Jimmy Byrd TheAngryByrd

Railway Oriented Programming and F# Result

Full source: https://gist.github.com/mrange/aa9e0898492b6d384dd839bc4a2f96a1

Option<_> is great for ROP (Railway Oriented Programming) but we get no info on what went wrong (the failure value is None which carries no info).

With the introduction F# 4.1 we got Result<_, _> a "smarter" Option<_> as it allows us to pass a failure value.

However, when one inspects the signature of Result.bind one sees a potential issue for ROP:

El Capitan OSX Vagrant port forwarding rules to use privileged ports 80 and 443

Due to the OSX limitations in ports below 1024, in order to use them without running as root the virtualbox headless you can do the following workaround, (remember the command ipfw is deprecated on El Capitan)

In the Vagrant file use ports over 1024, for instance change 80 and 443 to 8080 and 8043.

  # Apache
  config.vm.network "forwarded_port", guest: 80, host: 8080

General

Does the code perform its intended function?
Is all the code easily understood?
Is there any redundant or duplicate code?
Is the code as modular as possible?
Can any global variables be replaced?
Is there any commented out code?
Can any of the code be replaced with library functions?
Can any logging or debugging code be removed?

Manage SSL Certificates for Mono with Certificate Manager

For more details, see certmgr.

Note for commands to work, certificate must be in DER format.

Valid certificate store names are:

Trust (ROOT CA)
CA (Intermediate CA)

Postgres Cheatsheet

This is a collection of the most common commands I run while administering Postgres databases. The variables shown between the open and closed tags, "<" and ">", should be replaced with a name you choose. Postgres has multiple shortcut functions, starting with a forward slash, "". Any SQL command that is not a shortcut, must end with a semicolon, ";". You can use the keyboard UP and DOWN keys to scroll the history of previous commands you've run.

Setup

installation, Ubuntu

http://www.postgresql.org/download/linux/ubuntu/ https://help.ubuntu.com/community/PostgreSQL

	#!/usr/bin/env bash
	DOTNET_CLI_PATH="$(dirname $(which dotnet))/sdk/$(dotnet --version)"
	export MSBuildExtensionsPath="$DOTNET_CLI_PATH/"
	export CscToolExe="$DOTNET_CLI_PATH/Roslyn/RunCsc.sh"
	export MSBuildSDKsPath="$DOTNET_CLI_PATH/Sdks"
	msbuild /nologo /v:minimal "$@"

	using System;
	using System.Threading;

	/// <summary>
	/// A base class for disposables that need exactly-once semantics in a threadsafe way. All disposals of this instance block until the disposal is complete.
	/// </summary>
	/// <remarks>
	/// <para>If <see cref="Dispose()"/> is called multiple times, only the first call will execute the disposal code. Other calls to <see cref="Dispose()"/> will wait for the disposal to complete.</para>
	/// </remarks>
	public sealed class AnonymousDisposable : IDisposable

	sysctl -w fs.file-max=12000500
	sysctl -w fs.nr_open=20000500
	ulimit -n 4000000
	sysctl -w net.ipv4.tcp_mem='10000000 10000000 10000000'
	sysctl -w net.ipv4.tcp_rmem='1024 4096 16384'
	sysctl -w net.ipv4.tcp_wmem='1024 4096 16384'
	sysctl -w net.core.rmem_max=16384
	sysctl -w net.core.wmem_max=16384
	wget http://packages.erlang-solutions.com/erlang-solutions_1.0_all.deb
	sudo dpkg -i erlang-solutions_1.0_all.deb

	user web;

	# One worker process per CPU core.
	worker_processes 8;

	# Also set
	# /etc/security/limits.conf
	# web soft nofile 65535
	# web hard nofile 65535
	# /etc/default/nginx

	(*
	This gist runs a 3 in memory node EventStore cluster
	and a client that send messages to the cluster

	To use the web interface, copy EventStore web folders.
	You can found them in the server distribution at http://geteventstore.com/downloads/.
	Then connect to http://localhost:2113/

	You can view the cluster status at:
	http://localhost:2113/web/gossip.htm