fix: handle idle image builder templates when retrying prefetch optimization and increase retry count (#8623)

Author: cameronmeissner

.pipelines/templates/.builder-release-template.yaml

@@ -286,7 +286,7 @@ steps:
         eq(variables.PREFETCH_COMPATIBLE, 'True')
       )
     displayName: Run Prefetch Optimization and Convert to VHD blob
-    retryCountOnTaskFailure: 3
+    retryCountOnTaskFailure: 10
     env:
       SUBSCRIPTION_ID: $(SUBSCRIPTION_ID)
       LOCATION: $(PACKER_BUILD_LOCATION)

vhdbuilder/prefetch/scripts/optimize.sh

@@ -109,8 +109,13 @@ run_image_builder_template() {
         echo "image builder template ${IMAGE_BUILDER_TEMPLATE_NAME} has been created, starting run..."
         az image builder run -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}"
     else
-        echo "will attempt to wait for image builder template ${IMAGE_BUILDER_TEMPLATE_NAME} to finish its last run..."
-        az image builder wait -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}" --custom "lastRunStatus.runState!='Running'"
+        if [ "$(az image builder show -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}" | jq -r '.lastRunStatus')" = "null" ]; then
+            echo "template ${IMAGE_BUILDER_TEMPLATE_NAME} has no lastRunStatus, will attempt to run..."
+            az image builder run -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}"
+        else
+            echo "will attempt to wait for image builder template ${IMAGE_BUILDER_TEMPLATE_NAME} to finish its last run..."
+            az image builder wait -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}" --custom "lastRunStatus.runState!='Running'"
+        fi
     fi
 
     template_run_state=$(az image builder show -n "${IMAGE_BUILDER_TEMPLATE_NAME}" -g "${IMAGE_BUILDER_RG_NAME}" | jq -r '.lastRunStatus.runState')