Implemented a list delay to work around the eventually consistent issue.

This fixes #1546

Duplicati/Library/Backend/AmazonCloudDrive/AmzCD.cs

@@ -28,8 +28,10 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
     {
         private const string AUTHID_OPTION = "authid";
         private const string LABELS_OPTION = "amzcd-labels";
+        private const string DELAY_OPTION = "amzcd-consistency-delay";
 
         private const string DEFAULT_LABELS = "duplicati,backup";
+        private const string DEFAULT_DELAY = "15s";
 
         private const int PAGE_SIZE = 200;
 
@@ -49,6 +51,8 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
         private OAuthHelper m_oauth;
         private Dictionary<string, string> m_filecache;
         private string m_userid;
+        private DateTime m_waitUntil;
+        private TimeSpan m_delayTimeSpan;
 
         public AmzCD()
         {
@@ -70,9 +74,18 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
             if (options.ContainsKey(LABELS_OPTION))
                 labels = options[LABELS_OPTION];
 
+            string delay = DEFAULT_DELAY;
+            if (options.ContainsKey(DELAY_OPTION))
+                delay = options[DELAY_OPTION];
+            
             if (!string.IsNullOrWhiteSpace(labels))
                 m_labels = labels.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
 
+            if (string.IsNullOrWhiteSpace(delay))
+                m_delayTimeSpan = new TimeSpan(0);
+            else
+                m_delayTimeSpan = Library.Utility.Timeparser.ParseTimeSpan(delay);
+
             m_oauth = new OAuthHelper(authid, this.ProtocolKey) { AutoAuthHeader = true };
             m_userid = authid.Split(new string[] {":"}, StringSplitOptions.RemoveEmptyEntries).First();
         }
@@ -225,6 +238,8 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
         #region IStreamingBackend implementation
         public void Put(string remotename, System.IO.Stream stream)
         {
+            m_waitUntil = DateTime.Now + m_delayTimeSpan;
+
             var overwrite = FileCache.ContainsKey(remotename);
             var fileid = overwrite ? m_filecache[remotename] : null;
 
@@ -277,6 +292,10 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
         #region IBackend implementation
         public List<IFileEntry> List()
         {
+            var wait = m_waitUntil - DateTime.Now;
+            if (wait.Ticks > 0)
+                System.Threading.Thread.Sleep(wait);
+
             var query = string.Format("{0}/nodes?filters=parents:{1}&limit={2}", MetadataUrl, Utility.Uri.UrlEncode(CurrentDirectory.ID), PAGE_SIZE);
             var res = new List<IFileEntry>();
             string nextToken = null;
@@ -337,6 +356,8 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
         {
             try
             {
+                m_waitUntil = DateTime.Now + m_delayTimeSpan;
+
                 using(m_oauth.GetResponse(string.Format("{0}/trash/{1}", MetadataUrl, GetFileID(remotename)), null, "PUT"))
                 {
                 }
@@ -378,6 +399,7 @@ namespace Duplicati.Library.Backend.AmazonCloudDrive
                 return new List<ICommandLineArgument>(new ICommandLineArgument[] {
                     new CommandLineArgument(AUTHID_OPTION, CommandLineArgument.ArgumentType.Password, Strings.AmzCD.AuthidShort, Strings.AmzCD.AuthidLong(OAuthHelper.OAUTH_LOGIN_URL("amzcd"))),
                     new CommandLineArgument(LABELS_OPTION, CommandLineArgument.ArgumentType.String, Strings.AmzCD.LabelsShort, Strings.AmzCD.LabelsLong, DEFAULT_LABELS),
+                    new CommandLineArgument(DELAY_OPTION, CommandLineArgument.ArgumentType.Timespan, Strings.AmzCD.DelayShort, Strings.AmzCD.DelayLong, DEFAULT_DELAY),
                 });
             }
         }

Duplicati/Library/Backend/AmazonCloudDrive/Strings.cs

@@ -28,6 +28,8 @@ namespace Duplicati.Library.Backend.Strings
         public static string LabelsShort { get { return LC.L(@"The labels to set"); } }
         public static string LabelsLong { get { return LC.L(@"Use this option to set labels on the files and folders created"); } }
         public static string MultipleEntries(string folder, string parent) { return LC.L(@"There is more than one item named ""{0}"" in the folder ""{1}"""); }
-    }
+        public static string DelayShort { get { return LC.L(@"The consistency delay"); } }
+        public static string DelayLong { get { return LC.L(@"Amazon Cloud drive needs a small delay for results to stay consistent."); } }
+            }
 }