Na wait for rsync daemon

[nalbury-handy]

During start up, our team has been getting:

rsync error: error in rsync protocol data stream (code 12) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-52/rsync/io.c(453) [receiver=2.6.9]

In our testing we found that it took approx 2-4s for the sync container to not only be running, but for the rsync daemon to be listening on the desired port. The start_container method in rsync.rb seemed to handle most of these start delays with a sleep 3 but if the rsync daemon is still not available after 3s, the initial sync is attempted anyway, resulting in the above error.

The connection to the rsync daemon can be tested with the --dry-run flag. So I've attempted a health_check method that will use this call to wait until rsync is listening on the desired port and container IP.

This health_check method will wait until the rsync --dry-run... command returns a non empty string. It will only try 10times to prevent an infinite loop, and any issues syncing after that are handled normally by the sync method.

Thanks!

[EugenMayer]

that's a pretty good implementation and finding. let me review it roughly and merge it later on. very valuable, thanks!

[EugenMayer]

i think one of the issue here might be, that AFAIR sync_host_ip is nowdays optional : https://github.com/EugenMayer/docker-sync-boilerplate/blob/master/rsync/docker-sync.yml#L8

i see that we allow auto there but i cannot find where we potentially expand it. Did you try it with auto?

[nalbury-handy]

Yea in our config we don't explicitly set sync_host_ip and it defaulted to 127.0.0.1, which worked as expected.

[EugenMayer]

great thanks! Good to merge?

[nalbury-handy]

Yup, thanks!!!

[EugenMayer]

I have to thank! Thanks for the contribution.