Prepare for universal usage of an image index task

* Created a new task that has an appropriate name (build-image-index)
* Changed the build-image-manifest task to be a rebuild of the new
  build-image-index task
* Enabled the image index task to run and skip the generation of an
  index image. This lets the task be added into "single arch" pipelines
  as well as there are still situations where an image index should be
  created

Signed-off-by: arewm <[email protected]>

task/build-image-index/0.1/README.md

@@ -0,0 +1,22 @@
+# build-image-index task
+
+This takes existing Image Manifests and combines them in an Image Index.
+
+## Parameters
+|name|description|default value|required|
+|---|---|---|---|
+|IMAGE|The target image and tag where the image will be pushed to.||true|
+|TLSVERIFY|Verify the TLS on the registry endpoint (for push/pull to a non-TLS registry)|true|false|
+|COMMIT_SHA|The commit the image is built from.|""|false|
+|IMAGES|List of Image Manifests to be referenced by the Image Index||true|
+|IMAGE_EXPIRES_AFTER|Delete image tag after specified time resulting in garbage collection of the digest. Empty means to keep the image tag. Time values could be something like 1h, 2d, 3w for hours, days, and weeks, respectively.|""|false|
+|ALWAYS_BUILD_INDEX|Build an image index even if IMAGES is of length 1. Default true. If the image index generation is skipped, the task will forward values for params.IMAGES[0] to results.IMAGE_*.|true|false|
+|STORAGE_DRIVER|Storage driver to configure for buildah|vfs|false|
+
+## Results
+|name|description|
+|---|---|
+|IMAGE_DIGEST|Digest of the image just built|
+|IMAGE_URL|Image repository where the built image was pushed|
+|IMAGES|List of all referenced image manifests|
+

task/build-image-manifest/0.1/build-image-manifest.yaml → task/build-image-index/0.1/build-image-index.yaml

@@ -7,29 +7,33 @@ metadata:
   annotations:
     tekton.dev/pipelines.minVersion: "0.12.1"
     tekton.dev/tags: "image-build, konflux"
-  name: build-image-manifest
+  name: build-image-index
 spec:
   description: |-
-    This takes existing images and stiches them together into a multi platform image.
+    This takes existing Image Manifests and combines them in an Image Index.
   params:
-  - description: Reference of the image buildah will produce.
-    name: IMAGE
+  - name: IMAGE
+    description: The target image and tag where the image will be pushed to.
     type: string
-  - default: "true"
+  - name: TLSVERIFY
     description: Verify the TLS on the registry endpoint (for push/pull to a non-TLS registry)
-    name: TLSVERIFY
     type: string
+    default: "true"
   - name: COMMIT_SHA
-    description: The image is built from this commit.
+    description: The commit the image is built from.
     type: string
     default: ""
   - name: IMAGES
-    description: List of images that are to be merged into the multi platform image
+    description: List of Image Manifests to be referenced by the Image Index
     type: array
-  - default: ""
-    description: Delete image tag after specified time. Empty means to keep the image tag. Time values could be something like 1h, 2d, 3w for hours, days, and weeks, respectively.
-    name: IMAGE_EXPIRES_AFTER
+  - name: IMAGE_EXPIRES_AFTER
+    description: Delete image tag after specified time resulting in garbage collection of the digest. Empty means to keep the image tag. Time values could be something like 1h, 2d, 3w for hours, days, and weeks, respectively.
     type: string
+    default: ""
+  - name: ALWAYS_BUILD_INDEX
+    description: Build an image index even if IMAGES is of length 1. Default true. If the image index generation is skipped, the task will forward values for params.IMAGES[0] to results.IMAGE_*.
+    type: string
+    default: "true"
   - name: STORAGE_DRIVER
     description: Storage driver to configure for buildah
     type: string
@@ -45,14 +49,16 @@ spec:
     env:
     - name: BUILDAH_FORMAT
       value: oci
-    - name: STORAGE_DRIVER
-      value: $(params.STORAGE_DRIVER)
+    - name: COMMIT_SHA
+      value: $(params.COMMIT_SHA)
     - name: IMAGE
       value: $(params.IMAGE)
     - name: TLSVERIFY
       value: $(params.TLSVERIFY)
-    - name: COMMIT_SHA
-      value: $(params.COMMIT_SHA)
+    - name: ALWAYS_BUILD_INDEX
+      value: $(params.ALWAYS_BUILD_INDEX)
+    - name: STORAGE_DRIVER
+      value: $(params.STORAGE_DRIVER)
   steps:
   - image: quay.io/konflux-ci/buildah-task:latest@sha256:5d933087a49a6e0b959b9a9fa5a91d545380217e565d7be7cc74a9588f64c314
     # per https://kubernetes.io/docs/concepts/containers/images/#imagepullpolicy-defaulting
@@ -74,15 +80,33 @@ spec:
 
       sed -i 's/^\s*short-name-mode\s*=\s*.*/short-name-mode = "disabled"/' /etc/containers/registries.conf
 
+      if [[ $# -ne 1 && "$ALWAYS_BUILD_INDEX" != "true" ]]; then
+        echo "Skipping image index generation while supplying multiple image inputs is unsupported."
+        exit 2
+      fi
+
       image_manifests=""
       buildah manifest create "$IMAGE"
       for i in $@
       do
         TOADD="$i"
-        if [[ $(echo $i | tr -cd ":" | wc -c) == 2 ]]; then
+        TOADD_REPOSITORY="$(echo "$i" | cut -d@ -f1)"
+        TOADD_DIGEST="$(echo "$i" | cut -d@ -f2)"
+        TOADD_TAG="$(echo "$IMAGE" | cut -d: -f2)"
+        if [[ $(echo "$i" | tr -cd ":" | wc -c) == 2 ]]; then
+          #format is repository:tag@sha256:digest
           #we need to remove the tag, and just reference the digest
           #as tag + digest is not supported
-          TOADD="$(echo $i | cut -d: -f1)@sha256:$(echo $i | cut -d: -f3)"
+          TOADD_REPOSITORY="$(echo "$i" | cut -d: -f1)"
+          TOADD_DIGEST="sha256:$(echo "$i" | cut -d: -f3)"
+          TOADD="${TOADD_REPOSITORY}@${TOADD_DIGEST}"
+        fi
+        if [[ "$ALWAYS_BUILD_INDEX" != "true" ]]; then
+          echo "Skipping image index generation. Returning results for $TOADD"
+          echo -n "${TOADD_REPOSITORY}:${TOADD_TAG}" > "$(results.IMAGE_URL.path)"
+          echo -n "${TOADD_DIGEST}" > "$(results.IMAGE_DIGEST.path)"
+          echo -n "${TOADD}" > "$(results.IMAGES.path)"
+          exit 0
         fi
         echo "Adding $TOADD"
         image_manifests="${image_manifests} ${TOADD},"

task/build-image-index/0.1/kustomization.yaml

@@ -0,0 +1,5 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+- build-image-index.yaml

task/build-image-index/OWNERS

@@ -0,0 +1,5 @@
+# See the OWNERS docs: https://go.k8s.io/owners
+approvers:
+  - build-team
+reviewers:
+  - build-team

task/build-image-manifest/0.1/README.md

@@ -1,5 +1,7 @@
 # build-image-manifest task
 
+WARNING: Usage of this task is deprecated. You should use the `build-image-index` task instead.
+
 This task generates an image index from a collection of existing single platform images to create a multi-platform image.
 
 ## Parameters

task/build-image-manifest/0.1/kustomization.yaml

@@ -0,0 +1,10 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - ../../build-image-index/0.1
+
+patches:
+- path: patch.yaml
+  target:
+    kind: Task

task/build-image-manifest/0.1/patch.yaml

@@ -0,0 +1,4 @@
+---
+- op: replace
+  path: /metadata/name
+  value: build-image-manifest