jkrasnay

Re-frame Subscription Helpers

There are a couple of common problems with Re-frame subscriptions that I’d like to solve:

1. Because subscriptions are registered via keywords, the ClojureScript compiler does nothing to help check that we haven’t made a typo when subscribing.

2. We often need to use the same logic to access a value in the app DB in both a subscription and in events.

I’ve come up with the following structure. First we create the accessor function, which can be used by both the subscription and any events. (This of course implies that the namespace where we implement our events must refer to the namespace where we define our subscriptions.)

athomasoriginal

(ns ^:figwheel-hooks reitit-routing
  (:require
    [reagent.core         :as r]
    [reagent.dom          :as r.dom]
    [reitit.frontend      :as rf]
    [reitit.frontend.easy :as rfe]
    [reitit.coercion.spec :as rss]
    [fipp.edn             :as fedn]))

;; State

saurabhnanda

Tuning ZFS + Postgres to outperform EXT4 + Postgres

Please refer to ZFS 2-3x slower than EXT4 to see how ZFS defaults + Postgres defaults severely underperform EXT4 defaults + Postgres defaults (and also to know more about the system on which these benchmarks were performed). This page documents how to tune ZFS + Postgres to give better performance for the tpcb-like benchmark.

BIG FAT WARNING

Please do not copy these settings blindly because I am myself not clear on why/how these settings had the impact they did. For example, I cannot explain why full_page_writes=off independently did not give that much boost, nor did an optimized PG configuration. However, putting both of them together gave a 2-4x boost compared to baseline numbers.

Benchmark results

PhilipSchmid

Interface bonding

Configure a LACP active network interface bonding on Ubuntu 18.04 using netplan:

root@srv01:~# mv /etc/netplan/50-cloud-init.yaml /etc/netplan/01-netcfg.yaml
root@srv01:~# cat /etc/netplan/01-netcfg.yaml 
network:
    version: 2
    renderer: networkd
 ethernets:

mort3za

# Generate a new pgp key: (better to use gpg2 instead of gpg in all below commands)
gpg --gen-key
# maybe you need some random work in your OS to generate a key. so run this command: `find ./* /home/username -type d | xargs grep some_random_string > /dev/null`

# check current keys:
gpg --list-secret-keys --keyid-format LONG

# See your gpg public key:
gpg --armor --export YOUR_KEY_ID
# YOUR_KEY_ID is the hash in front of `sec` in previous command. (for example sec 4096R/234FAA343232333 => key id is: 234FAA343232333)

conan

(require '[cemerick.url :as url]
         '[clojure.spec.alpha :as s]
         '[clojure.spec.gen.alpha :as gen]
         '[clojure.string :as string])

(def non-empty-string-alphanumeric
  "Generator for non-empty alphanumeric strings"
  (gen/such-that #(not= "" %)
    (gen/string-alphanumeric)))

oznu

QEMU + Ubuntu ARM aarch64

These are the steps I used to get Ubuntu ARM aarch64 running with QEMU on OSX.

Get Ubuntu Image and QEMU EFI:

wget https://cloud-images.ubuntu.com/releases/16.04/release/ubuntu-16.04-server-cloudimg-arm64-uefi1.img
wget https://releases.linaro.org/components/kernel/uefi-linaro/latest/release/qemu64/QEMU_EFI.fd

pesterhazy

;; React supports "refs" as a way for a component to get a 
;; handle to its children. Classically, refs were string-based.
;; Recent versions of React support callback attributes as a
;; more elegant variant of accessing DOM notes or components.
;;
;; This example uses a Form-3 component as per
;; https://github.com/Day8/re-frame/wiki/Creating-Reagent-Components
;; 
;; For callback refs, see React's documentation
;; https://facebook.github.io/react/docs/more-about-refs.html

ghoseb

(ns clj-spec-playground
  (:require [clojure.string :as str]
            [clojure.spec :as s]
            [clojure.test.check.generators :as gen]))

;;; examples of clojure.spec being used like a gradual/dependently typed system.

(defn make-user
  "Create a map of inputs after splitting name."
  ([name email]

jbnunn

$LocalTempDir = $env:TEMP; $ChromeInstaller = "ChromeInstaller.exe"; (new-object    System.Net.WebClient).DownloadFile('http://dl.google.com/chrome/install/375.126/chrome_installer.exe', "$LocalTempDir\$ChromeInstaller"); & "$LocalTempDir\$ChromeInstaller" /silent /install; $Process2Monitor =  "ChromeInstaller"; Do { $ProcessesFound = Get-Process | ?{$Process2Monitor -contains $_.Name} | Select-Object -ExpandProperty Name; If ($ProcessesFound) { "Still running: $($ProcessesFound -join ', ')" | Write-Host; Start-Sleep -Seconds 2 } else { rm "$LocalTempDir\$ChromeInstaller" -ErrorAction SilentlyContinue -Verbose } } Until (!$ProcessesFound)