Scott Hanselman

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 Steffen 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 Steffen:

@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%:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <handlers>
            <remove name="httpplatformhandler" />
            <add name="httpplatformhandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" />
        </handlers>
        <httpPlatform stdoutLogEnabled="false" stdoutLogFile="fake.log" startupTimeLimit="20" processPath="%HOME%\site\wwwroot\packages\FAKE\tools\FAKE.exe"
                  arguments="%HOME%\site\wwwroot\build.fsx port=%HTTP_PLATFORM_PORT%">
            <environmentVariables>
              <environmentVariable name="WhateverYouLike" value="GoesHere"/> 
            </environmentVariables>            
        </httpPlatform>
    </system.webServer>
</configuration>

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 Steffen'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. <a href='https://github.com/shanselman/suavebootstrapper'>So easy to setup. Just click Deploy.</a>")

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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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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