How can I clone an entire remote directory tree and file structure but have empty files, via the command line?

Question

On a remote production server I have a directory that has more than 15 Terabytes of data. Also, in addition to Linux permission, ACLs are heavily used to allow departments, users, and daemons fine tuned access.

For our CI/CD pipeline and automated testing, I need to test how changes to these permissions affect the system, but before I can do that, I need a clone of what's on production in the test environment.

I obviously can't clone 15 Terabyte of data, and I really don't care about the data, I just care about the meta data (filenames, permissions, timestamps - basically all the info ls -lah returns.)

It's easy to see what I'm trying to do with how I'm using rsync:

rsync -aAr --include='*/' --exclude='*' [email protected]:/my/directory/ /test/directory/

This gives me exactly what I need from a directory standpoint. If rsync had an option to allow files to be copied over with 0 content but filenames and attributes intact, problem solved. (Does it?)

For now, after I run the above rsync command for the directories, here is how I'm approaching this.

ssh [email protected] 'find /my/directory -type f -exec ls -lah {} \;' > my.production.directory.files.txt

This gives me a local file where the contents contain lines of data like this:

-rwxrwxrwx  1 owner  group    15K Oct 13 10:07 /my/directory/jobs.txt

That has 9 fields, and I'm passing it to awk and bash:

cat my.production.directory.files.txt | awk '{print "touch " $9 " && chown "$3":"$4" "$9}' | bash

I feel like there has to be a better way. before I filter that file through other commands to apply chmod and the original timestamps, isn't there a more efficient way to do this? Something like cp has with --attributes-only like touch and chown can do with --reference, except against a remote file system?

Note, the answer must be executed directly on the command line. I cannot upload or rely on any scripts. Also, I know getfacl -R and setfacl will restore the permissions, but it does not restore timestamp and non-permissions related file data (that I'm aware.)

Answer 1

Here's a crazy idea: what if you use sshfs?

1. Mount the remote directory locally using sshfs:

   sshfs remoteuser@remotehost:/my/directory /mountpoint
   

2. Use the --attributes-only option to cp to recreate the file structure:

   cp -a --attributes-only /mountpoint /test/directory
   

3. Unmount the sshfs filesystem:

   fusermount -u /mountpoint
   

This doesn't require installing any additional software on the remote host.