livy_rest.scala

// Start your Livy server: https://github.com/cloudera/livy#prerequisites

// First step is I instantiate a Spark Session and create a function that square in the spark shell and leave it open

val sparkSession = SparkSession.builder
    .master("local[1]")
    .appName("app_1")
    .getOrCreate()


def squareMe(n: Int): Double = {
  n*n 
}

---------------------------------------------------------------------------------------------------------------------------

// Now I need to grab this same session so I can use this function. I just go a GET / Sessions, and return that ID
// Since that's contingent on how many sessions you have open I've left that code out and just copied the ID here


import org.apache.http.client.methods.HttpPost
import org.apache.http.entity.StringEntity
import org.apache.http.impl.client.DefaultHttpClient
import org.apache.http.util.EntityUtils
import com.google.gson.Gson


val sessionId: Int = <My ID>


// From here we need to do a POST request with the number we want to square

val numbToSquare: Int = 2

val post = new HttpPost(s"http://localhost:8998/session/$sessionId/statements")

post.setHeader("Content-type", "application/json")

val body: String = s"""{'code': 'squareMe($numbToSquare)'}""" // JSON STRING of the code we want to run
val jsonBody = new Gson().toJson(body)
post.setEntity(new StringEntity(jsonBody))
post.setEntity(new StringEntity(body)) // Add our code to the body


val response = (new DefaultHttpClient).execute(post) // Execute our request
    
// Finally, print out the results 

val responseBody = EntityUtils.toString(response.getEntity)



println(responseBody)


{"id": 1,
 "output": {"data": {"text/plain":4.0},
             "execution_count": 1,
             "status": "ok"},
 "state": "available"}