davidglassborow

How to get on Rinkeby Testnet in less than 10 minutes

Following instructions from the excellent https://www.rinkeby.io/

Synchronizing a Full Node

A full node lets you access all state. There is a light node (state-on-demand) and wallet-only (no state) instructions as well,

davidglassborow

Deploying an F# ASP.NET Core app to Azure

Last week I spent a lot of time trying to deploy an F# ASP.NET Core app (a Giraffe app, specifically) to Azure because the information to complete all the steps was scattered in several places. So I'm writing this hopefully it will save the pain to others :)

Preparation

The following steps are mostly taken from this guide and it's only necessary to do them once:

1. Create an account in Azure (or use an existing one)
2. Create a resource group (or use an existing one)

davidglassborow

Homebrew Permissions Denied Issues Solution

Installing and fixing node.JS

---

brew install node

davidglassborow

(*
An incomplete implementation of a type-safe SQL query in F#.

The idea is that a query is built up clause by clause, by representing
each additional clause being added on to the query as a state transition
between different types of queries. We capture these different types as
phantom types to make sure that only valid transitions (query clause
additions) as defined by us can be carried out.

The final result is a 'total query' that can be converted to a string,

davidglassborow

let ParallelThrottledIgnore (startOnCallingThread:bool) (parallelism:int) (xs:seq<Async<_>>) = async {
  let! ct = Async.CancellationToken
  let sm = new SemaphoreSlim(parallelism)
  let count = ref 1
  let res = TaskCompletionSource<_>()
  let tryWait () =
    try sm.Wait () ; true
    with _ -> false
  let tryComplete () =
    if Interlocked.Decrement count = 0 then

davidglassborow

// From https://github.com/jet/kafunk/blob/master/src/kafunk/Utility/BoundedMb.fs

[<AutoOpen>]
module internal Kafunk.BoundedMb

// TODO: https://github.com/fsprojects/FSharpx.Async

open System
open System.Collections.Generic

davidglassborow

let timeoutNone (timeoutMs:int) (a:Async<'a>) : Async<'a option> = async {
  let! ct = Async.CancellationToken
  let res = TaskCompletionSource<_>()
  use cts = CancellationTokenSource.CreateLinkedTokenSource ct
  res.Task.ContinueWith (fun _ -> cts.Cancel ()) |> ignore
  use timer = new Timer((fun _ -> res.TrySetResult None |> ignore), null, timeoutMs, Timeout.Infinite)
  Async.StartThreadPoolWithContinuations (
    a,
    (fun a -> res.TrySetResult (Some a) |> ignore),
    (fun e -> res.TrySetException e |> ignore),

davidglassborow

Tutorial: Designing a GraphQL API

This tutorial was created by Shopify for internal purposes. We've created a public version of it since we think it's useful to anyone creating a GraphQL API.

It's based on lessons learned from creating and evolving production schemas at Shopify over almost 3 years. The tutorial has evolved and will continue to change in the future so nothing is set in stone.

davidglassborow

// Phantom types - http://web.archive.org/web/20100615031841/http://blog.matthewdoig.com/?p=138
 
// Rather than DUs, just use simple marker interfaces
type Zero = interface end
type Succ<'length> = interface end

type Phantom<'a,'length> = Phantom of 'a list
let toList (Phantom l) = l

let nil = Phantom [] : Phantom<_,Zero>

davidglassborow

$userPath = $env:USERPROFILE
$pathExclusions = New-Object System.Collections.ArrayList
$processExclusions = New-Object System.Collections.ArrayList

$pathExclusions.Add('C:\Windows\Microsoft.NET') > $null
$pathExclusions.Add('C:\Windows\assembly') > $null
$pathExclusions.Add($userPath + '\AppData\Local\Microsoft\VisualStudio') > $null
$pathExclusions.Add('C:\ProgramData\Microsoft\VisualStudio\Packages') > $null
$pathExclusions.Add('C:\Program Files (x86)\MSBuild') > $null
$pathExclusions.Add('C:\Program Files (x86)\Microsoft Visual Studio 14.0') > $null