Environment Variables
WebdriverIO sets the following environment variables within every worker:
NODE_ENV
Set to 'test' if it's not already set to something else.
WDIO_LOG_LEVEL
Can be set to values trace, debug, info, warn, error, silent to write logs with corresponding details. Has priority over the passed logLevel value.
WDIO_WORKER_ID
An unique id that helps identify the worker process. It has format of {number}-{number} where the first number identifies the capability and the second the spec file that capability is running, e.g. 0-5 indicates a worker the first running the 6th spec file for the first capability.