if [[ -n "${PULL_NUMBER:=}" ]]
  then
    # Presubmit
    url="https://prow.istio.io/view/gs/istio-prow/pr-logs/pull/${REPO_OWNER}_${REPO_NAME}/${PULL_NUMBER}/${JOB_NAME}/${BUILD_ID},"
  else
    # Postsubmit or periodic
    url="https://prow.istio.io/view/gs/istio-prow/pr-logs/${JOB_NAME}/${BUILD_ID},"
  fi

      return 0
    fi
    outName="artifacts/${PATCH_OUT#"${ARTIFACTS}"/}"
    patchFile="${PROW_ARTIFACTS_BASE:-https://gcsweb.istio.io/gcs/istio-prow}/pr-logs/pull/${REPO_OWNER}_${REPO_NAME}/${PULL_NUMBER}/${JOB_NAME}/${BUILD_ID}/${outName}"
    echo "You can also try applying the patch file from the build artifacts:

git apply <(curl -sL \"${patchFile}\")
"
}

	jobName    = env.Register("JOB_NAME", "", "name of job").Get()
	pullNumber = env.Register("PULL_NUMBER", "", "PR of job").Get()
	repoName   = env.Register("REPO_NAME", "istio", "repo name").Get()
	repoOwner  = env.Register("REPO_OWNER", "istio", "repo owner").Get()
	buildID    = env.Register("BUILD_ID", "", "build id").Get()
	artifacts  = env.Register("ARTIFACTS", "", "artifacts base").Get()
)

func ArtifactsURL(filename string) string {