Environments get overridden when cortex cluster up commands run in parallel

[vishalbollu]

Version

<= 0.20.0

Steps to reproduce

1. run cortex cluster up --env cluster1
2. while the cluster is spinning up open a new terminal and then run cortex cluster up --env cluster2
3. After both clusters are created successfully, cortex env list

Expected behaviour

Depending on whichever cluster completed spinning up second, you will only find that only one of the environments was saved.

Suggested solution

Environments are cached after being read for the first time. When an environment is added or updated, the cached version modified and then written to disk. It is possible for the cached version to be out of sync with the actual environments file, especially for long running commands such as cortex cluster up. Refresh the cache before updating the environments file or get rid of the caching entirely.