question. Reinitialization provide

[LazarenkoA]

hello. I have such a code

container.Provide(func(clientCfg *config.Ignite) database.Db {
		ignite, err := database.NewIgnite(ctx, clientCfg)
		if err != nil {
			logger.Error(fmt.Errorf("container provide error: %w", err))
			return nil
		} else {
			return ignite
		}
	})

if the database is not available at the time of initialization, further calls will return nil

container.Invoke(func(ignite database.Db) error {
      //....
})

is it possible to make it so that when an error occurs atabase.NewIgnite(ctx, clientCfg) the container didn't remember the response, but the code went to container.Provide again?

[sywhang]

The container can't just ignore nil as a completely irrelevant value because nil could still be a valid value for other types.

You could use value groups to do something similar to what you wanted to do.

type DBResult struct {
  dig.Out

  db database.Db `group:"db"`
}

     // somewhere in your code invokes this code many times
     container.Provide(func(clientCfg *config.Ignite) DBResult {
		ignite, err := database.NewIgnite(ctx, clientCfg)
		if err != nil {
			logger.Error(fmt.Errorf("container provide error: %w", err))
			return DBResult{
                           db: nil
                         }
		} else {
			return DBResult{ db: ignite }
		}
	})

You can then consume this as a list of Dbs that you can iterate and ignore nils:

type ServerParams struct {
  dig.In

  Dbs []database.Db `group:"db"`
}

dig.Invoke(StartServer)
func StartServer(p ServerParams) {
  // use p.Dbs to find the non-nil db.  
}