F# project support

[mikhailshilkov]

Are there plans to support F# project / function creation?
I'm willing to help with this, if you give me some high-level guidance.

[whitetigle]

+1

[ejizba]

We already have limited support for F#. In your user settings for VS Code, set "azureFunctions.projectLanguage" to "F#Script". The next time you create a project, you will not be prompted for a language and it will use F#Script instead.

With that project, you can create a new function:

(NOTE: I'm using runtime v1.x on Windows. The functions runtime doesn't support F# for v2.x yet.)

And then if you do "Run Task" from the command palette, you can run the Functions host in VS Code's task system:

The biggest piece missing is debugging, aka the "launch.json" file in the ".vscode" folder. I'm guessing it might be similar to the "launch.json" for C#, but I have no idea. Have you debugged other F# projects in VS Code that aren't related to Functions? How does that usually work? What VS Code extensions do you need?

[mikhailshilkov]

Why doesn't it appear in the default language selection?

This makes it hard to discover, while the whole point is to help people get started.

And of course, we need support for precompiled F# and v2, since that's the future, and F# tooling actually works best with those.

Debugging F# works just fine. I am able to debug precompiled v2 F# Azure Functions created manually with dotnet new command. launch.json is probably exactly the same as C# one, since it's dotnet doing all the work. Ionide is the plugin to do all things F# in VS Code.

[ejizba]

The simplest answer is because we don't think the experience I described above is good enough to display in the default language selection yet. We have the settings for more advanced users that want to explore, but we don't want people getting started on a bad/underdeveloped experience.

We're adding languages to that list on a case-by-case basis once they have full support (including debugging). I can't make any guarantees on timing for F#, but feedback like this definitely helps us prioritize which language to work on next (There's actually several languages not displayed including Bash, PowerShell, PHP, Python, TypeScript, etc.).

Based on your input and my experience with our C# support - I'm guessing we'll never add 'F#Script' to that list and instead only add 'F#' (Aka precompiled instead of script). We're using these templates for C#, but I don't think those exist for F# yet. When you used dotnet new, I assume you're not using a Function-specific template?

[mikhailshilkov]

OK, clear. F# Script might still be useful for some folks, but I don't use it.

The other languages you mention are experimental, I hope F# stands above this list.

There is Azure/azure-functions-templates#627 where we try to add F# precompiled templates and Azure/azure-functions-templates#665 to add them to your nuget package.

[forki]

Definitely interested in better tooling support for f#. We have around 40 F# functions right now and we are planning to do WAY more

[TonyHenrique]

Yes, please give F# more attention.

[Angr1st]

What is still to do here?

[ejizba]

Only piece missing is creating a function and for that we need Azure/azure-functions-templates#627 to be fixed first.

Right now you can do the following:

1. Create new project
   1. Set azureFunctions.projectLanguage in your VS Code User settings to F#. That language will be used the next time you create a project in VS Code. (Once the above is fixed, we will show "F#" in the normal "Create new project" dropdown for language)
   2. NOTE: You must be on at least v0.16.0 of our extension for this to work
2. Create new function
   1. As mentioned, this is not supported yet. In the meantime, I have an example commit here to manually create a function based on this blogpost by @mikhailshilkov.
3. Debug
4. Deploy

[Angr1st]

1. Just tested it looks good. 👍
   2., 3. and 4. I have already done. Hopefully the missing necessary PR gets merged soon.