grpc-swift/Performance/QPSBenchmark/Sources/QPSBenchmark/Runtime/AsyncUnaryRequestMaker.swift

/*
 * Copyright 2020, gRPC Authors All rights reserved.
 *
 * 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.
 */

import GRPC
import Logging
import NIO

/// Makes unary requests to the server and records performance statistics.
final class AsyncUnaryRequestMaker: RequestMaker {
  private let client: Grpc_Testing_BenchmarkServiceClient
  private let requestMessage: Grpc_Testing_SimpleRequest
  private let logger: Logger
  private let stats: StatsWithLock

  /// Initialiser to gather requirements.
  /// - Parameters:
  ///    - config: config from the driver describing what to do.
  ///    - client: client interface to the server.
  ///    - requestMessage: Pre-made request message to use possibly repeatedly.
  ///    - logger: Where to log useful diagnostics.
  ///    - stats: Where to record statistics on latency.
  init(config: Grpc_Testing_ClientConfig,
       client: Grpc_Testing_BenchmarkServiceClient,
       requestMessage: Grpc_Testing_SimpleRequest,
       logger: Logger,
       stats: StatsWithLock) {
    self.client = client
    self.requestMessage = requestMessage
    self.logger = logger
    self.stats = stats
  }

  /// Initiate a request sequence to the server - in this case a single unary requests and wait for a response.
  /// - returns: A future which completes when the request-response sequence is complete.
  func makeRequest() -> EventLoopFuture<GRPCStatus> {
    let startTime = grpcTimeNow()
    let result = self.client.unaryCall(self.requestMessage)
    // Log latency stats on completion.
    result.status.whenSuccess { status in
      if status.isOk {
        let endTime = grpcTimeNow()
        self.stats.add(latency: endTime - startTime)
      } else {
        self.logger.error(
          "Bad status from unary request",
          metadata: ["status": "\(status)"]
        )
      }
    }
    return result.status
  }

  /// Request termination of the request-response sequence.
  func requestStop() {
    // No action here - we could potentially try and cancel the request easiest to just wait.
  }
}