Add short commit to image tag (#229)

Author: samdoran

.tekton/pipeline-build.yaml

@@ -62,6 +62,11 @@ spec:
       type: string
       default: ""
 
+    - name: tag-prefix
+      description: Prefix added to additional tags
+      type: string
+      default: ""
+
   results:
     - name: IMAGE_URL
       description: ""
@@ -361,6 +366,10 @@ spec:
       params:
         - name: IMAGE
           value: $(tasks.build-container.results.IMAGE_URL)
+
+        - name: ADDITIONAL_TAGS
+          value:
+            - $(params.tag-prefix)$(tasks.clone-repository.results.short-commit)
       runAfter:
         - build-container
       taskRef:
@@ -442,3 +451,4 @@ spec:
 
           - name: kind
             value: task
+

.tekton/pull_request.yaml

@@ -27,7 +27,7 @@ spec:
       value: '{{ revision }}'
 
     - name: output-image
-      value: quay.io/redhat-user-workloads/cost-mgmt-dev-tenant/koku-daily:pr-{{ pull_request_number }}
+      value: quay.io/redhat-user-workloads/cost-mgmt-dev-tenant/koku-daily:pr-{{ pull_request_number }}-latest
 
     - name: image-expires-after
       value: 5d
@@ -38,6 +38,9 @@ spec:
     - name: path-context
       value: .
 
+    - name: tag-prefix
+      value: pr-{{ pull_request_number }}-
+
   pipelineRef:
     name: pipeline-build