[LIVY-194][REPL] Add shared language support for Livy interactive ses…

…sion

This is a ongoing work. Putting it here to leverage travis to test.

In the current Livy when we create a new session we need to specify session kind, which represents the interpreter kind bound with this session. User could choose either `spark` or `pyspark` or `sparkr`, Livy internally will create a related interpreter with current session. Also in Livy each session represents a complete Spark application / SparkContext.

This brings a limitation that user can only choose one language along with its own Spark application. Furthermore, data generated by `pyspark` interpreter cannot be shared with `spark` interpreter. So to improve the usability of Livy we propose to add multiple interpreters support in one session.

Author: jerryshao <[email protected]>

Closes apache#28 from jerryshao/LIVY-194.

Change-Id: I743871c80ccb5c16101236e052d5f31662382667

client-common/src/main/java/org/apache/livy/client/common/HttpMessages.java

@@ -82,13 +82,15 @@ private SessionInfo() {
   public static class SerializedJob implements ClientMessage {
 
     public final byte[] job;
+    public final String jobType;
 
-    public SerializedJob(byte[] job) {
+    public SerializedJob(byte[] job, String jobType) {
       this.job = job;
+      this.jobType = jobType;
     }
 
     private SerializedJob() {
-      this(null);
+      this(null, null);
     }
 
   }

client-http/src/main/java/org/apache/livy/client/http/JobHandleImpl.java

@@ -138,7 +138,7 @@ void start(final String command, final ByteBuffer serializedJob) {
       @Override
       public void run() {
         try {
-          ClientMessage msg = new SerializedJob(BufferUtils.toByteArray(serializedJob));
+          ClientMessage msg = new SerializedJob(BufferUtils.toByteArray(serializedJob), "spark");
           JobStatus status = conn.post(msg, JobStatus.class, "/%d/%s", sessionId, command);
 
           if (isCancelPending) {

client-http/src/test/scala/org/apache/livy/client/http/HttpClientSpec.scala

@@ -217,7 +217,7 @@ class HttpClientSpec extends FunSpecLike with BeforeAndAfterAll with LivyBaseUni
 
   private def runJob(sync: Boolean, genStatusFn: Long => Seq[JobStatus]): (Long, JFuture[Int]) = {
     val jobId = java.lang.Long.valueOf(ID_GENERATOR.incrementAndGet())
-    when(session.submitJob(any(classOf[Array[Byte]]))).thenReturn(jobId)
+    when(session.submitJob(any(classOf[Array[Byte]]), anyString())).thenReturn(jobId)
 
     val statuses = genStatusFn(jobId)
     val first = statuses.head

core/src/main/scala/org/apache/livy/msgs.scala

@@ -28,7 +28,7 @@ case class Msg[T <: Content](msg_type: MsgType, content: T)
 
 sealed trait Content
 
-case class ExecuteRequest(code: String) extends Content {
+case class ExecuteRequest(code: String, kind: Option[String]) extends Content {
   val msg_type = MsgType.execute_request
 }
 

core/src/main/scala/org/apache/livy/sessions/Kind.scala

@@ -30,21 +30,21 @@ case class PySpark() extends Kind {
   override def toString: String = "pyspark"
 }
 
-case class PySpark3() extends Kind {
-  override def toString: String = "pyspark3"
-}
-
 case class SparkR() extends Kind {
   override def toString: String = "sparkr"
 }
 
+case class Shared() extends Kind {
+  override def toString: String = "shared"
+}
+
 object Kind {
 
   def apply(kind: String): Kind = kind match {
     case "spark" | "scala" => Spark()
     case "pyspark" | "python" => PySpark()
-    case "pyspark3" | "python3" => PySpark3()
     case "sparkr" | "r" => SparkR()
+    case "shared" => Shared()
     case other => throw new IllegalArgumentException(s"Invalid kind: $other")
   }
 

integration-test/pom.xml

@@ -286,7 +286,7 @@
         <configuration>
           <environmentVariables>
             <LIVY_HOME>${execution.root}</LIVY_HOME>
-            <LIVY_TEST>false</LIVY_TEST>
+            <LIVY_TEST>true</LIVY_TEST>
             <LIVY_INTEGRATION_TEST>true</LIVY_INTEGRATION_TEST>
           </environmentVariables>
           <systemProperties>

python-api/src/main/python/livy/client.py

@@ -70,6 +70,7 @@ def __init__(self, url, load_defaults=True, conf_dict=None):
         uri = urlparse(url)
         self._config = ConfigParser()
         self._load_config(load_defaults, conf_dict)
+        self._job_type = 'pyspark'
         match = re.match(r'(.*)/sessions/([0-9]+)', uri.path)
         if match:
             base = ParseResult(scheme=uri.scheme, netloc=uri.netloc,
@@ -395,7 +396,8 @@ def _reconnect_to_existing_session(self):
     def _send_job(self, command, job):
         pickled_job = cloudpickle.dumps(job)
         base64_pickled_job = base64.b64encode(pickled_job).decode('utf-8')
-        base64_pickled_job_data = {'job': base64_pickled_job}
+        base64_pickled_job_data = \
+            {'job': base64_pickled_job, 'jobType': self._job_type}
         handle = JobHandle(self._conn, self._session_id,
             self._executor)
         handle._start(command, base64_pickled_job_data)

repl/scala-2.10/src/main/scala/org/apache/livy/repl/SparkInterpreter.scala

@@ -26,20 +26,20 @@ import scala.tools.nsc.interpreter.JPrintWriter
 import scala.tools.nsc.interpreter.Results.Result
 import scala.util.{Failure, Success, Try}
 
-import org.apache.spark.{SparkConf, SparkContext}
+import org.apache.spark.SparkConf
 import org.apache.spark.repl.SparkIMain
 
+import org.apache.livy.rsc.driver.SparkEntries
+
 /**
  * This represents a Spark interpreter. It is not thread safe.
  */
-class SparkInterpreter(conf: SparkConf)
-  extends AbstractSparkInterpreter with SparkContextInitializer {
+class SparkInterpreter(protected override val conf: SparkConf) extends AbstractSparkInterpreter {
 
   private var sparkIMain: SparkIMain = _
-  protected var sparkContext: SparkContext = _
 
-  override def start(): SparkContext = {
-    require(sparkIMain == null && sparkContext == null)
+  override def start(): Unit = {
+    require(sparkIMain == null)
 
     val settings = new Settings()
     settings.embeddedDefaults(Thread.currentThread().getContextClassLoader())
@@ -103,23 +103,21 @@ class SparkInterpreter(conf: SparkConf)
         }
       }
 
-      createSparkContext(conf)
+      postStart()
     }
-
-    sparkContext
   }
 
-  protected def bind(name: String, tpe: String, value: Object, modifier: List[String]): Unit = {
+  override protected def bind(name: String,
+      tpe: String,
+      value: Object,
+      modifier: List[String]): Unit = {
     sparkIMain.beQuietDuring {
       sparkIMain.bind(name, tpe, value, modifier)
     }
   }
 
   override def close(): Unit = synchronized {
-    if (sparkContext != null) {
-      sparkContext.stop()
-      sparkContext = null
-    }
+    super.close()
 
     if (sparkIMain != null) {
       sparkIMain.close()
@@ -128,7 +126,7 @@ class SparkInterpreter(conf: SparkConf)
   }
 
   override protected def isStarted(): Boolean = {
-    sparkContext != null && sparkIMain != null
+    sparkIMain != null
   }
 
   override protected def interpret(code: String): Result = {

repl/scala-2.11/src/main/scala/org/apache/livy/repl/SparkInterpreter.scala

@@ -26,20 +26,20 @@ import scala.tools.nsc.interpreter.JPrintWriter
 import scala.tools.nsc.interpreter.Results.Result
 import scala.util.control.NonFatal
 
-import org.apache.spark.{SparkConf, SparkContext}
+import org.apache.spark.SparkConf
 import org.apache.spark.repl.SparkILoop
 
+import org.apache.livy.rsc.driver.SparkEntries
+
 /**
  * Scala 2.11 version of SparkInterpreter
  */
-class SparkInterpreter(conf: SparkConf)
-  extends AbstractSparkInterpreter with SparkContextInitializer {
+class SparkInterpreter(protected override val conf: SparkConf) extends AbstractSparkInterpreter {
 
-  protected var sparkContext: SparkContext = _
   private var sparkILoop: SparkILoop = _
   private var sparkHttpServer: Object = _
 
-  override def start(): SparkContext = {
+  override def start(): Unit = {
     require(sparkILoop == null)
 
     val rootDir = conf.get("spark.repl.classdir", System.getProperty("java.io.tmpdir"))
@@ -89,17 +89,12 @@ class SparkInterpreter(conf: SparkConf)
         }
       }
 
-      createSparkContext(conf)
+      postStart()
     }
-
-    sparkContext
   }
 
   override def close(): Unit = synchronized {
-    if (sparkContext != null) {
-      sparkContext.stop()
-      sparkContext = null
-    }
+    super.close()
 
     if (sparkILoop != null) {
       sparkILoop.closeInterpreter()
@@ -115,7 +110,7 @@ class SparkInterpreter(conf: SparkConf)
   }
 
   override protected def isStarted(): Boolean = {
-    sparkContext != null && sparkILoop != null
+    sparkILoop != null
   }
 
   override protected def interpret(code: String): Result = {
@@ -127,7 +122,10 @@ class SparkInterpreter(conf: SparkConf)
     Option(sparkILoop.lastRequest.lineRep.call("$result"))
   }
 
-  protected def bind(name: String, tpe: String, value: Object, modifier: List[String]): Unit = {
+  override protected def bind(name: String,
+      tpe: String,
+      value: Object,
+      modifier: List[String]): Unit = {
     sparkILoop.beQuietDuring {
       sparkILoop.bind(name, tpe, value, modifier)
     }

repl/src/main/resources/fake_shell.py

@@ -531,14 +531,42 @@ def main():
         listening_port = 0
         if os.environ.get("LIVY_TEST") != "true":
             #Load spark into the context
-            exec('from pyspark.shell import sc', global_dict)
-            exec('from pyspark.shell import sqlContext', global_dict)
             exec('from pyspark.sql import HiveContext', global_dict)
             exec('from pyspark.streaming import StreamingContext', global_dict)
             exec('import pyspark.cloudpickle as cloudpickle', global_dict)
 
+            from py4j.java_gateway import java_import, JavaGateway, GatewayClient
+            from pyspark.conf import SparkConf
+            from pyspark.context import SparkContext
+            from pyspark.sql import SQLContext, HiveContext, Row
+            # Connect to the gateway
+            gateway_port = int(os.environ["PYSPARK_GATEWAY_PORT"])
+            gateway = JavaGateway(GatewayClient(port=gateway_port), auto_convert=True)
+
+            # Import the classes used by PySpark
+            java_import(gateway.jvm, "org.apache.spark.SparkConf")
+            java_import(gateway.jvm, "org.apache.spark.api.java.*")
+            java_import(gateway.jvm, "org.apache.spark.api.python.*")
+            java_import(gateway.jvm, "org.apache.spark.mllib.api.python.*")
+            java_import(gateway.jvm, "org.apache.spark.sql.*")
+            java_import(gateway.jvm, "org.apache.spark.sql.hive.*")
+            java_import(gateway.jvm, "scala.Tuple2")
+
+            jsc = gateway.entry_point.sc()
+            jconf = gateway.entry_point.sc().getConf()
+            jsqlc = gateway.entry_point.hivectx() if gateway.entry_point.hivectx() is not None \
+                else gateway.entry_point.sqlctx()
+
+            conf = SparkConf(_jvm = gateway.jvm, _jconf = jconf)
+            sc = SparkContext(jsc=jsc, gateway=gateway, conf=conf)
+            global_dict['sc'] = sc
+            sqlc = SQLContext(sc, jsqlc)
+            global_dict['sqlContext'] = sqlc
+
             if spark_major_version >= "2":
-                exec('from pyspark.shell import spark', global_dict)
+                from pyspark.sql import SparkSession
+                spark_session = SparkSession(sc, gateway.entry_point.sparkSession())
+                global_dict['spark'] = spark_session
             else:
                 # LIVY-294, need to check whether HiveContext can work properly,
                 # fallback to SQLContext if HiveContext can not be initialized successfully.

repl/src/main/scala/org/apache/livy/repl/AbstractSparkInterpreter.scala

@@ -21,13 +21,15 @@ import java.io.ByteArrayOutputStream
 
 import scala.tools.nsc.interpreter.Results
 
+import org.apache.spark.SparkConf
 import org.apache.spark.rdd.RDD
 import org.json4s.DefaultFormats
 import org.json4s.Extraction
 import org.json4s.JsonAST._
 import org.json4s.JsonDSL._
 
 import org.apache.livy.Logging
+import org.apache.livy.rsc.driver.SparkEntries
 
 object AbstractSparkInterpreter {
   private[repl] val KEEP_NEWLINE_REGEX = """(?<=\n)""".r
@@ -41,6 +43,10 @@ abstract class AbstractSparkInterpreter extends Interpreter with Logging {
 
   protected val outputStream = new ByteArrayOutputStream()
 
+  protected var entries: SparkEntries = _
+
+  def sparkEntries(): SparkEntries = entries
+
   final def kind: String = "spark"
 
   protected def isStarted(): Boolean
@@ -49,6 +55,52 @@ abstract class AbstractSparkInterpreter extends Interpreter with Logging {
 
   protected def valueOfTerm(name: String): Option[Any]
 
+  protected def bind(name: String, tpe: String, value: Object, modifier: List[String]): Unit
+
+  protected def conf: SparkConf
+
+  protected def postStart(): Unit = {
+    entries = new SparkEntries(conf)
+
+    if (isSparkSessionPresent()) {
+      bind("spark",
+        sparkEntries.sparkSession().getClass.getCanonicalName,
+        sparkEntries.sparkSession(),
+        List("""@transient"""))
+      bind("sc", "org.apache.spark.SparkContext", sparkEntries.sc().sc, List("""@transient"""))
+
+      execute("import org.apache.spark.SparkContext._")
+      execute("import spark.implicits._")
+      execute("import spark.sql")
+      execute("import org.apache.spark.sql.functions._")
+    } else {
+      bind("sc", "org.apache.spark.SparkContext", sparkEntries.sc().sc, List("""@transient"""))
+      val sqlContext = Option(sparkEntries.hivectx()).getOrElse(sparkEntries.sqlctx())
+      bind("sqlContext", sqlContext.getClass.getCanonicalName, sqlContext, List("""@transient"""))
+
+      execute("import org.apache.spark.SparkContext._")
+      execute("import sqlContext.implicits._")
+      execute("import sqlContext.sql")
+      execute("import org.apache.spark.sql.functions._")
+    }
+  }
+
+  override def close(): Unit = {
+    if (entries != null) {
+      entries.stop()
+      entries = null
+    }
+  }
+
+  private def isSparkSessionPresent(): Boolean = {
+    try {
+      Class.forName("org.apache.spark.sql.SparkSession")
+      true
+    } catch {
+      case _: ClassNotFoundException | _: NoClassDefFoundError => false
+    }
+  }
+
   override protected[repl] def execute(code: String): Interpreter.ExecuteResponse =
     restoreContextClassLoader {
       require(isStarted())

repl/src/main/scala/org/apache/livy/repl/BypassPySparkJob.scala

@@ -19,16 +19,13 @@ package org.apache.livy.repl
 import java.nio.charset.StandardCharsets
 
 import org.apache.livy.{Job, JobContext}
+import org.apache.livy.sessions._
 
 class BypassPySparkJob(
     serializedJob: Array[Byte],
-    replDriver: ReplDriver) extends Job[Array[Byte]] {
+    pi: PythonInterpreter) extends Job[Array[Byte]] {
 
   override def call(jc: JobContext): Array[Byte] = {
-    val interpreter = replDriver.interpreter
-    require(interpreter != null && interpreter.isInstanceOf[PythonInterpreter])
-    val pi = interpreter.asInstanceOf[PythonInterpreter]
-
     val resultByteArray = pi.pysparkJobProcessor.processBypassJob(serializedJob)
     val resultString = new String(resultByteArray, StandardCharsets.UTF_8)
     if (resultString.startsWith("Client job error:")) {

repl/src/main/scala/org/apache/livy/repl/Interpreter.scala

@@ -17,7 +17,6 @@
 
 package org.apache.livy.repl
 
-import org.apache.spark.SparkContext
 import org.json4s.JObject
 
 object Interpreter {
@@ -38,10 +37,8 @@ trait Interpreter {
 
   /**
    * Start the Interpreter.
-   *
-   * @return A SparkContext
    */
-  def start(): SparkContext
+  def start(): Unit
 
   /**
    * Execute the code and return the result, it may