Merge pull request #54 from StuartFerguson/task/#51_addretryclass

Added retry class

Author: StuartFerguson

Shared.IntegrationTesting/Retry.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Shared.IntegrationTesting
+{
+    using System.Threading;
+    using System.Threading.Tasks;
+
+    public static class Retry
+    {
+        #region Fields
+
+        /// <summary>
+        /// The default retry for
+        /// </summary>
+        private static readonly TimeSpan DefaultRetryFor = TimeSpan.FromSeconds(60);
+
+        /// <summary>
+        /// The default retry interval
+        /// </summary>
+        private static readonly TimeSpan DefaultRetryInterval = TimeSpan.FromSeconds(5);
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Fors the specified action.
+        /// </summary>
+        /// <param name="action">The action.</param>
+        /// <param name="retryFor">The retry for.</param>
+        /// <param name="retryInterval">The retry interval.</param>
+        /// <returns></returns>
+        public static async Task For(Func<Task> action,
+                                     TimeSpan? retryFor = null,
+                                     TimeSpan? retryInterval = null)
+        {
+            DateTime startTime = DateTime.Now;
+            Exception lastException = null;
+
+            if (retryFor == null)
+            {
+                retryFor = Retry.DefaultRetryFor;
+            }
+
+            while (DateTime.Now.Subtract(startTime).TotalMilliseconds < retryFor.Value.TotalMilliseconds)
+            {
+                try
+                {
+                    await action().ConfigureAwait(false);
+                    lastException = null;
+                    break;
+                }
+                catch (Exception e)
+                {
+                    lastException = e;
+
+                    // wait before retrying
+                    Thread.Sleep(retryInterval ?? Retry.DefaultRetryInterval);
+                }
+            }
+
+            if (lastException != null)
+            {
+                throw lastException;
+            }
+        }
+
+        #endregion
+    }
+}