How to include file in production mode for Play framework

Question

An overview of my environments: Mac OS Yosemite, Play framework 2.3.7, sbt 0.13.7, Intellij Idea 14, java 1.8.0_25

I tried to run a simple Spark program in Play framework, so I just create a Play 2 project in Intellij, and change some files as follows:

app/Controllers/Application.scala:

package controllers

import play.api._
import play.api.libs.iteratee.Enumerator
import play.api.mvc._

object Application extends Controller {

  def index = Action {
    Ok(views.html.index("Your new application is ready."))
  }

  def trySpark = Action {
    Ok.chunked(Enumerator(utils.TrySpark.runSpark))
  }

}

app/utils/TrySpark.scala:

package utils

import org.apache.spark.{SparkContext, SparkConf}

object TrySpark {
  def runSpark: String = {
    val conf = new SparkConf().setAppName("trySpark").setMaster("local[4]")
    val sc = new SparkContext(conf)
    val data = sc.textFile("public/data/array.txt")
    val array = data.map ( line => line.split(' ').map(_.toDouble) )
    val sum = array.first().reduce( (a, b) => a + b )
    return sum.toString
  }
}

public/data/array.txt:

1 2 3 4 5 6 7

conf/routes:

GET        /                    controllers.Application.index

GET        /spark               controllers.Application.trySpark

GET        /assets/*file        controllers.Assets.at(path="/public", file)

build.sbt:

name := "trySpark"

version := "1.0"

lazy val `tryspark` = (project in file(".")).enablePlugins(PlayScala)

scalaVersion := "2.10.4"

libraryDependencies ++= Seq( jdbc , anorm , cache , ws,
"org.apache.spark" % "spark-core_2.10" % "1.2.0")

unmanagedResourceDirectories in Test <+=  baseDirectory ( _ /"target/web/public/test" )  

I type activator run to run this app in development mode then type localhost:9000/spark in the browser, it shows result 28 as expected. However, when I want type activator start to run this app in production mode it shows the following error message:

[info] play - Application started (Prod)
[info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000
[error] application - 

! @6kik15fee - Internal server error, for (GET) [/spark] ->

play.api.Application$$anon$1: Execution exception[[InvalidInputException: Input path does not exist: file:/Path/to/my/project/target/universal/stage/public/data/array.txt]]
    at play.api.Application$class.handleError(Application.scala:296) ~[com.typesafe.play.play_2.10-2.3.7.jar:2.3.7]
    at play.api.DefaultApplication.handleError(Application.scala:402) [com.typesafe.play.play_2.10-2.3.7.jar:2.3.7]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:205) [com.typesafe.play.play_2.10-2.3.7.jar:2.3.7]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:202) [com.typesafe.play.play_2.10-2.3.7.jar:2.3.7]
    at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:33) [org.scala-lang.scala-library-2.10.4.jar:na]
Caused by: org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: file:/Path/to/my/project/target/universal/stage/public/data/array.txt
    at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:251) ~[org.apache.hadoop.hadoop-mapreduce-client-core-2.2.0.jar:na]
    at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:270) ~[org.apache.hadoop.hadoop-mapreduce-client-core-2.2.0.jar:na]
    at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:201) ~[org.apache.spark.spark-core_2.10-1.2.0.jar:1.2.0]
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:205) ~[org.apache.spark.spark-core_2.10-1.2.0.jar:1.2.0]
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:203) ~[org.apache.spark.spark-core_2.10-1.2.0.jar:1.2.0]

It seems that my array.txt file is not loaded in the production mode. How can solve this problem?

Answer 1

The problem here is that the public directory will not be available in your root project dir when you run in production. It is packaged as a jar (usually in STAGE_DIR/lib/PROJ_NAME-VERSION-assets.jar) so you will not be able to access them this way.

I can see two solutions here:

1) Place the file in the conf directory. This will work, but seems very dirty especially if you intend to use more data files;

2) Place those files in some directory and tell sbt to package it as well. You can keep using the public directory although it seems better to use a different dir especially if you would want to have many more files.

Supposing array.txt is placed in a dir named datafiles in your project root, you can add this to build.sbt:

mappings in Universal ++=
(baseDirectory.value / "datafiles" * "*" get) map
    (x => x -> ("datafiles/" + x.getName))

Don't forget to change the paths in your app code:

// (...)
val data = sc.textFile("datafiles/array.txt")

Then just do a clean and when you run either start, stage or dist those files will be available.