would it be possible to expose the ip address of the underlying host node to the docker containers in an environment variable?

i am running builds inside the container and those builds have integration tests that need to talk to a mysql container. i am able to spin up the container fine by mounting in /var/run/docker.sock but i'm unable to communicate w/ it b/c i don't know it's ip address and linking the containers is not an option.

i do have some work arounds available, but this would be a huge help if it's possible.