[SPARK-24646][CORE] Minor change to spark.yarn.dist.forceDownloadSchemes to support wildcard '*'

core/src/main/scala/org/apache/spark/deploy/SparkSubmit.scala

@@ -385,7 +385,7 @@ private[spark] class SparkSubmit extends Logging {
       val forceDownloadSchemes = sparkConf.get(FORCE_DOWNLOAD_SCHEMES)
 
       def shouldDownload(scheme: String): Boolean = {
-        forceDownloadSchemes.contains(scheme) ||
+        forceDownloadSchemes.contains("*") || forceDownloadSchemes.contains(scheme) ||
           Try { FileSystem.getFileSystemClass(scheme, hadoopConf) }.isFailure
       }
 
@@ -578,7 +578,8 @@ private[spark] class SparkSubmit extends Logging {
     }
     // Add the main application jar and any added jars to classpath in case YARN client
     // requires these jars.
-    // This assumes both primaryResource and user jars are local jars, otherwise it will not be
+    // This assumes both primaryResource and user jars are local jars, or already downloaded
+    // to local by configuring "spark.yarn.dist.forceDownloadSchemes", otherwise it will not be
     // added to the classpath of YARN client.
     if (isYarnCluster) {
       if (isUserJar(args.primaryResource)) {

core/src/main/scala/org/apache/spark/internal/config/package.scala

@@ -483,10 +483,11 @@ package object config {
 
   private[spark] val FORCE_DOWNLOAD_SCHEMES =
     ConfigBuilder("spark.yarn.dist.forceDownloadSchemes")
-      .doc("Comma-separated list of schemes for which files will be downloaded to the " +
+      .doc("Comma-separated list of schemes for which resources will be downloaded to the " +
         "local disk prior to being added to YARN's distributed cache. For use in cases " +
         "where the YARN service does not support schemes that are supported by Spark, like http, " +
-        "https and ftp.")
+        "https and ftp, or jars required to be in the local YARN client's classpath. Wildcard " +
+        "'*' is denoted to download resources for all the schemes.")
       .stringConf
       .toSequence
       .createWithDefault(Nil)

core/src/test/scala/org/apache/spark/deploy/SparkSubmitSuite.scala

@@ -995,20 +995,24 @@ class SparkSubmitSuite
   }
 
   test("download remote resource if it is not supported by yarn service") {
-    testRemoteResources(enableHttpFs = false, blacklistHttpFs = false)
+    testRemoteResources(enableHttpFs = false)
   }
 
   test("avoid downloading remote resource if it is supported by yarn service") {
-    testRemoteResources(enableHttpFs = true, blacklistHttpFs = false)
+    testRemoteResources(enableHttpFs = true)
   }
 
   test("force download from blacklisted schemes") {
-    testRemoteResources(enableHttpFs = true, blacklistHttpFs = true)
+    testRemoteResources(enableHttpFs = true, blacklistSchemes = Seq("http"))
+  }
+
+  test("force download for all the schemes") {
+    testRemoteResources(enableHttpFs = true, blacklistSchemes = Seq("*"))
   }
 
   private def testRemoteResources(
       enableHttpFs: Boolean,
-      blacklistHttpFs: Boolean): Unit = {
+      blacklistSchemes: Seq[String] = Nil): Unit = {
     val hadoopConf = new Configuration()
     updateConfWithFakeS3Fs(hadoopConf)
     if (enableHttpFs) {
@@ -1025,8 +1029,8 @@ class SparkSubmitSuite
     val tmpHttpJar = TestUtils.createJarWithFiles(Map("test.resource" -> "USER"), tmpDir)
     val tmpHttpJarPath = s"http://${new File(tmpHttpJar.toURI).getAbsolutePath}"
 
-    val forceDownloadArgs = if (blacklistHttpFs) {
-      Seq("--conf", "spark.yarn.dist.forceDownloadSchemes=http")
+    val forceDownloadArgs = if (blacklistSchemes.nonEmpty) {
+      Seq("--conf", s"spark.yarn.dist.forceDownloadSchemes=${blacklistSchemes.mkString(",")}")
     } else {
       Nil
     }
@@ -1044,14 +1048,19 @@ class SparkSubmitSuite
 
     val jars = conf.get("spark.yarn.dist.jars").split(",").toSet
 
-    // The URI of remote S3 resource should still be remote.
-    assert(jars.contains(tmpS3JarPath))
+    def isSchemeBlacklisted(scheme: String) = {
+      blacklistSchemes.contains("*") || blacklistSchemes.contains(scheme)
+    }
+
+    if (!isSchemeBlacklisted("s3")) {
+      assert(jars.contains(tmpS3JarPath))
+    }
 
-    if (enableHttpFs && !blacklistHttpFs) {
+    if (enableHttpFs && blacklistSchemes.isEmpty) {
       // If Http FS is supported by yarn service, the URI of remote http resource should
       // still be remote.
       assert(jars.contains(tmpHttpJarPath))
-    } else {
+    } else if (!enableHttpFs || isSchemeBlacklisted("http")) {
       // If Http FS is not supported by yarn service, or http scheme is configured to be force
       // downloading, the URI of remote http resource should be changed to a local one.
       val jarName = new File(tmpHttpJar.toURI).getName

docs/running-on-yarn.md

@@ -218,9 +218,10 @@ To use a custom metrics.properties for the application master and executors, upd
   <td><code>spark.yarn.dist.forceDownloadSchemes</code></td>
   <td><code>(none)</code></td>
   <td>
-    Comma-separated list of schemes for which files will be downloaded to the local disk prior to
+    Comma-separated list of schemes for which resources will be downloaded to the local disk prior to
     being added to YARN's distributed cache. For use in cases where the YARN service does not
-    support schemes that are supported by Spark, like http, https and ftp.
+    support schemes that are supported by Spark, like http, https and ftp, or jars required to be in the
+    local YARN client's classpath. Wildcard '*' is denoted to download resources for all the schemes.
   </td>
 </tr>
 <tr>