LTS Shared application hosting documentation

This guide is to help users that have a project on LTS shared application servers like python1/2, php1/2/3, or webapps2.  It is assumed that you already have a project on one of these servers and an account on the server.

You will need the following prerequisites:

• Basic familiarity with Linux command line tools
• Basic familiarity with git source control
• An SSH client
• Fluency in the programming language and framework used by your project (e. g. Python Flask, or PHP Zend/Laminas)
• Optionally a code editor or development environment.

To update your code:

• Clone its git repo down to your local environment
• When you're done working on your code, commit and push your changes to the git remote
• Connect to the application server where your project lives.  
  • For Python Flask projects, this will be python1.cc.lehigh.edu
  • For PHP projects, this will be php1.cc.lehigh.edu
  • For some PHP projects that can't be run in a highly-available environment split across multiple servers, this will be webapps2.cc.lehigh.edu
  • For all of them, your login credentials are your normal Lehigh username and password
• Change directory to your project's working directory
  • This will be /srv/<project_name>
  • This entire folder should be a git repository
• Do a "git pull" to pull down your changes
  • If it's a Python project on python1/2:
    • You only have to do this on python1 and it will appear on python2 as well because /srv is actually a network shared folder
    • There will be a .wsgi in the project folder, usually called <project_name>.wsgi, where the value of <project_name> is your project's name
      • To reload your application, run the command "touch project_name.wsgi"
  • If it's a PHP project on php1/2/3:
    • You have to pull the changes on all three servers - repeat the steps above to SSH to php2.cc.lehigh.edu and php3.cc.lehigh.edu, changing to the project folder and running a "git pull" on each
  • If it's a PHP project on webapps2, then you're done
  • On all the servers, the web server's error logs are in the file /var/log/apache2/error.log
    • If your application isn't working correctly, you can look for problems in this file to troubleshoot
    • You can view it with the "less" command or use "tail -f" to watch it live while you try something in your application 

Alternatively, if you'd rather edit your code in-place on the server, you can setup an editor like Visual Studio Code.  This  allows you to open files for editing with a friendly graphical interface through an SSH connection.  You can also use a terminal-based editor like emacs or vim in your SSH session if you are comfortable using those tools.  You will still want to commit and push your changes to a git remote though so it can be pulled elsewhere and for collaboration.

Helpful resources:

• Basic Linux command line tutorial
• LinkedIn Learning git tutorial - all Lehigh users have access.  Use your Lehigh email address as your username and you'll be sent to the Lehigh single sign-on page to login.
• Remote code editing using VS Code
• Python Flask tutorial
• SSH Command
• SCP Command
• SSH Keys
• Community supported python channel - #lts-python in lehigh-home.slack.com