You can't do this without killing the node process, but I haven't found that really matters. What's actually more annoying is the browser refresh on the client, but there isn't much you can do about that.
First, let's assume the application is already running. We start our app via forever with a script like the one in my answer here. I'd show you my whole upgrade script but it contains all kinds of Edthena-specific stuff, so I'll outline the steps we take below:
Build a new bundle. We do this on the server itself, which avoids any missing fibers issues. The bundle file is written to /home/ubuntu/apps/edthena/edthena.tar.gz
.
We cd
into the /home/ubuntu/apps/edthena
directory and rm -rf bundle
. That will blow away the files used by the current running process. Because the server is still running in memory it will keep executing. However, this step is problematic if your app regularly does uncached disk operatons like reading from the private
directory after startup. We don't, and all of the static assets are served by nginx, so I feel safe in doing this. Alternatively, you can move the old bundle
directory to something like bundle.old
and it should work.
tar xzf edthena.tar.gz
cd bundle/programs/server && npm install
forever restart /home/ubuntu/apps/edthena/bundle/main.js
There really isn't any downtime with this approach - it just restarts the app in the same way it would if the server threw an exception. Forever also keeps the environment from your original script, so you don't need to specify your environment variables again.
Finally, you can have a look at the log files in your ~/.forever
directory. The exact path can be found via forever list
.