Restore script.

backup/Dockerfile

@@ -3,6 +3,7 @@ FROM docker.io/library/alpine:3.14
 RUN echo 'https://dl-cdn.alpinelinux.org/alpine/edge/testing' >> /etc/apk/repositories && \
     echo 'https://dl-cdn.alpinelinux.org/alpine/edge/community' >> /etc/apk/repositories && \
     apk add --update --no-cache \
+        findutils \
         skopeo \
         reg \
     ;

backup/backup

@@ -17,6 +17,8 @@ then
     exit 1
 fi
 
+command -v skopeo >/dev/null || { echo 'skopeo is missing.' >&2; exit 2; }
+
 registry="$1"
 dest="$2"
 
@@ -44,6 +46,7 @@ NR>2 {
     }
 }
 END {
-    exit retruncode
+    if ( exitcode == 1) print "Backup failed for some images."
+    exit exitcode
 }
 '

backup/restore

 #!/bin/sh
+set -eu
+
+usage() {
+    echo "$0: BACKUP_SOURCE REGISTRY_DOMAIN"
+}
+
+if [ "${1:-}" = -h ] || [ "${1:-}" = --help ]
+then
+    usage
+    exit 0
+fi
+
+if [ "$#" -ne 2 ]
+then
+    usage
+    exit 1
+fi
+
+command -v skopeo >/dev/null || { echo 'skopeo is missing.' >&2; exit 2; }
+
+src="$1"
+registry="$2"
+
+# There's an assumption here that filenames don't have spaces (or other such
+# characters) as the image format prohibits that and I don't want to deal with
+# such issues right now.
+
+images="$(find "$src" -maxdepth 1 -mindepth 1 -type d -printf '%f\n')"
+if [ -z "$images" ]
+then
+    echo 'No images found,' >&2
+    exit 3
+fi
+
+returncode=0
+for image in $images
+do
+    tags="$(find "$src/$image" -maxdepth 1 -mindepth 1 -type f -name '*.tar' -printf '%f\n' | sed 's/\.tar$//g')"
+    if [ -z "$tags" ]
+    then
+        echo "No tags found for image $image, skipping." >&2
+        continue
+    fi
+    for tag in $tags
+    do
+        echo "Restoring $image:$tag" >&2
+        if skopeo copy "docker-archive://$src/$image/$tag.tar" "docker://$registry/$image:$tag"
+        then
+            echo "Restore finished successfully." >&2
+        else
+            echo "Restore failed, continuing with other image." >&2
+            returncode=1
+        fi
+    done
+done
+
+if [ "$returncode" -gt 0 ]
+then
+    echo 'Restoration failed for some images.'
+fi
+exit "$returncode"