Updates

An install made by the installer updates itself from the web UI: System → Software update. Admin only.

What happens

1. Check for updates fetches the release manifest at update.manifest_url and offers the newest release newer than the running one, with its release notes.
2. Update downloads that release's wheel (verifying its SHA-256 from the manifest) and installs it into a fresh virtualenv, /opt/caelum/releases/<version>, next to the running release. The camera keeps capturing meanwhile; the install log streams into the page.
3. The new release is smoke-tested (import caelum.main in its own venv), then current is switched to it, previous to the release that was running, and caelum exits. systemd starts the new release — capture pauses for a few seconds.
4. Once the new release has run for a minute, it confirms itself healthy and removes releases other than current and previous.

If anything before the switch fails — download, checksum, pip, smoke test — the running release is never touched; the page shows the error.

Automatic rollback

If the new release does not stay up, systemd keeps restarting it, and the boot guard (/opt/caelum/bin/caelum-launch, a small shell script outside every release) counts those starts. On the fourth one it switches current back to previous and starts that instead. The System page then reports that the update was rolled back. No SSH needed.

Offline cameras

A camera without internet access can be updated by uploading the wheel file (caelum-<version>-py3-none-any.whl from a release) under Install a wheel file. The rest is identical. pip still needs to reach PyPI for any dependency that changed since the running release; dependencies already installed once come from the service account's pip cache.

Update channels and self-hosting

The manifest is a static JSON file:

{
  "releases": [
    {
      "version": "0.3.0",
      "wheel": "caelum-0.3.0-py3-none-any.whl",
      "sha256": "…",
      "notes": "…"
    }
  ]
}

wheel is resolved relative to the manifest's own URL. Hosting releases somewhere other than GitHub therefore means copying manifest.json and the wheel from a release onto any static web server, and setting:

{ "update": { "manifest_url": "https://example.org/caelum/stable/manifest.json" } }

Channels are just different URLs — …/stable/ for most cameras, …/beta/ for a test camera.

From the command line

Re-running the installer with a newer wheel upgrades into the same layout — useful over SSH, or if the web UI itself is unreachable:

curl -fsSL https://github.com/roman-dvorak/caelum/releases/latest/download/install.sh | sudo bash
# or a specific file
sudo bash install.sh --wheel caelum-0.3.0-py3-none-any.whl

To go back by hand:

cd /opt/caelum
sudo -u caelum ln -sfn "$(readlink previous)" current
sudo systemctl restart caelum

What is not updated

The apt packages underneath — Python itself, python3-picamera2, Redis — belong to the operating system and are updated with apt, not from here.