piping into kamal exec does not work

[prullmann]

When trying to pipe data into commands executed in containers using kamal exec, no data is recieved.

Use Case:

I am trying to restore a database backup via the following command from my dev machine:
kamal accessory exec -i --reuse mysql 'mysql example_db"' < example_db_backup.sql
(ignoring password handling for this example)

Kamal translates this to:
ssh -t example_host docker exec -it example_project-mysql 'mysql example_db' < example_db_backup.sql

However, to make piping through docker work, -i has to be set, but not -t.

Proposed Solution:

I suggest that besides the --interactive/-i flag, a --tty/-t flag is added to control both independently.

Alternative Solution:
Kamal could also check if STDIN is attached to a file/pipe when interactive is enabled and set -i instead of -ti in this case.

If one of those solutions sound acceptable, I am happy to write a PR.

[djmb]

For backword compatibility I think we should stick to -it by default. But I think using -i when attached to a file or pipe makes sense.