Function app dependencies need to be downloaded to a common location for local developement

[Francisco-Gamino]

Currently, for the local scenario, we are downloading the function app to LocalApplicationData\AzureFunctions\FunctionAppName\ManagedDependencies. However, we should redesign this to behave more like a Nuget cache.

The proposed location could be:
LocalApplicationData\AzureFunctions<Feature><Language>, e.g.,
LocalApplicationData\AzureFunctions\ManagedDependencies\PowerShell

I

[joeyaiello]

Quoting @TylerLeonhardt, @SteveL-MSFT, and @daxian-dbw, this is infeasible as it is essentially equivalent to creating a GAC.

If you want to talk in more detail on it, find one of them offline.

[Francisco-Gamino]

@joeyaiello : Yes, we should talk more. This feature/enhancement was requested by @pragnagopa.

In the current implementation, we do multiple downloads (one per function app). I think we can do a better. I will reopen the issue so we can discuss it.

cc: @TylerLeonhardt @SteveL-MSFT @daxian-dbw @anirudhgarg @eamonoreilly

[AnatoliB]

If you want to go ahead and discuss this further, please involve me in this conversation. I do have some concerns (probably similar to "equivalent to creating a GAC").

[pragnagopa]

Here is my perspective:

This is an improvement work item. Size of ManagedDependencies folder for a single function app is about ~120MB. If there are more dependencies or user is trying different function app this adds up over a period of time as we do not clean up these folders. Also, when the ManagedDependencies feature expands to other languages like python, javascript etc CLI will be downloading same modules over and over.

When running in Azure, to improve startup time we need to move to a model similar to ExtensionBundles instead of downloading dependencies to user storage. I understand that would be a future work time but addressing this issue will put us in the right direction for when we do switch to a model where dependencies are completely managed by us

@Francisco-Gamino / @eamonoreilly / @anirudhgarg - Please feel free to move this to backlog if you think it is not a higher priority item. We do have to revisit the design when adding ManagedDependecies feature to other languages.