chore: upload files to Google Storage when they exist (#28836) (#28847)

* fix: send to Google Storage when there are files

* fix: prevent failures if mage exits with 1

* fix: define variable properly

(cherry picked from commit 20d637e)

Co-authored-by: Manuel de la Peña <mdelapenya@gmail.com>

Jenkinsfile

@@ -831,20 +831,23 @@ def archiveTestOutput(Map args = [:]) {
       catchError(buildResult: 'SUCCESS', message: 'Failed to archive the build test results', stageResult: 'SUCCESS') {
         withMageEnv(version: "${env.GO_VERSION}"){
           dir(directory){
-            cmd(label: "Archive system tests files", script: 'mage packageSystemTests')
+            cmd(label: "Archive system tests files", script: 'mage packageSystemTests', returnStatus: true)
           }
         }
+
         def fileName = 'build/system-tests-*.tar.gz' // see dev-tools/mage/target/common/package.go#PackageSystemTests method
         def files = findFiles(glob: "${fileName}")
-        files.each { file ->
-          echo "${file.name}"
+
+        if (files?.length() > 0) {
+          googleStorageUploadExt(
+            bucket: "gs://${JOB_GCS_BUCKET}/${env.JOB_NAME}-${env.BUILD_ID}",
+            credentialsId: "${JOB_GCS_EXT_CREDENTIALS}",
+            pattern: "${fileName}",
+            sharedPublicly: true
+          )
+        } else {
+          log(level: 'WARN', text: "There are no system-tests files to upload Google Storage}")
         }
-        googleStorageUploadExt(
-          bucket: "gs://${JOB_GCS_BUCKET}/${env.JOB_NAME}-${env.BUILD_ID}",
-          credentialsId: "${JOB_GCS_EXT_CREDENTIALS}",
-          pattern: "${fileName}",
-          sharedPublicly: true
-        )
       }
     }
   }