jobs/nodeimage: use the base image digest for FROM

Instead of relying on the tag of the base image, first grab the manifest
digest than pass that value to the builders.
This will avoid reusing stale images that may be present in the local
containers storage when building.

Co-authored-by: Renata Ravanelli <renata.ravanelli@gmail.com>

Author: 2 people

utils.groovy

@@ -921,6 +921,16 @@ def delete_tags(digests, repo, manifest_tag, authfile = "") {
     }]}
 }
 
+def get_manifest_digest(image) {
+    if (image != '' && !image.contains('@')) {
+        shwrap("skopeo inspect --raw -n docker://${image} > manifest.json")
+        def digest = shwrapCapture("skopeo manifest-digest manifest.json")
+        shwrap("rm -f manifest.json")
+        image = "${image.split(':')[0]}@${digest}"
+    }
+    return image
+}
+
 def build_and_push_image(params = [:]) {
 // Available parameters:
     // arches:               list    -- List of architectures to run against
@@ -940,6 +950,7 @@ def build_and_push_image(params = [:]) {
     def extra_build_args = params.get('extra_build_args', "");
     def v2s2 = params.get('v2s2', false);
 
+    from = get_manifest_digest(from)
     def digests = build_remote_image(params['arches'], params['src_commit'], params['src_url'], params['staging_repository'],
                                      params['image_tag_staging'], secret, from, extra_build_args)
     stage("Push Manifest") {