chetanmeh commented on a change in pull request #3812: ContainerClient + akka http alternative to HttpUtils URL: https://github.com/apache/incubator-openwhisk/pull/3812#discussion_r202898249
########## File path: common/scala/src/main/scala/whisk/core/containerpool/ContainerClient.scala ########## @@ -0,0 +1,212 @@ +/* + * 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 whisk.core.containerpool + +import akka.actor.ActorSystem +import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport._ +import akka.http.scaladsl.marshalling.Marshal +import akka.http.scaladsl.model.HttpMethods +import akka.http.scaladsl.model.HttpRequest +import akka.http.scaladsl.model.HttpResponse +import akka.http.scaladsl.model.MessageEntity +import akka.http.scaladsl.model.StatusCodes +import akka.http.scaladsl.model.headers.Connection +import akka.http.scaladsl.unmarshalling.Unmarshal +import akka.stream.StreamTcpException +import akka.stream.scaladsl.Sink +import akka.stream.scaladsl.Source +import akka.util.ByteString +import scala.concurrent.Await +import scala.concurrent.ExecutionContext +import scala.concurrent.Future +import scala.concurrent.TimeoutException +import scala.concurrent.duration._ +import scala.util.Try +import spray.json._ +import whisk.common.Logging +import whisk.common.TransactionId +import whisk.core.entity.ActivationResponse.ContainerHttpError +import whisk.core.entity.ActivationResponse._ +import whisk.core.entity.ByteSize +import whisk.core.entity.size.SizeLong +import whisk.http.PoolingRestClient + +trait ContainerClient { + def close(): Unit + def post(endpoint: String, body: JsValue, retry: Boolean)( + implicit tid: TransactionId): Future[Either[ContainerHttpError, ContainerResponse]] + +} + +/** + * This HTTP client is used only in the invoker to communicate with the action container. + * It allows to POST a JSON object and receive JSON object back; that is the + * content type and the accept headers are both 'application/json. + * The reason we still use this class for the action container is a mysterious hang + * in the Akka http client where a future fails to properly timeout and we have not + * determined why that is. + * + * @param hostname the host name + * @param timeout the timeout in msecs to wait for a response + * @param maxResponse the maximum size in bytes the connection will accept + * @param queueSize once all connections are used, how big of queue to allow for additional requests + * @param retryInterval duration between retries for TCP connection errors + */ +protected class PoolingContainerClient( + hostname: String, + port: Int, + timeout: FiniteDuration, + maxResponse: ByteSize, + queueSize: Int, + retryInterval: FiniteDuration = 100.milliseconds)(implicit logging: Logging, as: ActorSystem) + extends PoolingRestClient("http", hostname, port, queueSize, timeout = Some(timeout)) + with ContainerClient + with AutoCloseable { + + def close() = shutdown() + + /** + * Posts to hostname/endpoint the given JSON object. + * Waits up to timeout before aborting on a good connection. + * If the endpoint is not ready, retry up to timeout. + * Every retry reduces the available timeout so that this method should not + * wait longer than the total timeout (within a small slack allowance). + * + * @param endpoint the path the api call relative to hostname + * @param body the JSON value to post (this is usually a JSON objecT) + * @param retry whether or not to retry on connection failure + * @return Left(Error Message) or Right(Status Code, Response as UTF-8 String) + */ + def post(endpoint: String, body: JsValue, retry: Boolean)( + implicit tid: TransactionId): Future[Either[ContainerHttpError, ContainerResponse]] = { + + //create the request + val req = Marshal(body).to[MessageEntity].map { b => + //DO NOT reuse the connection (in case of paused containers) + //For details on Connection: Close handling, see: + // - https://doc.akka.io/docs/akka-http/current/common/http-model.html#http-headers + // - http://github.com/akka/akka-http/tree/v10.1.3/akka-http-core/src/test/scala/akka/http/impl/engine/rendering/ResponseRendererSpec.scala#L470-L571 + HttpRequest(HttpMethods.POST, endpoint, entity = b).withHeaders(Connection("close")) + } + + retryingRequest(req, timeout, retry) + .flatMap(response => + response.entity.contentLengthOption match { + case Some(contentLength) if response.status != StatusCodes.NoContent => + if (contentLength <= maxResponse.toBytes) { + Unmarshal(response.entity.withSizeLimit(maxResponse.toBytes)).to[String].map { o => + Right(ContainerResponse(response.status.intValue, o, None)) + } + } else { + truncated(response.entity.dataBytes).map { s => + Right(ContainerResponse(response.status.intValue, s, Some(contentLength.B, maxResponse))) + } + } + case _ => + //handle missing Content-Length as NoResponseReceived + //also handle 204 as NoResponseReceived, for parity with HttpUtils client + Future { Left(NoResponseReceived()) } + }) + .recover { + case t: StreamTcpException => Left(Timeout(t)) + case t: TimeoutException => Left(Timeout(t)) + case t: Throwable => Left(ConnectionError(t)) + } + } + private def retryingRequest(req: Future[HttpRequest], + timeout: FiniteDuration, + retry: Boolean): Future[HttpResponse] = { + request(req).recoverWith { + case t: akka.stream.StreamTcpException if retry => + val newTimeout = timeout - retryInterval + if (newTimeout > Duration.Zero) { + akka.pattern.after(retryInterval, as.scheduler)(retryingRequest(req, newTimeout, retry)) + } else { + logging.warn(this, s"POST failed with $t - no retry because timeout exceeded.") + Future.failed(t) + } + case t => Future.failed(t) + } + } + + private def truncated(responseBytes: Source[ByteString, _], + previouslyCaptured: ByteString = ByteString.empty): Future[String] = { + responseBytes.prefixAndTail(1).runWith(Sink.head).flatMap { + case (Nil, tail) => + //ignore the tail (MUST CONSUME ENTIRE ENTITY!) + tail.runWith(Sink.ignore).map(_ => previouslyCaptured.utf8String) + case (Seq(prefix), tail) => + val truncatedResponse = previouslyCaptured ++ prefix + if (truncatedResponse.size < maxResponse.toBytes) { + truncated(tail, truncatedResponse) + } else { + //ignore the tail (MUST CONSUME ENTIRE ENTITY!) + //captured string MAY be larger than the max response, so take only maxResponse bytes to get the exact length + tail.runWith(Sink.ignore).map(_ => truncatedResponse.take(maxResponse.toBytes.toInt).utf8String) Review comment: Would it be safe to convert byte stream truncated at arbitrary boundary to be converted to string? `HttpUtils` also used same approach so behavior wise its compatible ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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