Parallel Csv Generation

Author: baileydauterman

src/Faker.NET/Files/Csv/CsvFaker.cs

@@ -1,4 +1,5 @@
-using Faker.NET.Attributes;
+using System.Collections.Concurrent;
+using Faker.NET.Attributes;
 
 namespace Faker.NET.Files.Csv
 {
@@ -161,6 +162,22 @@ public IEnumerable<string> Generate()
             }
         }
 
+        public string[] GenerateParallel(int batchSize = 1000)
+        {
+            var arr = new string[_rowsCountToGenerate];
+            arr[0] = JoinColumns(_headers.Keys);
+
+            Parallel.ForEach(Partitioner.Create(1, arr.Length, batchSize), range =>
+            {
+                for (int i = range.Item1; i < range.Item2; i++)
+                {
+                    arr[i] = GenerateRow();
+                }
+            });
+
+            return arr;
+        }
+
         /// <summary>
         /// Outputs the data to the <see cref="BaseStream"/>.
         /// Writes to a <see cref="MemoryStream"/> if a file is not given.

tests/Faker.NET.Tests/Files/Csv.cs

@@ -33,9 +33,20 @@ public void GenerateCsv()
         [TestCase(500_000)]
         public void GenerateMassiveRows(int rowCount)
         {
+            // more of a proof of concept rather than testing because Generate() returns an IEnumerable
+            // at time of writing will generate 3,000,000 values in about 2.5 seconds
             var faker = CreateCsvFaker().Iterations((uint)rowCount);
+            faker.Generate().ToArray();
+        }
 
-            faker.Generate();
+        [Test]
+        [TestCase(100_000)]
+        [TestCase(200_000)]
+        [TestCase(500_000)]
+        public void GenerateParallelMassiveRows(int rowCount)
+        {
+            var faker = CreateCsvFaker().Iterations((uint)rowCount);
+            faker.GenerateParallel();
         }
 
         [Test]