Running Suave.io and F# with FAKE in Azure Web Apps with Git and the Deploy Button

I was told by some lovely folks in the F# community that there is a nice web framework called Suave.io. Best name ever, eh? Suave is a clean, lightweight, and very F#y (pronounced F-Sharp-ie, I say) in its syntax.

Frameworks like this do well when they are easy to deploy, especially for Hello World. I always find that if a framework can quickly and easily give me a sense of accomplishment I'll be more likely to stick with it. I like to "fall into the pit of success."

I wanted to see if I could make Suave on Azure work easily as well. With the help of Steffan Forkman and the encouragement of the F# community (who have felt historically that support for F# in Visual Studio and Azure has been lacking) I put this little proof of concept together. I used the HttpPlatformHandler that is available in Azure Web Apps now by default, along with a basic Kudu Deployment Script from my Ruby/Middleman post.

Most of the F# community uses a NuGet alternative called Paket that is more F#-friendly. There's also a tiny Paket.Bootstrapper so I could curl things down, then run Paket like this, as part of an Azure Web App deployment. This script modified from Steffan:

@echo off
cls

mkdir .paket
REM TODO - might want to do an IF EXISTS *or* a SHA check
curl https://github.com/fsprojects/Paket/releases/download/1.2.0/paket.bootstrapper.exe -L --insecure -o .paket\paket.bootstrapper.exe

.paket\paket.bootstrapper.exe prerelease
if errorlevel 1 (
  exit /b %errorlevel%
)

.paket\paket.exe restore
if errorlevel 1 (
  exit /b %errorlevel%
)

Then we need web.config to tell Azure Web Apps (IIS8+) to start FAKE to get F# and Suave going. Note the use of %HOME%, full paths and the %HTTP_PLATFORM_PORT%:

                  arguments="%HOME%\site\wwwroot\build.fsx port=%HTTP_PLATFORM_PORT%">

I added logging but it's off by default. You can use it to debug if you have issues, as the FAKE.exe output will go into a series of log files. You can then access them with the Kudu debug console.

I like running "azure site log tail YOURSITE" with the Azure Cross Platform command line. It lets me see the deployment and output as it happens.

Here is Steffan's build.fsx:

// --------------------------------------------------------------------------------------
// FAKE build script
// --------------------------------------------------------------------------------------

#r @"packages/FAKE/tools/FakeLib.dll"

open System
open System.IO
open Fake

Environment.CurrentDirectory <- __SOURCE_DIRECTORY__

// Step 2. Use the packages

#r "packages/Suave/lib/net40/Suave.dll"

open Suave // always open suave
open Suave.Http.Successful // for OK-result
open Suave.Web // for config
open Suave.Types
open System.Net

let port = Sockets.Port.Parse <| getBuildParamOrDefault "port" "8083" 

let serverConfig = 
    { defaultConfig with
       bindings = [ HttpBinding.mk HTTP IPAddress.Loopback port ]
    }

startWebServer serverConfig (OK "Hello World! It's Suave.io on Azure Websites. So easy to setup. Just click Deploy.") 

I just added the Azure Deploy button to my Readme.md like this. This is markdown, of course, but could be HTML

[![Deploy to Azure](http://azuredeploy.net/deploybutton.png)](https://azuredeploy.net/) 

And you can try this yourself by visiting the repository here and pressing Deploy to Azure, or hit it here:

Hopefully this is a decent clear start towards easily deploying F# Web Apps to Azure via Git, and/or the Deploy Button.

Your thoughts?

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