[solved] Environment variable for deployment target

I looked thorough whole docs for target variable when you do a promote operation,seems no result.

${DRONE_TARGET} not exist,How can I get target?

DRONE_TARGET is not a valid environment variable name.

You can find a list of environment variables in our documentation at this link:
https://docs.drone.io/pipeline/environment/reference/

The deployment target is passed to the environment using this environment variable:
https://docs.drone.io/pipeline/environment/reference/drone-deploy-to/