Writing an rsync shell script on Mac to continuously sync local directory with remote web server

Question

I need to set up a shell script on Mac OS X Mountain Lion to sync a local directory to a remote directory (web server) using either an SSH connection (tunnel) or SFTP and have it run continuously every 30 seconds.

I also need to exclude certain files or folders from being synced.

The syncing would be unidirectional (mac -> webserver).

The basic parameters I need to have implemented are as follows:

Local path: /Volumes/path/to/local/directory
Remote server: example.com
username: someUser
password: somePassword
Remote path: /path/from/server/root/to/htdocs
Files to exclude: '.ht*', '*.sublime-*'
Folders to exclude: 'cache','administrator/cache'

I would also need help writing the crontask and adding it to my system to execute automatically.

Any help would be greatly appreciated.

Answer 1

Here's what I would do:

First, test that you can use ssh (login with user name and password):

$ ssh example.com
^D

Create an SSH key:

$ ssh-keygen

(don't enter a password)

This will create the ~/.ssh/id_rsa (private key) and ~/.ssh/id_rsa.pub (public key files)

You'll need to transer the public key (id_rsa.pub) to your remote server (example.com) and then on the remote server, do the following:

$ cat id_rsa.pub >> ~/.ssh/authorized_keys
$ rm id_rsa.pub
^D

This adds the public key to the set of authorised keys.

You'll now be able to use ssh to connect to your remote server without having to use a username and password.

Next would be to use the rsync command, the following should suffice:

$ rsync -avz -e ssh 
     --exclude '*.ht*' --exclude '*.sublime-*' --exclude 'cache/' 
     --exclude 'administrator/cache'
     [email protected]:/directory/on/server /directory/on/local

(should be all on one line)

Now, once you've satisfied that this works for you, you want to put that command into a shell script (rsync_script.sh)

Then, you can use launchctl to schedule it:

In ~/Library/LaunchAgents/, create com.example.rsync.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.example.rsync</string>
    <key>KeepAlive</key>
    <true/>
    <key>ProgramArguments</key>
    <array>
        <string>/bin/sh</string>
        <string>/path/to/rsync_script.sh</string>
    </array>
    <key>StartInterval</key>
    <integer>30</integer>
</dict>
</plist>

Couple of gotchas:

• Make sure that the rsync_script.sh is executable, i.e. do chmod 755 /path/to/the/rsync_script.sh
• Make sure that the user which created the SSH keys is the same user as sets up the launchd plist.