Suave App Hosted on IIS with HttpPlatformHandler Closes Connection

Question

I'm trying to get a basic Suave application running in IIS (IIS 10.0) using HttpPlatformHandler (version 1.2).

When I have it return a single WebPart such as

(OK "Hello World")

The application runs in IIS fine and I can make requests to it by name at http://localhost/testapp (testapp is the name of the application under the Default Web Site).

However, if I use something more complex for the WebPart such as

let app =
    choose
        [ GET >=> choose
            [ path "/hello" >=> OK "Hello GET"
              path "/goodbye" >=> OK "Good bye GET" ]
          POST >=> choose
            [ path "/hello" >=> OK "Hello POST"
              path "/goodbye" >=> OK "Good bye POST" ] ]

The website starts up but I cannot reach it by application name. I am still able to reach it by port however.

When I hit the application by name I receive an HTTP 503.2 (bad gateway) response.

The application is started from a FAKE script executed by the HttpPlatformHandler.

For context, this is the FAKE script which starts the application:

#r "./tools/FakeLib.dll"
#r "Suave.dll"

open System
open Suave
open Suave.Successful
open Fake
open System.Net
open Suave.Filters
open Suave.Sockets
open Suave.Operators
open System.IO

Environment.CurrentDirectory <- __SOURCE_DIRECTORY__

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

let serverConfig = 
    { defaultConfig with
       logger = Logging.Loggers.saneDefaultsFor Logging.LogLevel.Verbose
       bindings = [ HttpBinding.mk HTTP IPAddress.Loopback port ]
    }

let app =
  choose
    [ GET >=> choose
        [ path "/hello" >=> OK "Hello GET"
          path "/goodbye" >=> OK "Good bye GET" ]
      POST >=> choose
        [ path "/hello" >=> OK "Hello POST"
          path "/goodbye" >=> OK "Good bye POST" ] ]

startWebServer serverConfig (OK "Hello")
//startWebServer serverConfig app

The above script works as expected. However if I use the app WebPart instead of (OK "Hello") I encounter the issue described above.

For completeness here is the web.config set up for the HttpPlatformHandler:

<?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="true" startupTimeLimit="20"
              processPath=".\tools\FAKE.exe"
              arguments=".\test.fsx port=%HTTP_PLATFORM_PORT%" >
      <environmentVariables>
      </environmentVariables>
    </httpPlatform>
  </system.webServer>
</configuration>

I've reviewed the logs, but unfortunately I can't see anything that indicates an error.

I've checked the Event Viewer, and the only clue that something might be wrong is this information event in the application log:

The description for Event ID 1001 from source HttpPlatformHandler cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.

Here is a portion of the log from the case where the app does run as expected (without choose):

[V] 2016-01-19T02:43:40.6932823Z: initialising BufferManager with 827392 bytes [Suave.Socket.BufferManager]
[I] 2016-01-19T02:43:40.7114149Z: listener started in 20.885 ms with binding 127.0.0.1:18450 [Suave.Tcp.tcpIpServer]
[V] 2016-01-19T02:43:40.8146603Z: 127.0.0.1 connected, total: 1 clients [Suave.Tcp.job]
[V] 2016-01-19T02:43:40.8166665Z: reserving buffer: 811008, free count: 99 [Suave.Tcp.job] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:43:40.8217965Z: -> processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:43:40.8228181Z: reading first line of request [Suave.Web.processRequest]
[V] 2016-01-19T02:43:40.8378128Z: reserving buffer: 802816, free count: 98 [Suave.Web.readMoreData] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:43:40.8498033Z: reading headers [Suave.Web.processRequest]
[V] 2016-01-19T02:43:40.8776578Z: freeing buffer: 802816, free count: 99 [Suave.Web.split] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:43:40.8866594Z: parsing post data [Suave.Web.processRequest]
[V] 2016-01-19T02:43:40.8886553Z: <- processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:43:40.9057610Z: 'Connection: keep-alive' recurse [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:43:40.9057610Z: -> processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:43:40.9057610Z: reading first line of request [Suave.Web.processRequest]
[V] 2016-01-19T02:43:40.9057610Z: reserving buffer: 802816, free count: 98 [Suave.Web.readMoreData] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:43:45.2531307Z: reading headers [Suave.Web.processRequest]
[V] 2016-01-19T02:43:45.2541141Z: freeing buffer: 802816, free count: 99 [Suave.Web.split] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:43:45.2541141Z: parsing post data [Suave.Web.processRequest]
[V] 2016-01-19T02:43:45.2541141Z: <- processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:43:45.2551164Z: 'Connection: keep-alive' recurse [Suave.Web.httpLoop.loop]

And here is a portion of the log where the app does not work as expected (with routing via choose):

[V] 2016-01-19T02:44:59.6356127Z: initialising BufferManager with 827392 bytes [Suave.Socket.BufferManager]
[I] 2016-01-19T02:44:59.6537478Z: listener started in 20.987 ms with binding 127.0.0.1:18708 [Suave.Tcp.tcpIpServer]
[V] 2016-01-19T02:44:59.8848907Z: 127.0.0.1 connected, total: 1 clients [Suave.Tcp.job]
[V] 2016-01-19T02:44:59.8879891Z: reserving buffer: 811008, free count: 99 [Suave.Tcp.job] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:44:59.8929862Z: -> processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:44:59.8939749Z: reading first line of request [Suave.Web.processRequest]
[V] 2016-01-19T02:44:59.9068548Z: reserving buffer: 802816, free count: 98 [Suave.Web.readMoreData] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:44:59.9209857Z: reading headers [Suave.Web.processRequest]
[V] 2016-01-19T02:44:59.9259688Z: freeing buffer: 802816, free count: 99 [Suave.Web.split] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:44:59.9338521Z: parsing post data [Suave.Web.processRequest]
[V] 2016-01-19T02:44:59.9378580Z: <- processor [Suave.Web.httpLoop.loop]
[V] 2016-01-19T02:44:59.9518518Z: freeing buffer: 811008, free count: 100 [Suave.Tcp.job] [Suave.Socket.BufferManager]
[V] 2016-01-19T02:44:59.9518518Z: Shutting down transport. [Suave.Tcp.job]
[V] 2016-01-19T02:44:59.9528516Z: 127.0.0.1 disconnected, total: 0 clients [Suave.Tcp.job]

When the app executes the connection opens and then closes immediately. When I hit the app by port a new connection opens and then closes immediately (again).

Am I doing something wrong with the host configuration for the app, or am I missing something in how I'm using the choose function? Any help would be appreciated. Thank you!

Answer 1

I think the routes should look like :

path "/app/hello"