Question related to AIP-21:
"In case of transfer operators where two providers are involved, the transfer operators will be moved to "source" of the transfer. "

What will happen if FtpToXOperator will be added? This will add X as dependency to ftp provider.

What will happen if FtpToXOperator will be added? This will add X as dependency to ftp provider

This AIP has been updated several times, and while we keep all the historical votings, there are also some subsequent changes. So AIP is mostly kept as historical records and it contains several updates (there were several rounds of additional changes and votes after the original voting passed).

If you want to see final decisions made and current status of naming conventions just look here (I will update that information in the AIP-21 to direct people there):

https://github.com/apache/airflow/blob/master/CONTRIBUTING.rst#naming-conventions-for-provider-packages

First of all FTPToX will by default land in "X" not in FTP (that has reversed since the first AIP-21 voting). The main criteria we have when we decide is who is most interested (stakeholder) in maintaining specific provider (and assumption is that the "target" side cares more and has more stakes in getting the data).

So FTPtoS3 will go to Amazon, FTPToGCS will go to Google.

In case of FTP/HTTP/IMAP/SQLITE - those are "generic" providers that have no clear stakeholders behind, so even GCSToFTP will go to Google and S3ToFTP will go to Amazon, even if they re the "source", this is a case-by-case decision but in case of very generic operators, databases which are not run "as a service" only, this is rather clear which direction it should go.

@RosterIn - I hope that will make it clear :)

And the wording in "naming convention" is I think rather clear:

It is often debatable where to put transfer operators but we agreed to the following criteria:

• We use "maintainability" of the operators as the main criteria - so the transfer operator should be kept at the provider which has highest "interest" in the transfer operator
• For Cloud Providers or Service providers that usually means that the transfer operators should land at the "target" side of the transfer