yanana

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

yanana

import org.scalatest.prop.GeneratorDrivenPropertyChecks
import org.scalatest.{ Matchers, WordSpec }

class SomeSpec extends WordSpec with Matchers with GeneratorDrivenPropertyChecks {
  "this test should fail without sbt exceptions" in {
    forAll { value: Int =>
      assert(value !== value)
      // value shouldNot equal(value)
    }
  }

yanana

# ==== Emojis ====
# 🎨  :art: improving format/structure of the code
# 🔧  :wrench: infra/tooling
# 🔎  :mag: when adding or improving the code for monitoring
# 🐛  :bug: when fixing bug
# 👍  :+1: improved feature
# ✨  :sparkles: when adding a partial feature
# 🎉  :tada: big feature

yanana

# Set project-wide metadata
gcloud compute project-info add-metadata --metadata foo=bar,baz=bat

# Query set metadata based on a key
curl 'http://metadata/computeMetadata/v1/project/attributes/foo' -H 'Metadata-Flavor: Google' # => bar

yanana

API	Status Codes
[Twitter][tw]	200, 304, 400, 401, 403, 404, 406, 410, 420, 422, 429, 500, 502, 503, 504
[Stripe][stripe]	200, 400, 401, 402, 404, 429, 500, 502, 503, 504
[Github][gh]	200, 400, 422, 301, 302, 304, 307, 401, 403
[Pagerduty][pd]	200, 201, 204, 400, 401, 403, 404, 408, 500
[NewRelic Plugins][nr]	200, 400, 403, 404, 405, 413, 500, 502, 503, 503
[Etsy][etsy]	200, 201, 400, 403, 404, 500, 503
[Dropbox][db]	200, 400, 401, 403, 404, 405, 429, 503, 507

yanana

package gnieh.tex

import scala.language.higherKinds

/** A generic monadic interface. By implementing this trait, one can use
 *  this data together in for-comprehensions
 *
 *  @author Lucas Satabin
 */
trait Monadic[+T, M[+T] <: Monadic[T, M]] {

yanana

#!/bin/bash

# Author: Erik Kristensen
# Email: erik@erikkristensen.com
# License: MIT
# Nagios Usage: check_nrpe!check_docker_container!_container_id_
# Usage: ./check_docker_container.sh _container_id_
#
# The script checks if a container is running.
#   OK - running

yanana

// array utils
// =================================================================================================

const combine = (...arrays) => [].concat(...arrays);

const compact = arr => arr.filter(Boolean);

const contains = (() => Array.prototype.includes
  ? (arr, value) => arr.includes(value)
  : (arr, value) => arr.some(el => el === value)

yanana

/ # apk add -vvv jemalloc-dev
The following NEW packages will be installed:
  jemalloc jemalloc-doc jemalloc-dev
After this operation, 1112 KiB of additional disk space will be used.
(1/3) Installing jemalloc (3.6.0-r1)
usr/ (dir)
usr/lib/ (dir)
usr/lib/libjemalloc.so.1
(2/3) Installing jemalloc-doc (3.6.0-r1)
usr/ (dir)

yanana

import scalaz.stream.{async,Process}
import scalaz.concurrent.Task

/**
 * Try running the process `p`, retrying in the event of failure.
 * Example: `retry(Process.awakeEvery(2 minutes))(p)` will wait
 * 2 minutes after each failure before trying again, indefinitely.
 * Using `retry(Process.awakeEvery(2 minutes).take(5))(p)` will do
 * the same, but only retry a total of five times before raising
 * the latest error.