feat: publish Imager OS list and launchers

.github/workflows/build-image.yml

@@ -35,11 +35,33 @@ jobs:
       - name: Build image
         run: sudo -E ./build-image.sh
 
-      - name: Publish latest Release
+      - name: Publish image + Imager OS list
         env:
           GH_TOKEN: ${{ github.token }}
         run: |
+          set -euo pipefail
+          . .build/image-meta.env
           TAG="dpea-pi-$(date +%Y%m%d-%H%M)"
-          gh release create "$TAG" .build/*.img.xz \
+          IMG_URL="/${GITHUB_REPOSITORY}/releases/download/${TAG}/${IMG_FILE}"
+          # os-list.json = a Raspberry Pi Imager repo with one entry. init_format
+          # enables the Customisation panel; the constant asset name means
+          # .../releases/latest/download/os-list.json is a stable URL for Imager.
+          jq -n \
+            --arg url "$IMG_URL" \
+            --arg date "$(date +%Y-%m-%d)" \
+            --arg sha "$EXTRACT_SHA256" \
+            --argjson esize "$EXTRACT_SIZE" \
+            --argjson dsize "$IMAGE_DOWNLOAD_SIZE" \
+            '{os_list: [ {
+               name: "DPEA Pi",
+               description: "DPEA exhibit base image (Raspberry Pi OS Trixie 64-bit + DPEA config)",
+               url: $url,
+               release_date: $date,
+               init_format: "systemd",
+               extract_size: $esize,
+               extract_sha256: $sha,
+               image_download_size: $dsize
+             } ] }' > .build/os-list.json
+          gh release create "$TAG" ".build/${IMG_FILE}" .build/os-list.json \
             --repo "$GITHUB_REPOSITORY" --title "$TAG" \
             --notes "Auto-built DPEA Pi image from ${GITHUB_SHA::7}" --latest

.gitignore

@@ -1 +1,2 @@
 .build/
+.idea/

README.md

@@ -42,9 +42,23 @@ demand, then publishes the result as this repo's latest Release. It runs
 `build-image.sh`, which customizes the stock Raspberry Pi OS image: download,
 grow, loop-mount, run `customize.sh` in a chroot (packages, avahi, uv, config),
 recompress. It runs on a native arm64 runner (free while this repo is public), so
-the chroot's arm64 binaries run natively. No default user is baked. Set user +
-hostname + wifi in the Imager at flash time. Pin `BASE_URL` in `build-image.sh` to
-a specific Raspberry Pi OS release for reproducibility.
+the chroot's arm64 binaries run natively. No default user is baked. Pin `BASE_URL`
+in `build-image.sh` to a specific Raspberry Pi OS release for reproducibility.
+
+The same job also publishes `os-list.json` (a Raspberry Pi Imager OS list) to the
+release, so it is served at a stable URL:
+`https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json`.
+
+## Flashing
+
+Launch Imager pointed at that OS list so "DPEA Pi" appears with the Customisation
+panel enabled (hostname, SSH, user, wifi):
+```
+rpi-imager --repo https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json
+```
+`imager-launchers/` has double-click wrappers of that command for macOS / Windows
+/ Linux, meant to be handed to students (e.g. from the student setup repo). The
+repo is public, so no GitHub account is needed to download the image.
 
 ## Testing
 
@@ -78,7 +92,8 @@ you can reach `172.17.21.2`.
 | `provision.sh`                      | apply the same config to an already-running Pi (no reflash)                  |
 | `lib/common.sh`                     | shared shell helpers for `provision.sh`                                      |
 | `hardware-smoke-test.sh`            | on-Pi smoke test of the baked config                                         |
-| `.github/workflows/build-image.yml` | build + publish the image                                                    |
+| `imager-launchers/`                 | double-click launchers that open Imager with the DPEA OS list                |
+| `.github/workflows/build-image.yml` | build + publish the image + `os-list.json`                                   |
 | `.github/workflows/validate.yml`    | PR checks (shellcheck + container validation)                                |
 
 The patched avahi `.deb` lives in the `avahi_0.8` repo, not here.

build-image.sh

@@ -63,5 +63,18 @@ rm -f "$MNT/tmp/customize.sh"
 
 # --- unmount (via trap) + compress ---
 cleanup; trap - EXIT
+
+# Record metadata for the Raspberry Pi Imager OS list (os-list.json, built by CI):
+# the sha256 + size are of the UNCOMPRESSED image, which Imager verifies.
+EXTRACT_SIZE="$(stat -c%s "$OUT_IMG")"
+EXTRACT_SHA256="$(sha256sum "$OUT_IMG" | awk '{print $1}')"
 xz -T0 -f "$OUT_IMG"
+{
+	echo "IMG_FILE=$(basename "${OUT_IMG}.xz")"
+	echo "EXTRACT_SIZE=${EXTRACT_SIZE}"
+	echo "EXTRACT_SHA256=${EXTRACT_SHA256}"
+	echo "IMAGE_DOWNLOAD_SIZE=$(stat -c%s "${OUT_IMG}.xz")"
+} > "$WORK/image-meta.env"
+
 echo "Image: ${OUT_IMG}.xz"
+echo "Meta:  $WORK/image-meta.env"

imager-launchers/README.md

@@ -0,0 +1,15 @@
+# Imager launchers
+
+Each launcher opens Raspberry Pi Imager preloaded with the DPEA OS list
+(`--repo https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json`),
+so "DPEA Pi" appears in the OS list with the **Customisation** panel enabled
+(hostname, SSH, user, wifi). Plain "Use custom" on a local file cannot do that.
+
+- `dpea-pi-imager.command` - macOS (double-click; may need `chmod +x` once, and
+  right-click -> Open the first time to clear Gatekeeper).
+- `dpea-pi-imager.bat` - Windows (double-click).
+- `dpea-pi-imager.desktop` - Linux (mark executable / "Allow launching").
+
+Requires Raspberry Pi Imager installed and internet access. No GitHub account
+needed (public repo). These are meant to be handed to students, e.g. from the
+student setup repo.

imager-launchers/dpea-pi-imager.bat

@@ -0,0 +1,4 @@
+@echo off
+rem Windows: double-click to launch Raspberry Pi Imager preloaded with the DPEA
+rem image list, so "DPEA Pi" appears with the Customisation panel enabled.
+start "" "%ProgramFiles%\Raspberry Pi Imager\rpi-imager.exe" --repo https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json

imager-launchers/dpea-pi-imager.command

@@ -0,0 +1,5 @@
+#!/bin/bash
+# macOS: double-click to launch Raspberry Pi Imager preloaded with the DPEA image
+# list, so "DPEA Pi" appears in the OS list with the Customisation panel enabled.
+exec "/Applications/Raspberry Pi Imager.app/Contents/MacOS/rpi-imager" \
+  --repo https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json

imager-launchers/dpea-pi-imager.desktop

@@ -0,0 +1,8 @@
+[Desktop Entry]
+Type=Application
+Name=DPEA Pi Imager
+Comment=Raspberry Pi Imager preloaded with the DPEA image list
+Exec=rpi-imager --repo https://github.com/dpengineering/DPEA-RaspberryPiImage/releases/latest/download/os-list.json
+Icon=rpi-imager
+Terminal=false
+Categories=Utility;