code: /*
   * SPDX-License-Identifier: Apache-2.0
   * Copyright 2018-2019 The Feast 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
   *
   *     https://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 feast.serving.service.config;
  
  import com.google.inject.AbstractModule;
  import com.google.inject.Provides;
  import io.opentracing.Tracer;
  import io.opentracing.contrib.grpc.TracingServerInterceptor;
  import io.opentracing.noop.NoopTracerFactory;
  
  public class InstrumentationConfigModule extends AbstractModule {
  
    @Provides
    public Tracer tracer(ApplicationProperties applicationProperties) {
      if (!applicationProperties.getFeast().getTracing().isEnabled()) {
        return NoopTracerFactory.create();
      }
  
      if (!applicationProperties.getFeast().getTracing().getTracerName().equalsIgnoreCase("jaeger")) {
        throw new IllegalArgumentException("Only 'jaeger' tracer is supported for now.");
      }
  
      return io.jaegertracing.Configuration.fromEnv(
              applicationProperties.getFeast().getTracing().getServiceName())
          .getTracer();
    }
  
    @Provides
    public TracingServerInterceptor tracingInterceptor(Tracer tracer) {
      return TracingServerInterceptor.newBuilder().withTracer(tracer).build();
    }
  }
  