Please clarify option --read-config-from-db

ts678 · February 20, 2020, 2:46pm

One can also right-click on a Duplicati shortcut, then Properties → Advanced, then check this box.

and then put up with manually answering a UAC prompt. The current installer seems to offer no assistance for this workaround, or Task Scheduler workaround, or installing as a service. In fact, subsequent install as a service works best with two .msi installer manual changes shown below:

This is one of my nominees for can-use-improvement-for-good-out-of-box-run-with-Admin-privileges.

But to get back to the original topic, Duplicati.GUI.TrayIcon.exe is presumably the explanation which doesn’t say quite enough, and there’s also not much talk in forum or GitHub issues – it’s uncommon:

--read-config-from-db
Set this option to read server connection info for running service from its database (only together with no-hosted-server).

--no-hosted-server
Set this option to not spawn a local service, use if the TrayIcon should connect to a running service.

On a default .msi install, TrayIcon contains its own Duplicati Server for the web browser to connect to, and which also does the backup and other operations. In a Windows service install, the server portion starts at boot time, and the TrayIcon at login time. TrayIcon then needs to connect to the server which sometimes means it may need a web UI password or certificate information so it can update its status.

The following code looks like --read-config-from-db connects to the configuration database to read info:

github.com

duplicati/duplicati/blob/94ea86b2845d0382db3c51a3a994bb5063b562a7/Duplicati/GUI/Duplicati.GUI.TrayIcon/Program.cs#L178-L200


      
          else if (Library.Utility.Utility.ParseBoolOption(options, READCONFIGFROMDB_OPTION))

          {

              databaseConnection = Server.Program.GetDatabaseConnection(options);

          

              if (databaseConnection != null)

              {

                  disableTrayIconLogin = databaseConnection.ApplicationSettings.DisableTrayIconLogin;

                  password = databaseConnection.ApplicationSettings.WebserverPasswordTrayIcon;

                  saltedpassword = false;

          

                  var cert = databaseConnection.ApplicationSettings.ServerSSLCertificate;

                  var scheme = "http";

          

                  if (cert != null && cert.HasPrivateKey)

                      scheme = "https";

          

                  serverURL = (new UriBuilder(serverURL)

                  {

                      Port = databaseConnection.ApplicationSettings.LastWebserverPort == -1 ? serverURL.Port : databaseConnection.ApplicationSettings.LastWebserverPort,

                      Scheme = scheme

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and sometimes this works, but sometimes its blocked by file access permissions to read the database.

EDIT:

Duplicati Tray Icon Silently Dies with --no-hosted-server arg #3137 gets into the permissions problem. Password or certificate on the server is not always used, but that might be the code that fetches them.

Reading configuration from the DB will have fewer permissions problems with non-default DB location which does not put it in SYSTEM account profile, and this also lets it survive Windows’ version update.