-testing, android-interop-testing: move census dependency out of grpc-core (#6577)

Decouples grpc-core with census, while still preserve the default integration of census in grpc-core. Users wishing to enable census needs to add grpc-census to their runtime classpath.

- Created a grpc-census module:
    - Moved CensusStatsModule.java and CensusTracingModule.java into grpc-census from grpc-core. CensusModuleTests.java is also moved. They now belong to io.grpc.census package.
Moved DeprecatedCensusConstants.java into io.grpc.census.internal (is this necessary?) in grpc-census.
    - Created CensusStatsAccessor.java and CensusTracingAccessor.java, which are used to create census ClientInterceptor and ServerStreamTracer.Factory.
    - Everything in grpc-census are package private, except the accessor classes. They only publicly expose ClientInterceptor and ServerStreamTracer.Factory, no Census specific types are exposed.

- Use runtime reflection to load and apply census stats/tracing to channel/server builders, if grpc-census is found in runtime classpath.

- Removed special APIs on AbstractManagedChannelImplBuilder and AbstractServerImplBuilder for overriding census module. They are only used for testing. Now we changed tests to apply Census ClientInterceptor and ServerStreamTracer.Factory just as normal interceptor/stream tracer factory. Test writer is responsible for taking care of the ordering concerns of interceptors and stream tracer factories.

29 files changed, 447 insertions, 155 deletions

diff --git a/android-interop-testing/app/build.gradle b/android-interop-testing/app/build.gradle
index 16d0daf5f..63ce33190 100644
--- a/android-interop-testing/app/build.gradle
+++ b/android-interop-testing/app/build.gradle
@@ -73,6 +73,7 @@ dependencies {
 
     // You need to build grpc-java to obtain the grpc libraries below.
     implementation 'io.grpc:grpc-auth:1.27.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-census:1.27.0-SNAPSHOT' // CURRENT_GRPC_VERSION
     implementation 'io.grpc:grpc-okhttp:1.27.0-SNAPSHOT' // CURRENT_GRPC_VERSION
     implementation 'io.grpc:grpc-protobuf-lite:1.27.0-SNAPSHOT' // CURRENT_GRPC_VERSION
     implementation 'io.grpc:grpc-stub:1.27.0-SNAPSHOT' // CURRENT_GRPC_VERSION
diff --git a/census/BUILD.bazel b/census/BUILD.bazel
new file mode 100644
index 000000000..c0bf29b3f
--- /dev/null
+++ b/census/BUILD.bazel
@@ -0,0 +1,15 @@
+java_library(
+    name = "census",
+    srcs = glob([
+        "src/main/java/**/*.java",
+    ]),
+    visibility = ["//visibility:public"],
+    deps = [
+            "//api",
+            "//context",
+            "@com_google_code_findbugs_jsr305//jar",
+            "@com_google_guava_guava//jar",
+            "@io_opencensus_opencensus_api//jar",
+            "@io_opencensus_opencensus_contrib_grpc_metrics//jar",
+    ],
+)
diff --git a/census/build.gradle b/census/build.gradle
new file mode 100644
index 000000000..1c08390d1
--- /dev/null
+++ b/census/build.gradle
@@ -0,0 +1,43 @@
+plugins {
+    id "java"
+    id "maven-publish"
+}
+
+description = 'gRPC: Census'
+
+evaluationDependsOn(project(':grpc-api').path)
+
+dependencies {
+    compile project(':grpc-api')
+            
+    compile (libraries.opencensus_api) {
+        // prefer 3.0.2 from libraries instead of 3.0.1
+        exclude group: 'com.google.code.findbugs', module: 'jsr305'
+        // prefer 20.0 from libraries instead of 19.0
+        exclude group: 'com.google.guava', module: 'guava'
+        // we'll always be more up-to-date
+        exclude group: 'io.grpc', module: 'grpc-context'
+    }
+    
+    compile (libraries.opencensus_contrib_grpc_metrics) {
+        // prefer 3.0.2 from libraries instead of 3.0.1
+        exclude group: 'com.google.code.findbugs', module: 'jsr305'
+        // we'll always be more up-to-date
+        exclude group: 'io.grpc', module: 'grpc-context'
+        // prefer 20.0 from libraries instead of 19.0
+        exclude group: 'com.google.guava', module: 'guava'
+    }
+
+    testCompile project(':grpc-api').sourceSets.test.output,
+            project(':grpc-context').sourceSets.test.output,
+            project(':grpc-core').sourceSets.test.output,
+            project(':grpc-testing'),
+            libraries.guava_testlib,
+            libraries.opencensus_impl
+}
+
+javadoc {
+    failOnError false  // no public or protected classes found to document
+    exclude 'io/grpc/census/internal/**'
+    exclude 'io/grpc/census/Internal*'
+}
diff --git a/core/src/main/java/io/grpc/internal/CensusStatsModule.java b/census/src/main/java/io/grpc/census/CensusStatsModule.java
index 17262a065..d625a6f5c 100644
--- a/core/src/main/java/io/grpc/internal/CensusStatsModule.java
+++ b/census/src/main/java/io/grpc/census/CensusStatsModule.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.grpc.internal;
+package io.grpc.census;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkState;
@@ -35,6 +35,7 @@ import io.grpc.MethodDescriptor;
 import io.grpc.ServerStreamTracer;
 import io.grpc.Status;
 import io.grpc.StreamTracer;
+import io.grpc.census.internal.DeprecatedCensusConstants;
 import io.opencensus.contrib.grpc.metrics.RpcMeasureConstants;
 import io.opencensus.stats.Measure.MeasureDouble;
 import io.opencensus.stats.Measure.MeasureLong;
@@ -67,7 +68,7 @@ import javax.annotation.Nullable;
  * starts earlier than the ServerCall.  Therefore, only one tracer is created per stream/call and
  * it's the tracer that reports the summary to Census.
  */
-public final class CensusStatsModule {
+final class CensusStatsModule {
   private static final Logger logger = Logger.getLogger(CensusStatsModule.class.getName());
   private static final double NANOS_PER_MILLI = TimeUnit.MILLISECONDS.toNanos(1);
 
@@ -98,7 +99,7 @@ public final class CensusStatsModule {
   /**
    * Creates a {@link CensusStatsModule} with the given OpenCensus implementation.
    */
-  public CensusStatsModule(
+  CensusStatsModule(
       final Tagger tagger,
       final TagContextBinarySerializer tagCtxSerializer,
       StatsRecorder statsRecorder, Supplier<Stopwatch> stopwatchSupplier,
diff --git a/core/src/main/java/io/grpc/internal/CensusTracingModule.java b/census/src/main/java/io/grpc/census/CensusTracingModule.java
index b30c02d6a..e9e12941e 100644
--- a/core/src/main/java/io/grpc/internal/CensusTracingModule.java
+++ b/census/src/main/java/io/grpc/census/CensusTracingModule.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.grpc.internal;
+package io.grpc.census;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
diff --git a/census/src/main/java/io/grpc/census/InternalCensusStatsAccessor.java b/census/src/main/java/io/grpc/census/InternalCensusStatsAccessor.java
new file mode 100644
index 000000000..96be3258d
--- /dev/null
+++ b/census/src/main/java/io/grpc/census/InternalCensusStatsAccessor.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright 2019 The gRPC Authors
+ *
+ * Licensed 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 io.grpc.census;
+
+import com.google.common.base.Stopwatch;
+import com.google.common.base.Supplier;
+import io.grpc.ClientInterceptor;
+import io.grpc.Internal;
+import io.grpc.ServerStreamTracer;
+import io.opencensus.stats.StatsRecorder;
+import io.opencensus.tags.Tagger;
+import io.opencensus.tags.propagation.TagContextBinarySerializer;
+
+/**
+ * Accessor for getting {@link ClientInterceptor} or {@link ServerStreamTracer.Factory} with
+ * default Census stats implementation.
+ */
+@Internal
+public final class InternalCensusStatsAccessor {
+
+  private static final Supplier<Stopwatch> STOPWATCH_SUPPLIER = new Supplier<Stopwatch>() {
+    @Override
+    public Stopwatch get() {
+      return Stopwatch.createUnstarted();
+    }
+  };
+
+  // Prevent instantiation.
+  private InternalCensusStatsAccessor() {
+  }
+
+  /**
+   * Returns a {@link ClientInterceptor} with default stats implementation.
+   */
+  public static ClientInterceptor getClientInterceptor(
+      boolean recordStartedRpcs,
+      boolean recordFinishedRpcs,
+      boolean recordRealTimeMetrics) {
+    CensusStatsModule censusStats =
+        new CensusStatsModule(
+            STOPWATCH_SUPPLIER,
+            true, /* propagateTags */
+            recordStartedRpcs,
+            recordFinishedRpcs,
+            recordRealTimeMetrics);
+    return censusStats.getClientInterceptor();
+  }
+
+  /**
+   * Returns a {@link ClientInterceptor} with custom stats implementation.
+   */
+  public static ClientInterceptor getClientInterceptor(
+      Tagger tagger,
+      TagContextBinarySerializer tagCtxSerializer,
+      StatsRecorder statsRecorder,
+      Supplier<Stopwatch> stopwatchSupplier,
+      boolean propagateTags,
+      boolean recordStartedRpcs,
+      boolean recordFinishedRpcs,
+      boolean recordRealTimeMetrics) {
+    CensusStatsModule censusStats =
+        new CensusStatsModule(
+            tagger, tagCtxSerializer, statsRecorder, stopwatchSupplier,
+            propagateTags, recordStartedRpcs, recordFinishedRpcs, recordRealTimeMetrics);
+    return censusStats.getClientInterceptor();
+  }
+
+  /**
+   * Returns a {@link ServerStreamTracer.Factory} with default stats implementation.
+   */
+  public static ServerStreamTracer.Factory getServerStreamTracerFactory(
+      boolean recordStartedRpcs,
+      boolean recordFinishedRpcs,
+      boolean recordRealTimeMetrics) {
+    CensusStatsModule censusStats =
+        new CensusStatsModule(
+            STOPWATCH_SUPPLIER,
+            true, /* propagateTags */
+            recordStartedRpcs,
+            recordFinishedRpcs,
+            recordRealTimeMetrics);
+    return censusStats.getServerTracerFactory();
+  }
+
+  /**
+   * Returns a {@link ServerStreamTracer.Factory} with custom stats implementation.
+   */
+  public static ServerStreamTracer.Factory getServerStreamTracerFactory(
+      Tagger tagger,
+      TagContextBinarySerializer tagCtxSerializer,
+      StatsRecorder statsRecorder,
+      Supplier<Stopwatch> stopwatchSupplier,
+      boolean propagateTags,
+      boolean recordStartedRpcs,
+      boolean recordFinishedRpcs,
+      boolean recordRealTimeMetrics) {
+    CensusStatsModule censusStats =
+        new CensusStatsModule(
+            tagger, tagCtxSerializer, statsRecorder, stopwatchSupplier,
+            propagateTags, recordStartedRpcs, recordFinishedRpcs, recordRealTimeMetrics);
+    return censusStats.getServerTracerFactory();
+  }
+}
diff --git a/census/src/main/java/io/grpc/census/InternalCensusTracingAccessor.java b/census/src/main/java/io/grpc/census/InternalCensusTracingAccessor.java
new file mode 100644
index 000000000..2df6c5fb4
--- /dev/null
+++ b/census/src/main/java/io/grpc/census/InternalCensusTracingAccessor.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2019 The gRPC Authors
+ *
+ * Licensed 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 io.grpc.census;
+
+import io.grpc.ClientInterceptor;
+import io.grpc.Internal;
+import io.grpc.ServerStreamTracer;
+import io.opencensus.trace.Tracing;
+
+/**
+ * Accessor for getting {@link ClientInterceptor} or {@link ServerStreamTracer.Factory} with
+ * default Census tracing implementation.
+ */
+@Internal
+public final class InternalCensusTracingAccessor {
+
+  // Prevent instantiation.
+  private InternalCensusTracingAccessor() {
+  }
+
+  /**
+   * Returns a {@link ClientInterceptor} with default tracing implementation.
+   */
+  public static ClientInterceptor getClientInterceptor() {
+    CensusTracingModule censusTracing =
+        new CensusTracingModule(
+            Tracing.getTracer(),
+            Tracing.getPropagationComponent().getBinaryFormat());
+    return censusTracing.getClientInterceptor();
+  }
+
+  /**
+   * Returns a {@link ServerStreamTracer.Factory} with default stats implementation.
+   */
+  public static ServerStreamTracer.Factory getServerStreamTracerFactory() {
+    CensusTracingModule censusTracing =
+        new CensusTracingModule(
+            Tracing.getTracer(),
+            Tracing.getPropagationComponent().getBinaryFormat());
+    return censusTracing.getServerTracerFactory();
+  }
+}
diff --git a/core/src/main/java/io/grpc/internal/DeprecatedCensusConstants.java b/census/src/main/java/io/grpc/census/internal/DeprecatedCensusConstants.java
index 76be69b05..2b0a4763a 100644
--- a/core/src/main/java/io/grpc/internal/DeprecatedCensusConstants.java
+++ b/census/src/main/java/io/grpc/census/internal/DeprecatedCensusConstants.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.grpc.internal;
+package io.grpc.census.internal;
 
 import com.google.common.annotations.VisibleForTesting;
 import io.opencensus.contrib.grpc.metrics.RpcMeasureConstants;
diff --git a/core/src/test/java/io/grpc/internal/CensusModulesTest.java b/census/src/test/java/io/grpc/census/CensusModulesTest.java
index 9ceb063fb..8187d3845 100644
--- a/core/src/test/java/io/grpc/internal/CensusModulesTest.java
+++ b/census/src/test/java/io/grpc/census/CensusModulesTest.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.grpc.internal;
+package io.grpc.census;
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
@@ -56,7 +56,10 @@ import io.grpc.ServerCall;
 import io.grpc.ServerCallHandler;
 import io.grpc.ServerServiceDefinition;
 import io.grpc.ServerStreamTracer;
+import io.grpc.ServerStreamTracer.ServerCallInfo;
 import io.grpc.Status;
+import io.grpc.census.internal.DeprecatedCensusConstants;
+import io.grpc.internal.FakeClock;
 import io.grpc.internal.testing.StatsTestUtils;
 import io.grpc.internal.testing.StatsTestUtils.FakeStatsRecorder;
 import io.grpc.internal.testing.StatsTestUtils.FakeTagContextBinarySerializer;
@@ -95,6 +98,7 @@ import java.util.List;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
+import javax.annotation.Nullable;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -1044,7 +1048,7 @@ public class CensusModulesTest {
     assertSame(spyServerSpan, ContextUtils.getValue(filteredContext));
 
     serverStreamTracer.serverCallStarted(
-        new ServerCallInfoImpl<>(method, Attributes.EMPTY, null));
+        new CallInfo<>(method, Attributes.EMPTY, null));
 
     verify(spyServerSpan, never()).end(any(EndSpanOptions.class));
 
@@ -1087,7 +1091,7 @@ public class CensusModulesTest {
     serverStreamTracer.filterContext(Context.ROOT);
 
     serverStreamTracer.serverCallStarted(
-        new ServerCallInfoImpl<>(sampledMethod, Attributes.EMPTY, null));
+        new CallInfo<>(sampledMethod, Attributes.EMPTY, null));
 
     serverStreamTracer.streamClosed(Status.CANCELLED);
 
@@ -1250,8 +1254,39 @@ public class CensusModulesTest {
         new Function<AggregationData, Long>() {
           @Override
           public Long apply(AggregationData arg) {
-            return ((io.opencensus.stats.AggregationData.MeanData) arg).getCount();
+            return ((AggregationData.MeanData) arg).getCount();
           }
         });
   }
+
+  private static class CallInfo<ReqT, RespT> extends ServerCallInfo<ReqT, RespT> {
+    private final MethodDescriptor<ReqT, RespT> methodDescriptor;
+    private final Attributes attributes;
+    private final String authority;
+
+    CallInfo(
+        MethodDescriptor<ReqT, RespT> methodDescriptor,
+        Attributes attributes,
+        @Nullable String authority) {
+      this.methodDescriptor = methodDescriptor;
+      this.attributes = attributes;
+      this.authority = authority;
+    }
+
+    @Override
+    public MethodDescriptor<ReqT, RespT> getMethodDescriptor() {
+      return methodDescriptor;
+    }
+
+    @Override
+    public Attributes getAttributes() {
+      return attributes;
+    }
+
+    @Nullable
+    @Override
+    public String getAuthority() {
+      return authority;
+    }
+  }
 }
diff --git a/core/BUILD.bazel b/core/BUILD.bazel
index 5b4dbe8d5..c6e1ffbb6 100644
--- a/core/BUILD.bazel
+++ b/core/BUILD.bazel
@@ -38,8 +38,6 @@ java_library(
         "@com_google_errorprone_error_prone_annotations//jar",
         "@com_google_guava_guava//jar",
         "@com_google_j2objc_j2objc_annotations//jar",
-        "@io_opencensus_opencensus_api//jar",
-        "@io_opencensus_opencensus_contrib_grpc_metrics//jar",
         "@io_perfmark_perfmark_api//jar",
         "@org_codehaus_mojo_animal_sniffer_annotations//jar",
     ],
diff --git a/core/build.gradle b/core/build.gradle
index ee12f834d..e4a218cf3 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -20,25 +20,14 @@ dependencies {
     compile (libraries.perfmark) {
         exclude group: 'com.google.errorprone', module: 'error_prone_annotations'
     }
-    compile (libraries.opencensus_api) {
-        // prefer our own versions instead of opencensus-api's dependency
-        exclude group: 'com.google.code.findbugs', module: 'jsr305'
-        exclude group: 'com.google.guava', module: 'guava'
-        exclude group: 'io.grpc', module: 'grpc-context'
-    }
-    compile (libraries.opencensus_contrib_grpc_metrics) {
-        // prefer our own versions instead of opencensus-contrib's dependency
-        exclude group: 'com.google.code.findbugs', module: 'jsr305'
-        exclude group: 'io.grpc', module: 'grpc-context'
-        exclude group: 'com.google.guava', module: 'guava'
-    }
 
     testCompile project(':grpc-context').sourceSets.test.output,
             project(':grpc-api').sourceSets.test.output,
             project(':grpc-testing'),
             project(':grpc-grpclb'),
-            libraries.guava_testlib,
-            libraries.opencensus_impl
+            libraries.guava_testlib
+    
+    testRuntimeOnly project(':grpc-census')
 
     jmh project(':grpc-testing')
 
diff --git a/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java b/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
index 49c9fae24..93883da92 100644
--- a/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
+++ b/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
@@ -33,7 +33,8 @@ import io.grpc.ManagedChannelBuilder;
 import io.grpc.NameResolver;
 import io.grpc.NameResolverRegistry;
 import io.grpc.ProxyDetector;
-import io.opencensus.trace.Tracing;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.net.SocketAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -45,6 +46,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
 /**
@@ -56,6 +59,9 @@ public abstract class AbstractManagedChannelImplBuilder
         <T extends AbstractManagedChannelImplBuilder<T>> extends ManagedChannelBuilder<T> {
   private static final String DIRECT_ADDRESS_SCHEME = "directaddress";
 
+  private static final Logger log =
+      Logger.getLogger(AbstractManagedChannelImplBuilder.class.getName());
+
   public static ManagedChannelBuilder<?> forAddress(String name, int port) {
     throw new UnsupportedOperationException("Subclass failed to hide static factory");
   }
@@ -184,9 +190,6 @@ public abstract class AbstractManagedChannelImplBuilder
   private boolean recordRealTimeMetrics = false;
   private boolean tracingEnabled = true;
 
-  @Nullable
-  private CensusStatsModule censusStatsOverride;
-
   protected AbstractManagedChannelImplBuilder(String target) {
     this.target = Preconditions.checkNotNull(target, "target");
     this.directServerAddress = null;
@@ -376,15 +379,6 @@ public abstract class AbstractManagedChannelImplBuilder
     return thisT();
   }
 
-  /**
-   * Override the default stats implementation.
-   */
-  @VisibleForTesting
-  protected final T overrideCensusStatsModule(CensusStatsModule censusStats) {
-    this.censusStatsOverride = censusStats;
-    return thisT();
-  }
-
   @Override
   public T proxyDetector(@Nullable ProxyDetector proxyDetector) {
     this.proxyDetector = proxyDetector;
@@ -565,22 +559,49 @@ public abstract class AbstractManagedChannelImplBuilder
     temporarilyDisableRetry = false;
     if (statsEnabled) {
       temporarilyDisableRetry = true;
-      CensusStatsModule censusStats = this.censusStatsOverride;
-      if (censusStats == null) {
-        censusStats = new CensusStatsModule(
-            GrpcUtil.STOPWATCH_SUPPLIER, true, recordStartedRpcs, recordFinishedRpcs,
-            recordRealTimeMetrics);
+      ClientInterceptor statsInterceptor = null;
+      try {
+        Class<?> censusStatsAccessor =
+            Class.forName("io.grpc.census.InternalCensusStatsAccessor");
+        Method getClientInterceptorMethod =
+            censusStatsAccessor.getDeclaredMethod(
+                "getClientInterceptor",
+                boolean.class,
+                boolean.class,
+                boolean.class);
+        statsInterceptor =
+            (ClientInterceptor) getClientInterceptorMethod
+                .invoke(
+                    null,
+                    recordStartedRpcs,
+                    recordFinishedRpcs,
+                    recordRealTimeMetrics);
+      } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException
+          | InvocationTargetException e) {
+        log.log(Level.FINE, "Unable to apply census stats", e);
+      }
+      if (statsInterceptor != null) {
+        // First interceptor runs last (see ClientInterceptors.intercept()), so that no
+        // other interceptor can override the tracer factory we set in CallOptions.
+        effectiveInterceptors.add(0, statsInterceptor);
       }
-      // First interceptor runs last (see ClientInterceptors.intercept()), so that no
-      // other interceptor can override the tracer factory we set in CallOptions.
-      effectiveInterceptors.add(0, censusStats.getClientInterceptor());
     }
     if (tracingEnabled) {
       temporarilyDisableRetry = true;
-      CensusTracingModule censusTracing =
-          new CensusTracingModule(Tracing.getTracer(),
-              Tracing.getPropagationComponent().getBinaryFormat());
-      effectiveInterceptors.add(0, censusTracing.getClientInterceptor());
+      ClientInterceptor tracingInterceptor = null;
+      try {
+        Class<?> censusTracingAccessor =
+            Class.forName("io.grpc.census.InternalCensusTracingAccessor");
+        Method getClientInterceptroMethod =
+            censusTracingAccessor.getDeclaredMethod("getClientInterceptor");
+        tracingInterceptor = (ClientInterceptor) getClientInterceptroMethod.invoke(null);
+      } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException
+          | InvocationTargetException e) {
+        log.log(Level.FINE, "Unable to apply census tracing", e);
+      }
+      if (tracingInterceptor != null) {
+        effectiveInterceptors.add(0, tracingInterceptor);
+      }
     }
     return effectiveInterceptors;
   }
diff --git a/core/src/main/java/io/grpc/internal/AbstractServerImplBuilder.java b/core/src/main/java/io/grpc/internal/AbstractServerImplBuilder.java
index 3b2bed604..ff151d1a6 100644
--- a/core/src/main/java/io/grpc/internal/AbstractServerImplBuilder.java
+++ b/core/src/main/java/io/grpc/internal/AbstractServerImplBuilder.java
@@ -37,12 +37,15 @@ import io.grpc.ServerMethodDefinition;
 import io.grpc.ServerServiceDefinition;
 import io.grpc.ServerStreamTracer;
 import io.grpc.ServerTransportFilter;
-import io.opencensus.trace.Tracing;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
 /**
@@ -53,6 +56,8 @@ import javax.annotation.Nullable;
 public abstract class AbstractServerImplBuilder<T extends AbstractServerImplBuilder<T>>
         extends ServerBuilder<T> {
 
+  private static final Logger log = Logger.getLogger(AbstractServerImplBuilder.class.getName());
+
   public static ServerBuilder<?> forPort(int port) {
     throw new UnsupportedOperationException("Subclass failed to hide static factory");
   }
@@ -80,7 +85,6 @@ public abstract class AbstractServerImplBuilder<T extends AbstractServerImplBuil
   CompressorRegistry compressorRegistry = DEFAULT_COMPRESSOR_REGISTRY;
   long handshakeTimeoutMillis = DEFAULT_HANDSHAKE_TIMEOUT_MILLIS;
   Deadline.Ticker ticker = Deadline.getSystemTicker();
-  @Nullable private CensusStatsModule censusStatsOverride;
   private boolean statsEnabled = true;
   private boolean recordStartedRpcs = true;
   private boolean recordFinishedRpcs = true;
@@ -165,15 +169,6 @@ public abstract class AbstractServerImplBuilder<T extends AbstractServerImplBuil
     return thisT();
   }
 
-  /**
-   * Override the default stats implementation.
-   */
-  @VisibleForTesting
-  protected final T overrideCensusStatsModule(@Nullable CensusStatsModule censusStats) {
-    this.censusStatsOverride = censusStats;
-    return thisT();
-  }
-
   @VisibleForTesting
   public final T setTransportTracerFactory(TransportTracer.Factory transportTracerFactory) {
     this.transportTracerFactory = transportTracerFactory;
@@ -241,19 +236,47 @@ public abstract class AbstractServerImplBuilder<T extends AbstractServerImplBuil
   final List<? extends ServerStreamTracer.Factory> getTracerFactories() {
     ArrayList<ServerStreamTracer.Factory> tracerFactories = new ArrayList<>();
     if (statsEnabled) {
-      CensusStatsModule censusStats = censusStatsOverride;
-      if (censusStats == null) {
-        censusStats = new CensusStatsModule(
-            GrpcUtil.STOPWATCH_SUPPLIER, true, recordStartedRpcs, recordFinishedRpcs,
-            recordRealTimeMetrics);
+      ServerStreamTracer.Factory censusStatsTracerFactory = null;
+      try {
+        Class<?> censusStatsAccessor =
+            Class.forName("io.grpc.census.InternalCensusStatsAccessor");
+        Method getServerStreamTracerFactoryMethod =
+            censusStatsAccessor.getDeclaredMethod(
+                "getServerStreamTracerFactory",
+                boolean.class,
+                boolean.class,
+                boolean.class);
+        censusStatsTracerFactory =
+            (ServerStreamTracer.Factory) getServerStreamTracerFactoryMethod
+                .invoke(
+                    null,
+                    recordStartedRpcs,
+                    recordFinishedRpcs,
+                    recordRealTimeMetrics);
+      } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException
+          | InvocationTargetException e) {
+        log.log(Level.FINE, "Unable to apply census stats", e);
+      }
+      if (censusStatsTracerFactory != null) {
+        tracerFactories.add(censusStatsTracerFactory);
       }
-      tracerFactories.add(censusStats.getServerTracerFactory());
     }
     if (tracingEnabled) {
-      CensusTracingModule censusTracing =
-          new CensusTracingModule(Tracing.getTracer(),
-              Tracing.getPropagationComponent().getBinaryFormat());
-      tracerFactories.add(censusTracing.getServerTracerFactory());
+      ServerStreamTracer.Factory tracingStreamTracerFactory = null;
+      try {
+        Class<?> censusTracingAccessor =
+            Class.forName("io.grpc.census.InternalCensusTracingAccessor");
+        Method getServerStreamTracerFactoryMethod =
+            censusTracingAccessor.getDeclaredMethod("getServerStreamTracerFactory");
+        tracingStreamTracerFactory =
+            (ServerStreamTracer.Factory) getServerStreamTracerFactoryMethod.invoke(null);
+      } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException
+          | InvocationTargetException e) {
+        log.log(Level.FINE, "Unable to apply census tracing", e);
+      }
+      if (tracingStreamTracerFactory != null) {
+        tracerFactories.add(tracingStreamTracerFactory);
+      }
     }
     tracerFactories.addAll(streamTracerFactories);
     tracerFactories.trimToSize();
diff --git a/core/src/test/java/io/grpc/internal/AbstractManagedChannelImplBuilderTest.java b/core/src/test/java/io/grpc/internal/AbstractManagedChannelImplBuilderTest.java
index 371fbd674..1a39671af 100644
--- a/core/src/test/java/io/grpc/internal/AbstractManagedChannelImplBuilderTest.java
+++ b/core/src/test/java/io/grpc/internal/AbstractManagedChannelImplBuilderTest.java
@@ -36,9 +36,6 @@ import io.grpc.CompressorRegistry;
 import io.grpc.DecompressorRegistry;
 import io.grpc.MethodDescriptor;
 import io.grpc.NameResolver;
-import io.grpc.internal.testing.StatsTestUtils.FakeStatsRecorder;
-import io.grpc.internal.testing.StatsTestUtils.FakeTagContextBinarySerializer;
-import io.grpc.internal.testing.StatsTestUtils.FakeTagger;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.net.URI;
@@ -284,10 +281,10 @@ public class AbstractManagedChannelImplBuilderTest {
     builder.intercept(DUMMY_USER_INTERCEPTOR);
     List<ClientInterceptor> effectiveInterceptors = builder.getEffectiveInterceptors();
     assertEquals(3, effectiveInterceptors.size());
-    assertThat(effectiveInterceptors.get(0))
-        .isInstanceOf(CensusTracingModule.TracingClientInterceptor.class);
-    assertThat(effectiveInterceptors.get(1))
-        .isInstanceOf(CensusStatsModule.StatsClientInterceptor.class);
+    assertThat(effectiveInterceptors.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusTracingModule$TracingClientInterceptor");
+    assertThat(effectiveInterceptors.get(1).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusStatsModule$StatsClientInterceptor");
     assertThat(effectiveInterceptors.get(2)).isSameInstanceAs(DUMMY_USER_INTERCEPTOR);
   }
 
@@ -297,8 +294,8 @@ public class AbstractManagedChannelImplBuilderTest {
     builder.setStatsEnabled(false);
     List<ClientInterceptor> effectiveInterceptors = builder.getEffectiveInterceptors();
     assertEquals(2, effectiveInterceptors.size());
-    assertThat(effectiveInterceptors.get(0))
-        .isInstanceOf(CensusTracingModule.TracingClientInterceptor.class);
+    assertThat(effectiveInterceptors.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusTracingModule$TracingClientInterceptor");
     assertThat(effectiveInterceptors.get(1)).isSameInstanceAs(DUMMY_USER_INTERCEPTOR);
   }
 
@@ -308,8 +305,8 @@ public class AbstractManagedChannelImplBuilderTest {
     builder.setTracingEnabled(false);
     List<ClientInterceptor> effectiveInterceptors = builder.getEffectiveInterceptors();
     assertEquals(2, effectiveInterceptors.size());
-    assertThat(effectiveInterceptors.get(0))
-        .isInstanceOf(CensusStatsModule.StatsClientInterceptor.class);
+    assertThat(effectiveInterceptors.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusStatsModule$StatsClientInterceptor");
     assertThat(effectiveInterceptors.get(1)).isSameInstanceAs(DUMMY_USER_INTERCEPTOR);
   }
 
@@ -500,24 +497,10 @@ public class AbstractManagedChannelImplBuilderTest {
   static class Builder extends AbstractManagedChannelImplBuilder<Builder> {
     Builder(String target) {
       super(target);
-      overrideCensusStatsModule(
-          new CensusStatsModule(
-              new FakeTagger(),
-              new FakeTagContextBinarySerializer(),
-              new FakeStatsRecorder(),
-              GrpcUtil.STOPWATCH_SUPPLIER,
-              true, true, true, true));
     }
 
     Builder(SocketAddress directServerAddress, String authority) {
       super(directServerAddress, authority);
-      overrideCensusStatsModule(
-          new CensusStatsModule(
-              new FakeTagger(),
-              new FakeTagContextBinarySerializer(),
-              new FakeStatsRecorder(),
-              GrpcUtil.STOPWATCH_SUPPLIER,
-              true, true, true, true));
     }
 
     @Override
diff --git a/core/src/test/java/io/grpc/internal/AbstractServerImplBuilderTest.java b/core/src/test/java/io/grpc/internal/AbstractServerImplBuilderTest.java
index 0021d9224..77aced782 100644
--- a/core/src/test/java/io/grpc/internal/AbstractServerImplBuilderTest.java
+++ b/core/src/test/java/io/grpc/internal/AbstractServerImplBuilderTest.java
@@ -21,9 +21,6 @@ import static org.junit.Assert.assertEquals;
 
 import io.grpc.Metadata;
 import io.grpc.ServerStreamTracer;
-import io.grpc.internal.testing.StatsTestUtils.FakeStatsRecorder;
-import io.grpc.internal.testing.StatsTestUtils.FakeTagContextBinarySerializer;
-import io.grpc.internal.testing.StatsTestUtils.FakeTagger;
 import java.io.File;
 import java.util.List;
 import org.junit.Test;
@@ -51,8 +48,10 @@ public class AbstractServerImplBuilderTest {
     List<? extends ServerStreamTracer.Factory> factories = builder.getTracerFactories();
 
     assertEquals(3, factories.size());
-    assertThat(factories.get(0)).isInstanceOf(CensusStatsModule.ServerTracerFactory.class);
-    assertThat(factories.get(1)).isInstanceOf(CensusTracingModule.ServerTracerFactory.class);
+    assertThat(factories.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusStatsModule$ServerTracerFactory");
+    assertThat(factories.get(1).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusTracingModule$ServerTracerFactory");
     assertThat(factories.get(2)).isSameInstanceAs(DUMMY_USER_TRACER);
   }
 
@@ -64,7 +63,8 @@ public class AbstractServerImplBuilderTest {
     List<? extends ServerStreamTracer.Factory> factories = builder.getTracerFactories();
 
     assertEquals(2, factories.size());
-    assertThat(factories.get(0)).isInstanceOf(CensusTracingModule.ServerTracerFactory.class);
+    assertThat(factories.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusTracingModule$ServerTracerFactory");
     assertThat(factories.get(1)).isSameInstanceAs(DUMMY_USER_TRACER);
   }
 
@@ -76,7 +76,8 @@ public class AbstractServerImplBuilderTest {
     List<? extends ServerStreamTracer.Factory> factories = builder.getTracerFactories();
 
     assertEquals(2, factories.size());
-    assertThat(factories.get(0)).isInstanceOf(CensusStatsModule.ServerTracerFactory.class);
+    assertThat(factories.get(0).getClass().getName())
+        .isEqualTo("io.grpc.census.CensusStatsModule$ServerTracerFactory");
     assertThat(factories.get(1)).isSameInstanceAs(DUMMY_USER_TRACER);
   }
 
@@ -90,15 +91,6 @@ public class AbstractServerImplBuilderTest {
   }
 
   static class Builder extends AbstractServerImplBuilder<Builder> {
-    Builder() {
-      overrideCensusStatsModule(
-          new CensusStatsModule(
-              new FakeTagger(),
-              new FakeTagContextBinarySerializer(),
-              new FakeStatsRecorder(),
-              GrpcUtil.STOPWATCH_SUPPLIER,
-              true, true, true, true));
-    }
 
     @Override
     protected List<io.grpc.internal.InternalServer> buildTransportServers(
diff --git a/interop-testing/build.gradle b/interop-testing/build.gradle
index b11ed26eb..169007e51 100644
--- a/interop-testing/build.gradle
+++ b/interop-testing/build.gradle
@@ -18,6 +18,7 @@ evaluationDependsOn(project(':grpc-context').path)
 dependencies {
     compile project(':grpc-alts'),
             project(':grpc-auth'),
+            project(':grpc-census'),
             project(':grpc-core'),
             project(':grpc-netty'),
             project(':grpc-okhttp'),
diff --git a/interop-testing/src/main/java/io/grpc/testing/integration/AbstractInteropTest.java b/interop-testing/src/main/java/io/grpc/testing/integration/AbstractInteropTest.java
index 65274cad7..dc8819eaf 100644
--- a/interop-testing/src/main/java/io/grpc/testing/integration/AbstractInteropTest.java
+++ b/interop-testing/src/main/java/io/grpc/testing/integration/AbstractInteropTest.java
@@ -61,9 +61,9 @@ import io.grpc.ServerStreamTracer;
 import io.grpc.Status;
 import io.grpc.StatusRuntimeException;
 import io.grpc.auth.MoreCallCredentials;
+import io.grpc.census.InternalCensusStatsAccessor;
+import io.grpc.census.internal.DeprecatedCensusConstants;
 import io.grpc.internal.AbstractServerImplBuilder;
-import io.grpc.internal.CensusStatsModule;
-import io.grpc.internal.DeprecatedCensusConstants;
 import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.testing.StatsTestUtils;
 import io.grpc.internal.testing.StatsTestUtils.FakeStatsRecorder;
@@ -240,15 +240,15 @@ public abstract class AbstractInteropTest {
         .addStreamTracerFactory(serverStreamTracerFactory);
     if (builder instanceof AbstractServerImplBuilder) {
       customCensusModulePresent = true;
+      ServerStreamTracer.Factory censusTracerFactory =
+          InternalCensusStatsAccessor
+              .getServerStreamTracerFactory(
+                  tagger, tagContextBinarySerializer, serverStatsRecorder,
+                  GrpcUtil.STOPWATCH_SUPPLIER,
+                  true, true, true, false /* real-time metrics */);
       AbstractServerImplBuilder<?> sb = (AbstractServerImplBuilder<?>) builder;
-      io.grpc.internal.TestingAccessor.setStatsImplementation(
-          sb,
-          new CensusStatsModule(
-              tagger,
-              tagContextBinarySerializer,
-              serverStatsRecorder,
-              GrpcUtil.STOPWATCH_SUPPLIER,
-              true, true, true, false /* real-time metrics */));
+      io.grpc.internal.TestingAccessor.setStatsEnabled(sb, false);
+      sb.addStreamTracerFactory(censusTracerFactory);
     }
     if (metricsExpected()) {
       assertThat(builder).isInstanceOf(AbstractServerImplBuilder.class);
@@ -353,10 +353,13 @@ public abstract class AbstractInteropTest {
     return null;
   }
 
-  protected final CensusStatsModule createClientCensusStatsModule() {
-    return new CensusStatsModule(
-        tagger, tagContextBinarySerializer, clientStatsRecorder, GrpcUtil.STOPWATCH_SUPPLIER,
-        true, true, true, false /* real-time metrics */);
+  protected final ClientInterceptor createCensusStatsClientInterceptor() {
+    return
+        InternalCensusStatsAccessor
+            .getClientInterceptor(
+                tagger, tagContextBinarySerializer, clientStatsRecorder,
+                GrpcUtil.STOPWATCH_SUPPLIER,
+                true, true, true, false /* real-time metrics */);
   }
 
   /**
diff --git a/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java b/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
index 486c51894..714306f92 100644
--- a/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
+++ b/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
@@ -450,9 +450,9 @@ public class TestServiceClient {
         }
         builder = okBuilder;
       }
-      io.grpc.internal.TestingAccessor.setStatsImplementation(
-          builder, createClientCensusStatsModule());
-      return builder.build();
+      // Disable the default census stats interceptor, use testing interceptor instead.
+      io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+      return builder.intercept(createCensusStatsClientInterceptor()).build();
     }
 
     @Override
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/AutoWindowSizingOnTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/AutoWindowSizingOnTest.java
index 126096667..462ad480a 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/AutoWindowSizingOnTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/AutoWindowSizingOnTest.java
@@ -46,8 +46,8 @@ public class AutoWindowSizingOnTest extends AbstractInteropTest {
     NettyChannelBuilder builder = NettyChannelBuilder.forAddress(getListenAddress())
         .negotiationType(NegotiationType.PLAINTEXT)
         .maxInboundMessageSize(AbstractInteropTest.MAX_MESSAGE_SIZE);
-    io.grpc.internal.TestingAccessor.setStatsImplementation(
-        builder, createClientCensusStatsModule());
-    return builder.build();
+    // Disable the default census stats interceptor, use testing interceptor instead.
+    io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+    return builder.intercept(createCensusStatsClientInterceptor()).build();
   }
 }
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyLocalChannelTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyLocalChannelTest.java
index 0410a7281..d934621f7 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyLocalChannelTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyLocalChannelTest.java
@@ -57,9 +57,9 @@ public class Http2NettyLocalChannelTest extends AbstractInteropTest {
         .eventLoopGroup(eventLoopGroup)
         .flowControlWindow(65 * 1024)
         .maxInboundMessageSize(AbstractInteropTest.MAX_MESSAGE_SIZE);
-    io.grpc.internal.TestingAccessor.setStatsImplementation(
-        builder, createClientCensusStatsModule());
-    return builder.build();
+    // Disable the default census stats interceptor, use testing interceptor instead.
+    io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+    return builder.intercept(createCensusStatsClientInterceptor()).build();
   }
 
   @Override
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
index 74c5147cc..76726d180 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
@@ -71,9 +71,9 @@ public class Http2NettyTest extends AbstractInteropTest {
               .trustManager(TestUtils.loadX509Cert("ca.pem"))
               .ciphers(TestUtils.preferredTestCiphers(), SupportedCipherSuiteFilter.INSTANCE)
               .build());
-      io.grpc.internal.TestingAccessor.setStatsImplementation(
-          builder, createClientCensusStatsModule());
-      return builder.build();
+      // Disable the default census stats interceptor, use testing interceptor instead.
+      io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+      return builder.intercept(createCensusStatsClientInterceptor()).build();
     } catch (Exception ex) {
       throw new RuntimeException(ex);
     }
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/Http2OkHttpTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/Http2OkHttpTest.java
index 4830fa901..927b0ed44 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/Http2OkHttpTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/Http2OkHttpTest.java
@@ -100,15 +100,15 @@ public class Http2OkHttpTest extends AbstractInteropTest {
             .build())
         .overrideAuthority(GrpcUtil.authorityFromHostAndPort(
             TestUtils.TEST_SERVER_HOST, port));
-    io.grpc.internal.TestingAccessor.setStatsImplementation(
-        builder, createClientCensusStatsModule());
     try {
       builder.sslSocketFactory(TestUtils.newSslSocketFactoryForCa(Platform.get().getProvider(),
           TestUtils.loadCert("ca.pem")));
     } catch (Exception e) {
       throw new RuntimeException(e);
     }
-    return builder;
+    // Disable the default census stats interceptor, use testing interceptor instead.
+    io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+    return builder.intercept(createCensusStatsClientInterceptor());
   }
 
   @Test
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/InProcessTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/InProcessTest.java
index 32c753b20..3592f4b96 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/InProcessTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/InProcessTest.java
@@ -38,9 +38,9 @@ public class InProcessTest extends AbstractInteropTest {
   @Override
   protected ManagedChannel createChannel() {
     InProcessChannelBuilder builder = InProcessChannelBuilder.forName(SERVER_NAME);
-    io.grpc.internal.TestingAccessor.setStatsImplementation(
-        builder, createClientCensusStatsModule());
-    return builder.build();
+    // Disable the default census stats interceptor, use testing interceptor instead.
+    io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+    return builder.intercept(createCensusStatsClientInterceptor()).build();
   }
 
   @Override
diff --git a/interop-testing/src/test/java/io/grpc/testing/integration/TransportCompressionTest.java b/interop-testing/src/test/java/io/grpc/testing/integration/TransportCompressionTest.java
index e99ba561b..a776a8312 100644
--- a/interop-testing/src/test/java/io/grpc/testing/integration/TransportCompressionTest.java
+++ b/interop-testing/src/test/java/io/grpc/testing/integration/TransportCompressionTest.java
@@ -165,9 +165,9 @@ public class TransportCompressionTest extends AbstractInteropTest {
           }
         })
         .usePlaintext();
-    io.grpc.internal.TestingAccessor.setStatsImplementation(
-        builder, createClientCensusStatsModule());
-    return builder.build();
+    // Disable the default census stats interceptor, use testing interceptor instead.
+    io.grpc.internal.TestingAccessor.setStatsEnabled(builder, false);
+    return builder.intercept(createCensusStatsClientInterceptor()).build();
   }
 
   /**
diff --git a/repositories.bzl b/repositories.bzl
index 3f129cadb..78cdf086f 100644
--- a/repositories.bzl
+++ b/repositories.bzl
@@ -70,6 +70,7 @@ IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS = {
     "io.grpc:grpc-alts": "@io_grpc_grpc_java//alts",
     "io.grpc:grpc-api": "@io_grpc_grpc_java//api",
     "io.grpc:grpc-auth": "@io_grpc_grpc_java//auth",
+    "io.grpc:grpc-census": "@io_grpc_grpc_java//census",
     "io.grpc:grpc-context": "@io_grpc_grpc_java//context",
     "io.grpc:grpc-core": "@io_grpc_grpc_java//core:core_maven",
     "io.grpc:grpc-grpclb": "@io_grpc_grpc_java//grpclb",
diff --git a/settings.gradle b/settings.gradle
index 0ce56b202..7881b4e80 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -29,6 +29,7 @@ include ":grpc-api"
 include ":grpc-core"
 include ":grpc-context"
 include ":grpc-stub"
+include ":grpc-census"
 include ":grpc-auth"
 include ":grpc-okhttp"
 include ":grpc-protobuf"
@@ -51,6 +52,7 @@ project(':grpc-api').projectDir = "$rootDir/api" as File
 project(':grpc-core').projectDir = "$rootDir/core" as File
 project(':grpc-context').projectDir = "$rootDir/context" as File
 project(':grpc-stub').projectDir = "$rootDir/stub" as File
+project(':grpc-census').projectDir = "$rootDir/census" as File
 project(':grpc-auth').projectDir = "$rootDir/auth" as File
 project(':grpc-okhttp').projectDir = "$rootDir/okhttp" as File
 project(':grpc-protobuf').projectDir = "$rootDir/protobuf" as File
diff --git a/testing/BUILD.bazel b/testing/BUILD.bazel
index 09d0796fa..f1e9a5743 100644
--- a/testing/BUILD.bazel
+++ b/testing/BUILD.bazel
@@ -31,5 +31,6 @@ java_library(
     deps = [
         "//api",
         "//core:internal",
+        "@io_opencensus_opencensus_api//jar",
     ],
 )
diff --git a/testing/build.gradle b/testing/build.gradle
index 619f13e7d..7365d7d53 100644
--- a/testing/build.gradle
+++ b/testing/build.gradle
@@ -14,6 +14,15 @@ dependencies {
             project(':grpc-stub'),
             libraries.junit
 
+    compile (libraries.opencensus_api) {
+        // prefer 3.0.2 from libraries instead of 3.0.1
+        exclude group: 'com.google.code.findbugs', module: 'jsr305'
+        // prefer 20.0 from libraries instead of 19.0
+        exclude group: 'com.google.guava', module: 'guava'
+        // we'll always be more up-to-date
+        exclude group: 'io.grpc', module: 'grpc-context'
+    }
+
     testCompile (libraries.mockito) {
         // prefer our own versions instead of mockito's dependency
         exclude group: 'org.hamcrest', module: 'hamcrest-core'
diff --git a/testing/src/main/java/io/grpc/internal/TestingAccessor.java b/testing/src/main/java/io/grpc/internal/TestingAccessor.java
index 4c994299b..d5b00e025 100644
--- a/testing/src/main/java/io/grpc/internal/TestingAccessor.java
+++ b/testing/src/main/java/io/grpc/internal/TestingAccessor.java
@@ -21,19 +21,20 @@ package io.grpc.internal;
  */
 public final class TestingAccessor {
   /**
-   * Sets a custom stats implementation for tests.
+   * Disable or enable client side census stats features.
    */
-  public static void setStatsImplementation(
-      AbstractManagedChannelImplBuilder<?> builder, CensusStatsModule censusStats) {
-    builder.overrideCensusStatsModule(censusStats);
+  public static void setStatsEnabled(
+      AbstractManagedChannelImplBuilder<?> builder, boolean statsEnabled) {
+    builder.setStatsEnabled(statsEnabled);
   }
 
   /**
-   * Sets a custom stats implementation for tests.
+   * Disable or enable server side census stats features.
    */
-  public static void setStatsImplementation(
-      AbstractServerImplBuilder<?> builder, CensusStatsModule censusStats) {
-    builder.overrideCensusStatsModule(censusStats);
+  public static void setStatsEnabled(
+      AbstractServerImplBuilder<?> builder,
+      boolean statsEnabled) {
+    builder.setStatsEnabled(statsEnabled);
   }
 
   private TestingAccessor() {