Trevor Hartman devth

A Quick and Dirty Lens primer

Why does Lens exist? Well, Haskell records suck, for a number of reasons. I will enumerate them using this sample record.

data User = User { login    :: Text
                 , password :: ByteString
                 , email    :: Text
                 , created  :: UTCTime
 }

What it is

Problem: Terraform doesn't play nicely with pre-existing infrastructure.

Solution: Officially there isn't one - but here's a work-around that does the trick.

Summary

Declare a new, temporary resource in your Terraform plan that is nearly identical to the extant resource.
Apply the plan, thus instantiating the temporary "twinned" resource and building a state file.

	val des = scala.concurrent.ExecutionContext.global

	import scala.concurrent._
	import duration._

	def ct = Thread.currentThread.getName

	val n = Runtime.getRuntime.availableProcessors

	def hogThread(sec:Int) = future {

	(def ^ThreadLocal stack-depth (ThreadLocal.))

	(def ^Executor overflow-protection-pool
	(let [cnt (atom 0)]
	(Executors/newCachedThreadPool
	(thread-factory #(str "manifold-overflow-protection-pool-" (swap! cnt inc))))))

	(def ^:const max-depth 50)

	(defmacro without-overflow [& body]

	# The blog post that started it all: https://neocities.org/blog/the-fcc-is-now-rate-limited
	#
	# Current known FCC address ranges:
	# https://news.ycombinator.com/item?id=7716915
	#
	# Confirm/locate FCC IP ranges with this: http://whois.arin.net/rest/net/NET-165-135-0-0-1/pft
	#
	# In your nginx.conf:

	location / {

	FIELDS = ['cmd', 'command', 'start', 'end', 'delta', 'msg', 'stdout', 'stderr']

	def human_log(res):

	if type(res) == type(dict()):
	for field in FIELDS:
	if field in res.keys():
	encoded_field = res[field].encode('utf-8')
	print '\n{0}:\n{1}'.format(field, encoded_field)

	" run command
	" no stdin
	" output displayed in "Press enter to continue" style
	" current buffer untouched
	:!uptime

	" run command
	" pipe range of text to command on stdin
	" output replaces the range in the current buffer
	:RANGE!grep foo

	-- Optimized MYSQL schema for datomic
	-- Unfortunately the bin/sql/mysql-*.sql bootstrapping files for datomic are not
	-- very good, and can actually cause failures if not adjusted.
	-- One symptom of this is the following error:

	-- SQL Error (1071): Specified key was too long; max key length is 767 bytes.

	-- Reported here: https://support.cognitect.com/entries/28462168-MySQL-Caveats

	-- This is caused by the default collation for the `id` column possibly being

	import java.util.concurrent._

	/**
	* A thread pool for superstitious parent threads who
	* know they shouldn't let their child threads back in the pool after
	* eating, without waiting at least `crampFactor` milliseconds.
	*/
	object Superstitious {
	def pool(crampFactor: Long) = new ThreadPoolExecutor(
	0, Int.MaxValue, 60L, TimeUnit.SECONDS, new SynchronousQueue[Runnable]) {

	#!/bin/sh

	PROJECT=thockin-dev
	ZONE=us-central1-b
	K8S_MIG=kubernetes-minion-group

	# Assume I have 2 kubernetes services running, svc1 and svc1. Both are type
	# NodePort with ports defined below. I want to expose them as hostnames
	# defined below.
	SVC1_NODE_PORT=30001