if [[ ! -f "${CLUSTER_TOPOLOGY_CONFIG_FILE}" ]]; then
    log 'cluster topology configuration file is not specified'
    exit 1
  fi

  export CLUSTER_NAMES
  export CLUSTER_POD_SUBNETS
  export CLUSTER_SVC_SUBNETS
  export CLUSTER_NETWORK_ID

  KUBE_CLUSTERS=$(jq '.[] | select(.kind == "Kubernetes" or .kind == null)' "${CLUSTER_TOPOLOGY_CONFIG_FILE}")

  while read -r value; do

  # ! does a variable-variable https://stackoverflow.com/a/10757531/374797
  for var in "${VARS[@]}"; do
    echo "${var}"="${!var}"
  done
else
  for var in "${VARS[@]}"; do
    # shellcheck disable=SC2163
    export "${var}"
  done

# See the License for the specific language governing permissions and
# limitations under the License.

set -e

WD=$(dirname "$0")
WD=$(cd "$WD"; pwd)

export FOR_BUILD_CONTAINER=1
# shellcheck disable=SC1090,SC1091
source "${WD}/setup_env.sh"


MOUNT_SOURCE="${MOUNT_SOURCE:-${PWD}}"
MOUNT_DEST="${MOUNT_DEST:-/work}"

if [[ "${ISTIO_ENVOY_BASE_URL}" != "https://storage.googleapis.com/istio-build/proxy" ]]; then
  AUTH_HEADER="Authorization: Bearer $(gcloud auth print-access-token)"
  export AUTH_HEADER
fi

SIDECAR="${SIDECAR:-envoy}"

# OS-neutral vars. These currently only work for linux.
ISTIO_ENVOY_VERSION="${ISTIO_ENVOY_VERSION:-${PROXY_REPO_SHA}}"

if [[ "${ISTIO_ZTUNNEL_BASE_URL}" != "https://storage.googleapis.com/istio-build/ztunnel" ]]; then
  AUTH_HEADER="Authorization: Bearer $(gcloud auth print-access-token)"
  export AUTH_HEADER
fi

ZTUNNEL_REPO_SHA="${ZTUNNEL_REPO_SHA:-$(grep ZTUNNEL_REPO_SHA istio.deps  -A 4 | grep lastStableSHA | cut -f 4 -d '"')}"
ISTIO_ZTUNNEL_VERSION="${ISTIO_ZTUNNEL_VERSION:-${ZTUNNEL_REPO_SHA}}"

cd "${ROOTDIR}"

# Get the sha of top commit
# $1 = repo
function getSha() {
  git ls-remote "https://github.com/istio/${1}.git" "refs/heads/${UPDATE_BRANCH}" | cut -f 1
}

make update-common

export GO111MODULE=on
go get -u "istio.io/api@${UPDATE_BRANCH}"
go get -u "istio.io/client-go@${UPDATE_BRANCH}"
go mod tidy

sed -i "s/^BUILDER_SHA=.*\$/BUILDER_SHA=$(getSha release-builder)/" prow/release-commit.sh

function tracing::extract_prow_trace() {
  if [[ "${PROW_JOB_ID:-}" != "" ]]; then
    local trace
    trace="$(<<< "$PROW_JOB_ID" tr -d '\-')"
    local span
    span="${trace:0:16}"
    export TRACEPARENT="01-${trace}-${span}-00"
  fi
}

function _genattrs() {
  # No upstream standard, so copy from https://github.com/jenkinsci/opentelemetry-plugin/blob/master/docs/job-traces.md
  if [[ -n "${PULL_NUMBER:=}" ]]