fix(sync-k3s-images): skip updating on inconsistent release state (#54)

The k3s release index may be updated before container images are available to
use. This change updates the sync-k3s-images recipe to fail if any release images
cannot be found. The CI workflow is updated to allow failures. The workflow fails
if the sync recipe modifies the cached image digests.

.github/workflows/k3d.yml

@@ -22,7 +22,8 @@ jobs:
       - run: sudo apt-get update && sudo apt-get install -y skopeo
       - uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633
       - uses: ./actions/setup-tools
-      - run: just sync-k3s-images
+      # The sync may fail when a new K3s version is released. This is expected.
+      - run: just sync-k3s-images || true
       - run: git diff --exit-code
 
   k3s-matrix:

justfile

@@ -63,6 +63,12 @@ sync-k3s-images:
     DIGESTS=$(for tag in $(echo "$CHANNELS" | jq -r 'to_entries | .[].value' | sort -u) ; do
         jo key="$tag" value="$(just k3s-image='{{ k3s-image }}' _k3s-inspect "${tag}" | jq -r '.Digest')"
     done | jq -cs 'from_entries')
+    MISSING_CHANNELS=$(echo "$DIGESTS" | jq -r 'to_entries | map(select(.value == null) | .key) | .[]')
+    if [[ -n "$MISSING_CHANNELS" ]]; then
+        echo "Error: Digests could not be discovered for the following channels:" >&2
+        echo "$MISSING_CHANNELS" | while IFS= read -r channel; do echo "- $channel"; done >&2
+        exit 11
+    fi
     jo name='{{ k3s-image }}' channels="$CHANNELS" digests="$DIGESTS" \
         | jq . > k3s-images.json
     jq . k3s-images.json