statefun-flink/statefun-flink-datastream/src/main/java/org/apache/flink/statefun/flink/datastream/RequestReplyFunctionBuilder.java

/*
 * 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.flink.statefun.flink.datastream;

import java.net.URI;
import java.time.Duration;
import org.apache.flink.annotation.Internal;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.node.ObjectNode;
import org.apache.flink.statefun.flink.core.httpfn.DefaultHttpRequestReplyClientSpec;
import org.apache.flink.statefun.flink.core.httpfn.HttpFunctionEndpointSpec;
import org.apache.flink.statefun.flink.core.httpfn.TargetFunctions;
import org.apache.flink.statefun.flink.core.httpfn.TransportClientConstants;
import org.apache.flink.statefun.flink.core.httpfn.TransportClientSpec;
import org.apache.flink.statefun.flink.core.httpfn.UrlPathTemplate;
import org.apache.flink.statefun.sdk.FunctionType;

/** A Builder for RequestReply remote function type. */
public class RequestReplyFunctionBuilder {

  private final DefaultHttpRequestReplyClientSpec.Timeouts transportClientTimeoutsSpec =
      new DefaultHttpRequestReplyClientSpec.Timeouts();

  /**
   * Create a new builder for a remote function with a given type and an endpoint.
   *
   * @param functionType the function type that is served remotely.
   * @param endpoint the endpoint that serves that remote function.
   * @return a builder.
   */
  public static RequestReplyFunctionBuilder requestReplyFunctionBuilder(
      FunctionType functionType, URI endpoint) {
    return new RequestReplyFunctionBuilder(functionType, endpoint);
  }

  private final HttpFunctionEndpointSpec.Builder builder;

  private RequestReplyFunctionBuilder(FunctionType functionType, URI endpoint) {
    this.builder =
        HttpFunctionEndpointSpec.builder(
            TargetFunctions.functionType(functionType),
            new UrlPathTemplate(endpoint.toASCIIString()));
  }

  /**
   * Set a maximum request duration. This duration spans the complete call, including connecting to
   * the function endpoint, writing the request, function processing, and reading the response.
   *
   * @param duration the duration after which the request is considered failed.
   * @return this builder.
   */
  public RequestReplyFunctionBuilder withMaxRequestDuration(Duration duration) {
    transportClientTimeoutsSpec.setCallTimeout(duration);
    return this;
  }

  /**
   * Set a timeout for connecting to function endpoints.
   *
   * @param duration the duration after which a connect attempt is considered failed.
   * @return this builder.
   */
  public RequestReplyFunctionBuilder withConnectTimeout(Duration duration) {
    transportClientTimeoutsSpec.setConnectTimeout(duration);
    return this;
  }

  /**
   * Set a timeout for individual read IO operations during a function invocation request.
   *
   * @param duration the duration after which a read IO operation is considered failed.
   * @return this builder.
   */
  public RequestReplyFunctionBuilder withReadTimeout(Duration duration) {
    transportClientTimeoutsSpec.setReadTimeout(duration);
    return this;
  }

  /**
   * Set a timeout for individual write IO operations during a function invocation request.
   *
   * @param duration the duration after which a write IO operation is considered failed.
   * @return this builder.
   */
  public RequestReplyFunctionBuilder withWriteTimeout(Duration duration) {
    transportClientTimeoutsSpec.setWriteTimeout(duration);
    return this;
  }

  /**
   * Sets the max messages to batch together for a specific address.
   *
   * @param maxNumBatchRequests the maximum number of requests to batch for an address.
   * @return this builder.
   */
  public RequestReplyFunctionBuilder withMaxNumBatchRequests(int maxNumBatchRequests) {
    builder.withMaxNumBatchRequests(maxNumBatchRequests);
    return this;
  }

  @Internal
  HttpFunctionEndpointSpec spec() {
    final TransportClientSpec transportClientSpec =
        new TransportClientSpec(
            TransportClientConstants.OKHTTP_CLIENT_FACTORY_TYPE,
            transportClientPropertiesAsObjectNode(transportClientTimeoutsSpec));
    builder.withTransport(transportClientSpec);
    return builder.build();
  }

  private static ObjectNode transportClientPropertiesAsObjectNode(
      DefaultHttpRequestReplyClientSpec.Timeouts transportClientTimeoutsSpec) {
    final DefaultHttpRequestReplyClientSpec transportClientSpecPojo =
        new DefaultHttpRequestReplyClientSpec();
    transportClientSpecPojo.setTimeouts(transportClientTimeoutsSpec);

    return new ObjectMapper().valueToTree(transportClientSpecPojo);
  }
}