Enable module cache location configuration with cli and config file

[SQLDBAWithABeard]

So this is related to #3283 and indeed is mentioned by @majastrz before the thread goes down a different path.

Goal

To be able to configure the location of the bicep cache via environment variable and/or configuration - via $ENV:BICEP_CACHE_LOCATION for example

Reasoning

The aim is to have a centralised container registry that holds versioned base modules but to be able to package a complete deployment package for use in a separate location (think air-gapped network, Azure Government Cloud, customers Azure Environment). We do not want to have to copy from one registry to another to achieve this.

As part of the build process for this package creation, bicep build would pull the modules from the registry into the cache. We would like to package them up for deployment and propose to copy the cache into the package.

When we need to deploy it would be easier to provide the cache location to the deployment instead of copying the files from the package into the cache location. This would also keep everything in one place and not risk rogue artifacts lying around complicating things.

We already have a version of this process using source controlled module files which requires the build process to use the correct version tag to create the package but using br:<acr>/file:tag would be significantly more elegant.

[majastrz]

This is already possible although might not be documented.

Can you try setting the BICEP_CACHE_DIRECTORY environment variable? By default it's set to ~/.bicep on Linux/Mac and %userprofile%\.bicep on Windows.

[SQLDBAWithABeard]

Ha - Thank you so much - this worked like a dream.

For those that want to know

$ENV:BICEP_CACHE_DIRECTORY = path to new cache

then

 bicep restore mywonderfulthing.bicep

will cache the files which can be packaged

then set the BICEP_CACHE_DIRECTORY var and deploy.

I literally deleted the modules from the ACR to see and it worked :-)
A little more written here. https://blog.robsewell.com/blog/bicep/iac/using-bicep-cache/