Use digest if image ref has tag and digest

The `sanity-inspect-image` Task is using `skopeo` that currently doesn't
support image references containing both tag and digest
(see containers/image#1736). The task has been
modified to check if the image reference contains both and in that case
the tag is removed and digest is used solely to reference the image.

task/sanity-inspect-image/0.1/sanity-inspect-image.yaml

@@ -36,11 +36,18 @@ spec:
       BASE_IMAGE_INSPECT=base_image_inspect.json
       RAW_IMAGE_INSPECT=raw_image_inspect.json
 
-      echo "Inspecting manifest for source image $(params.IMAGE_URL)"
-      skopeo inspect --no-tags docker://$(params.IMAGE_URL) > $IMAGE_INSPECT
-      skopeo inspect --no-tags --raw docker://$(params.IMAGE_URL) > $RAW_IMAGE_INSPECT
+      IMAGE_URL="$(params.IMAGE_URL)"
+      # Given a tag and a the digest in the IMAGE_URL we opt to use the digest alone
+      # this is because containers/image currently doesn't support image references
+      # that contain both. See https://github.com/containers/image/issues/1736
+      if [[ "${IMAGE_URL}" == *":"*"@"* ]]; then
+        IMAGE_URL="${IMAGE_URL/:*@/@}"
+      fi
+      echo "Inspecting manifest for source image ${IMAGE_URL}"
+      skopeo inspect --no-tags docker://"${IMAGE_URL}" > $IMAGE_INSPECT
+      skopeo inspect --no-tags --raw docker://"${IMAGE_URL}" > $RAW_IMAGE_INSPECT
 
-      echo "Getting base image manifest for source image $(params.IMAGE_URL)"
+      echo "Getting base image manifest for source image ${IMAGE_URL}"
       BASE_IMAGE_NAME="$(jq -r ".annotations.\"org.opencontainers.image.base.name\"" $RAW_IMAGE_INSPECT)"
       BASE_IMAGE_DIGEST="$(jq -r ".annotations.\"org.opencontainers.image.base.digest\"" $RAW_IMAGE_INSPECT)"
       if [ $BASE_IMAGE_NAME == 'null' ]; then
@@ -49,12 +56,12 @@ spec:
         BASE_IMAGE_NAME="$(jq -r ".Labels.\"org.opencontainers.image.base.name\"" $IMAGE_INSPECT)"
         BASE_IMAGE_DIGEST="$(jq -r ".annotations.\"org.opencontainers.image.base.digest\"" $IMAGE_INSPECT)"
         if [ "$BASE_IMAGE_NAME" == 'null' ]; then
-          echo "Cannot get base image info from 'Labels', please check the source image $(params.IMAGE_URL)"
+          echo "Cannot get base image info from 'Labels', please check the source image ${IMAGE_URL}"
           exit 0
         fi
       fi
       if [ -z "$BASE_IMAGE_NAME" ]; then
-        echo "Source image $(params.IMAGE_URL) is built from scratch, so there is no base image"
+        echo "Source image ${IMAGE_URL} is built from scratch, so there is no base image"
         exit 0
       fi
       BASE_IMAGE="${BASE_IMAGE_NAME%:*}@$BASE_IMAGE_DIGEST"