jpalomaki
commented
3 years ago :wave: @tsunamishaun and thanks for the question!
First, I am not familiar with Atlantis myself, can you briefly describe how it runs terraform/terragrunt at present?
As to your question, I have not tested this, but since terve uses simple hard links (e.g. ~/.terve/bin/terraform -> ~/.terve/opt/terraform/1.0.7) to select a tool version, and does not provide shims/wrappers to run that tool version, I'm pretty sure naive concurrent use would be racy (not safe), if several processes/threads used the same terve installation (below, 1 and 2 are concurrent processes/threads):
1 terve s tf 0.12.31 ~/.terve/bin/terraform now points to 0.12.31
2 terve s tf 1.0.7 ~/.terve/bin/terraform now points to 1.0.7
1 terraform plan 1 runs terraform 1.0.7 while it expected to run 0.12.31
...That said, here's a few potential ideas from the top of my head (NB: not necessarily disk nor bandwidth efficient), in no particular order:
- Run it on docker (pre-install terve and configure PATH in a docker image) and then run terraform within, or using, that image
- Run it on isolated VMs. This is a pattern that I have thought about myself in the context of GitHub actions, which actually runs (matrix) jobs in isolated VMs
- DIY shim (e.g. use terve to just install tool versions, and then run
~/.terve/opt/terraform/<version>in a wrapper, one way or the other) - Different user/
$HOME/$PATHper concurrent run (terve looks at the users$HOME, so you could have several.tervedirs.
If you used terragrunt, you could also perhaps leverage the --terragrunt-tfpath ~/.terve/opt/terraform/<version> option.
As to extending terve itself, an exec action such as terve e[xec] tf 0.12.31 plan, which would fork terraform directly, could work, but I'm not sure what implications that could have (stdin/stdout, exit codes, argument passing, signaling etc), so it would require more thinking to see if it'd actually be worth the added complexity.
Looking to use this for replacing tgenv/tfenv in atlantis but wondering if anyone has done this yet and if its safe for concurrency (multiple versions, multiple concurrent runs)? This was an issue early on with those other projects which was fixed in an eventual refactor. Thanks for making this project!