Add information about Terraform provider plugin caching

[dataviruset]

Background On every Terragrunt plan/apply, it will download the provider plugins over and over again (not sure if this is a bug in itself), consuming several hundred megabytes on every Terragrunt run, but after enabling the plugin_cache_dir it stops doing so.

Suggested solution In the caching section of the website I think there should be a page where people are reminded to configure Terraform's provider plugin caching. Specifically to create a plugin_cache_dir and add it to ~/.terraformrc as it's very useful when working with multiple Terragrunt folders that depend on each other and have some shared dependencies like the AWS provider plugin.

[jcolfej]

I've been using this feature for several months now, and I can confirm that it has several advantages.

Above all, it improves execution speed for massive actions, such as plan/apply on several modules!

I proposed a PR to add a section in the documentation ;)

[lev-ok]

Unfortunately, this will not work properly with run-all commands, Why Terraform’s built-in provider caching doesn’t work.

[dataviruset]

Seems Terragrunt has implemented its own provider caching! 🎉 #3001 I'm gonna try it out.

It also means this issue is a duplicate of #2920.

[brikis98]

Yes indeed. Please try out Terragrunt's new provider caching feature: https://terragrunt.gruntwork.io/docs/features/provider-cache/.

There is more work to do, but that's captured in https://github.com/gruntwork-io/terragrunt/issues/2920, so closing in favor of that issue.