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You can do many things with Ant, one of them is the ability to use tools like tar, gzip, FTP and scp for remote deployment. At work, we use a shell script on our servers to deploy our apps, and we are using rsync to send the applications to the server before calling the shell script. Would be great to actually do this in one step ? It's quite easy!.

First, you need to install JSch. We use the jsch-0.1.29 release, we didn't try a later release. Copy the JAR into /Developer/Java/Ant/lib/ (Mac OS X 10.4) or /usr/share/ant/lib/ (Mac OS X 10.5).

Next, you need to add this JAR to the Ant lib list inside Eclipse. Open Eclipse's preferences (Eclipse->Preferences), open the Tab triangle and click on Runtime. Select Ant Home Entries and click on Add External JARs... Browse up to /Developer/Java/Ant/lib/ and select jsch-0.X.XX.jar. The JAR should now be part of the list of JARs available for Ant.

Ok, now it's time to actually create a Ant task for deployment. You can add a property like this to build.properties:

servers.production=my.server.address

And you add this to your build.xml file.

<target depends="setProps,init.install,build.woapp" name="deployProduction">
  <echo message="Starting file transfer to ${user.name}@${servers.production}" />
  <exec dir="." executable="rsync" os="Mac OS X" failonerror="true">
    <arg value="-aog" />
    <arg value="-e ssh" />
    <arg value="${dest.dir}/${project.name}.woa" />
    <arg value="${user.name}@${servers.production}:~" />
   </exec>
   <sshexec command="myshellscriptfordeployment -d ${project.name}.woa" host="${servers.production}" keyfile="${user.home}/.ssh/id_rsa" passphrase="" username="${user.name}"/>
</target>

Wait a minute... Maybe Ant will complain because it can't send the password to the remote server. How to fix this ? By creating a SSH public key if you don't already have one.

First, check if you already have a public key on your computer:

$ ls -al ~/.ssh/id_rsa.pub
-rw-r--r--   1 monuser  monuser  230 Dec  5  2006 .ssh/id_rsa.pub

No id_rsa.pub file ? Create one:

$ ssh-keygen -t rsa

Now copy your SSH public key to your remote server:

$ scp ~/.ssh/id_rsa.pub mynuser@remoteserver:myuser.pub

and put your public key in the authorized_keys file:

remoteserver$ cat ~/monuser.pub >> ~/.ssh/authorized_keys

Now, next time that you login by SSH from your computer to the server, it will stop asking for a password and the Ant task will stop complaining. For added security, when you create your key, use a passphrase. Don't forget to put the passphrase into the sshexec task. Don't use the passphrase if you put the build.xml file in CVS or SVN, because your co-workers will see your passphrase and also they won't be able to use the sshexec task unless they use the same passphrase as you.