Open a web app from a sandbox

kumoba expose gives a port inside a sandbox a signed link that your browser can open. The link expires, and it works only for that sandbox and port.

Before you begin, install kumoba and start kumobad, and have a started sandbox in $id.

1. Start a server in the sandbox. Use setsid so it keeps running after the command returns:

   kumoba exec "$id" --user kumoba -- sh -c 'cd /workspace && setsid python3 -m http.server 8000 > /dev/null 2>&1 < /dev/null &'

2. Open it:

   kumoba expose "$id" --port 8000 --ttl-seconds 600 --open

The link lasts --ttl-seconds, up to an hour. Links are served on kumobad's preview listener, 127.0.0.1:7789 by default, which is a separate origin from the API so a page from the sandbox can't call it. Redirects from the app stay inside the link.

To share links beyond your machine, put a reverse proxy in front of the preview listener and set KUMOBAD_PREVIEW_URL to its public address. See Running as a service.