FileSystem extension skeleton

src/csharp/Extensions/Microsoft.Spark.Extensions.Delta.E2ETest/Microsoft.Spark.Extensions.Delta.E2ETest.csproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
-    <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>

src/csharp/Extensions/Microsoft.Spark.Extensions.DotNet.Interactive.UnitTest/Microsoft.Spark.Extensions.DotNet.Interactive.UnitTest.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <RootNamespace>Microsoft.Spark.Extensions.DotNet.Interactive.UnitTest</RootNamespace>
-    <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>

src/csharp/Extensions/Microsoft.Spark.Extensions.Hyperspace.E2ETest/Microsoft.Spark.Extensions.Hyperspace.E2ETest.csproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
-    <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>

src/csharp/Microsoft.Spark.E2ETest/Hadoop/FileSystemTests.cs

@@ -0,0 +1,56 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.IO;
+using Microsoft.Spark.Hadoop.Fs;
+using Microsoft.Spark.Sql;
+using Microsoft.Spark.UnitTest.TestUtils;
+using Xunit;
+
+namespace Microsoft.Spark.E2ETest.Hadoop
+{
+    [Collection("Spark E2E Tests")]
+    public class FileSystemTests
+    {
+        private readonly SparkSession _spark;
+
+        public FileSystemTests(SparkFixture fixture)
+        {
+            _spark = fixture.Spark;
+        }
+
+        /// <summary>
+        /// Test that methods return the expected signature.
+        /// </summary>
+        [Fact]
+        public void TestSignatures()
+        {
+            using var tempDirectory = new TemporaryDirectory();
+
+            using FileSystem fs = FileSystem.Get(_spark.SparkContext.HadoopConfiguration());
+
+            Assert.IsType<bool>(fs.Delete(tempDirectory.Path, true));
+        }
+
+        /// <summary>
+        /// Test that Delete() deletes the file.
+        /// </summary>
+        [Fact]
+        public void TestDelete()
+        {
+            using FileSystem fs = FileSystem.Get(_spark.SparkContext.HadoopConfiguration());
+
+            using var tempDirectory = new TemporaryDirectory();
+            string path = Path.Combine(tempDirectory.Path, "temp-table");
+            _spark.Range(25).Write().Format("parquet").Save(path);
+
+            Assert.True(Directory.Exists(path));
+
+            Assert.True(fs.Delete(path, true));
+            Assert.False(fs.Delete(path, true));
+
+            Assert.False(Directory.Exists(path));
+        }
+    }
+}

src/csharp/Microsoft.Spark.E2ETest/IpcTests/SparkContextTests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using Microsoft.Spark.Hadoop.Conf;
 using Microsoft.Spark.UnitTest.TestUtils;
 using Xunit;
 
@@ -42,6 +43,8 @@ public void TestSignaturesV2_3_X()
 
             using var tempDir = new TemporaryDirectory();
             sc.SetCheckpointDir(TestEnvironment.ResourceDirectory);
+
+            Assert.IsType<Configuration>(sc.HadoopConfiguration());
         }
     }
 }

src/csharp/Microsoft.Spark/Hadoop/Conf/Configuration.cs

@@ -0,0 +1,23 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Spark.Interop.Ipc;
+
+namespace Microsoft.Spark.Hadoop.Conf
+{
+    /// <summary>
+    /// Provides access to configuration parameters.
+    /// </summary>
+    public class Configuration : IJvmObjectReferenceProvider
+    {
+        private readonly JvmObjectReference _jvmObject;
+
+        internal Configuration(JvmObjectReference jvmObject)
+        {
+            _jvmObject = jvmObject;
+        }
+
+        JvmObjectReference IJvmObjectReferenceProvider.Reference => _jvmObject;
+    }
+}

src/csharp/Microsoft.Spark/Hadoop/Fs/FileSystem.cs

@@ -0,0 +1,60 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using Microsoft.Spark.Hadoop.Conf;
+using Microsoft.Spark.Interop;
+using Microsoft.Spark.Interop.Ipc;
+
+namespace Microsoft.Spark.Hadoop.Fs
+{
+    /// <summary>
+    /// A fairly generic filesystem. It may be implemented as a distributed filesystem, or as a "local" one
+    /// that reflects the locally-connected disk. The local version exists for small Hadoop instances and for
+    /// testing.
+    /// 
+    /// All user code that may potentially use the Hadoop Distributed File System should be written to use a
+    /// FileSystem object. The Hadoop DFS is a multi-machine system that appears as a single disk. It's
+    /// useful because of its fault tolerance and potentially very large capacity.
+    /// </summary>
+    public class FileSystem : IJvmObjectReferenceProvider, IDisposable
+    {
+        private readonly JvmObjectReference _jvmObject;
+
+        internal FileSystem(JvmObjectReference jvmObject)
+        {
+            _jvmObject = jvmObject;
+        }
+
+        JvmObjectReference IJvmObjectReferenceProvider.Reference => _jvmObject;
+
+        /// <summary>
+        /// Returns the configured <see cref="FileSystem"/>.
+        /// </summary>
+        /// <param name="conf">The configuration to use.</param>
+        /// <returns>The FileSystem.</returns>
+        public static FileSystem Get(Configuration conf) =>
+            new FileSystem((JvmObjectReference)SparkEnvironment.JvmBridge.CallStaticJavaMethod(
+                "org.apache.hadoop.fs.FileSystem",
+                "get",
+                conf));
+
+        /// <summary>
+        /// Delete a file.
+        /// </summary>
+        /// <param name="path">The path to delete.</param>
+        /// <param name="recursive">If path is a directory and set to true, the directory is deleted else
+        /// throws an exception. In case of a file the recursive can be set to either true or false.</param>
+        /// <returns>True if delete is successful else false.</returns>
+        public bool Delete(string path, bool recursive = true)
+        {
+            JvmObjectReference pathObject =
+                SparkEnvironment.JvmBridge.CallConstructor("org.apache.hadoop.fs.Path", path);
+
+            return (bool)_jvmObject.Invoke("delete", pathObject, recursive);
+        }
+
+        public void Dispose() => _jvmObject.Invoke("close");
+    }
+}

src/csharp/Microsoft.Spark/SparkContext.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Runtime.Serialization.Formatters.Binary;
+using Microsoft.Spark.Hadoop.Conf;
 using Microsoft.Spark.Interop.Ipc;
 using static Microsoft.Spark.Utils.CommandSerDe;
 
@@ -312,6 +313,13 @@ public Broadcast<T> Broadcast<T>(T value)
             return new Broadcast<T>(this, value);
         }
 
+        /// <summary>
+        /// A default Hadoop Configuration for the Hadoop code (e.g. file systems) that we reuse.
+        /// </summary>
+        /// <returns>The Hadoop Configuration.</returns>
+        public Configuration HadoopConfiguration() =>
+            new Configuration((JvmObjectReference)_jvmObject.Invoke("hadoopConfiguration"));
+
         /// <summary>
         /// Returns JVM object reference to JavaRDD object transformed
         /// from a Scala RDD object.