via gsutil
Install the gcloud CLI
Download and install the gcloud CLI from Google.
https://cloud.google.com/sdk/docs/install
gcloud auth or activate service account
Documentation to google cloud CLI auth.
https://cloud.google.com/sdk/gcloud/reference/auth/login
Activate service account by .json file.
gcloud auth activate-service-account --key-file {KEY_FILE}
Obtain an ID token.
To obtain an ID token use either of those two commands, depending on if you need to impersonate a service account or not.
Using service account
gcloud auth activate-service-account --key-file {KEY_FILE}
{KEY_FILE}: Path to your .json key file for gcloud CLI.
Using current account
gcloud auth print-identity-token
Using impersonating of service account
gcloud auth print-identity-token --impersonate-service-account {service account} --include-email
Upload to your dropzone bucket.
Documentation
You will find the upload documentation on cloud.google.com
https://cloud.google.com/storage/docs/gsutil/commands/cp
Upload
gsutil -m cp -n -r {path} gs://ucs-{appEnvId}/upload
{path}: Local path to your packaged unreal application
{appEnvId}: Your environment id which is printed on General Info page