Fix SqlUtils.WithRetry() to open a new connection if the last attempt…

… closed the connection due to network issues. (#221)

Co-authored-by: RAMAKANT BHANDARU <rbhandaru@mtb.com>

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Changelog
 
-## v1.3.0 (Unreleased)
+## v1.3.1 (Unreleased)
+
+### Updates
+
+* Fix SQL retry logic to open a new connection if a previous failure closed the connection ([#221](https://github.com/microsoft/durabletask-mssql/pull/221)) - contributed by [@microrama](https://github.com/microrama)
+
+## v1.3.0
 
 ### Updates
 

src/DurableTask.SqlServer/SqlUtils.cs

@@ -29,7 +29,7 @@ static class SqlUtils
         {
             return reader.IsDBNull(columnIndex) ? null : reader.GetString(columnIndex);
         }
-        
+
         public static TaskMessage GetTaskMessage(this DbDataReader reader)
         {
             return new TaskMessage
@@ -560,7 +560,7 @@ static IEnumerable<SqlDataRecord> GetInstanceIdRecords(IEnumerable<string> insta
             var context = new SprocExecutionContext();
             try
             {
-                return await WithRetry(() => executor(command), context, traceHelper, instanceId);
+                return await WithRetry(command, executor, context, traceHelper, instanceId);
             }
             finally
             {
@@ -610,15 +610,20 @@ public static DateTime ToSqlUtcDateTime(this DateTime dateTime, DateTime default
             }
         }
 
-        static async Task<T> WithRetry<T>(Func<Task<T>> func, SprocExecutionContext context, LogHelper traceHelper, string? instanceId, int maxRetries = 5)
+        static async Task<T> WithRetry<T>(DbCommand command, Func<DbCommand, Task<T>> executor, SprocExecutionContext context, LogHelper traceHelper, string? instanceId, int maxRetries = 5)
         {
             context.RetryCount = 0;
 
             while (true)
             {
                 try
                 {
-                    return await func();
+                    // Open connection if network blip caused it to close on a previous attempt
+                    if (command.Connection.State != ConnectionState.Open)
+                    {
+                        await command.Connection.OpenAsync();
+                    }
+                    return await executor(command);
                 }
                 catch (Exception e)
                 {