How to consume api rest passing flink stream as parameter and return this stream transformed

Question

I'm new in apache flink. I have one flink scala project that consume data from kafka cluster and I need to pass the stream result as parameter to consume api that return this stream transformed. Here is my code

class Testing {
  def main(args: Array[String]): Unit = {}
  def streamTest(): Unit = {
    val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment
    val properties = new Properties()
    properties.setProperty("bootstrap.servers", "test1.server.local:9092,test2.server.local:9092,test3.server.local:9092")
    val consumer_test = new FlinkKafkaConsumer[String]("topic_test", new SimpleStringSchema(), properties)
    consumer_test.setStartFromEarliest()
    val stream =  env.addSource(consumer_test).setParallelism(5)
    val api_test = "http://api-test.server.local/test/?msg=%s"
    // Here I need pass stream as parameter to api and return transformed stream
    env.execute()
  }   
}

Any Help ?

What do You mean by passing the stream result as parameter ? Do You just want to perform request to API with parameter that comes from the stream ?? Maybe You could provide an example ?? — Dominik Wosiński, Feb 09 '20 at 10:29
I used stream.flatMap calling the function to connect api rest with out: Collector[String] variable. Thanks — Miguel Angel Perez Garcia, Feb 27 '20 at 13:14

score 0 · Answer 1 · answered Feb 18 '20 at 11:35

0

You should use any http/rest library with which you are familiar and then use asyncIO.

answered Feb 18 '20 at 11:35

Arvid Heise

3,524
5
11

score 0 · Accepted Answer · answered Feb 27 '20 at 13:37

This is my final code. I hope that helps

class Testing extends Serializable{
  def main(args: Array[String]): Unit = {}
  def streamTest(): Unit = {
    val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment
    val properties = new Properties()
    properties.setProperty("bootstrap.servers", "test1.server.local:9092,test2.server.local:9092,test3.server.local:9092")
    val consumer_test = new FlinkKafkaConsumer[String]("topic_test", new SimpleStringSchema(), properties)
    consumer_test.setStartFromEarliest()
    val stream =  env.addSource(consumer_test)
    // Here I need pass stream as parameter to api and return transformed stream
    val result = stream.flatMap{
      (str, out: Collector[String]) =>
        val api_test = "http://api-test.server.local/test/?msg=%s"
        out.collect {
          getUrl(api_test.format(URLEncoder.encode(str, "UTF-8")))
        }        
    }    
    env.execute()
  }

  def getUrl(url: String): String = {
    val timeout = 5
    val config = RequestConfig.custom.setConnectTimeout(timeout * 1000).setConnectionRequestTimeout(timeout * 1000).setSocketTimeout(timeout * 1000).build
    val client: CloseableHttpClient = HttpClientBuilder.create.setDefaultRequestConfig(config).build
    val request = new HttpGet(url)
    val response = client.execute(request)
    val entity = response.getEntity
    val get_result = EntityUtils.toString(entity)
    get_result
  }     
}

How to consume api rest passing flink stream as parameter and return this stream transformed

2 Answers2