sandbox-server for trycoding.io

The sandbox server allows clients to connect and establish a web socket connection to a sandboxed environment. The following image gives an overview of the system:

Install

1. Install sourcebox-sandbox (see INSTALL.md) for detailed instructions.
2. npm install https://github.com/waywaaard/sandbox-server
3. npm install -g pm2
4. By default the server starts on port 80. If you are using nginx you need to change that. It is possible to use a production.json configuration that is loaded when the production env is set. It gets automatically merged with the default configuration options.
5. Change the authentication secret and generate yourself a password for the local storage to access ("use") the test page (see below for further instructions)

Start Server

Start the server with: sudo pm2 start process.json --env production

Debugging

Start the server with sudo DEBUG=sourcebox:* pm2 start process.json --env production to get all the debug outputs on the console.

Show Resource Usage Information

You can use systemd-cgtop to watch the current created sandboxes and their resource usage.

Testpage

The sandbox server serves a simple testpage on port 80. See options. You can disable the testpage by setting serverStatic: false. In order to access the server you need to generate yourself a valid password token and set it on your local storage.

Example password in the browser console:

localStorage.password = "eyJhbGciOiJIUzI1NiJ9.ZGlkaXRmb3J0aGVsdWx6.CMb8-OxIFLoXfTwdT21fqIVlqIA7jfeklLgiwu2xUHg"

Use the jsonwebtoken package and create yourself a token by jwt.sign(PW, SECRET) and use the above line to set it in your browser. You may use https://runkit.com/npm/jsonwebtoken as a fast way of creating one.

Troubleshooting

If the test server fails with and internal error due to failed to set cgroup memory limit, then you need to follow these steps:

1. Add cgroup_enable=memory swapaccount=1 to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub
2. Run update-grub
3. Reboot the server
4. Restart/Start server and try again