jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

willurd

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

meain

export default [
  "Reticulating splines...",
  "Generating witty dialog...",
  "Swapping time and space...",
  "Spinning violently around the y-axis...",
  "Tokenizing real life...",
  "Bending the spoon...",
  "Filtering morale...",
  "Don't think of purple hippos...",
  "We need a new fuse...",

coreyhaines

--colour
-I app

dedy-purwanto

# There was a day where I have too many color schemes in iTerm2 and I want to remove them all.
# iTerm2 doesn't have "bulk remove" and it was literally painful to delete them one-by-one.

# iTerm2 save it's preference in ~/Library/Preferences/com.googlecode.iterm2.plist in a binary format
# What you need to do is basically copy that somewhere, convert to xml and remove color schemes in the xml files.

$ cd /tmp/
$ cp ~/Library/Preferences/com.googlecode.iterm2.plist .
$ plutil -convert xml1 com.googlecode.iterm2.plist
$ vi com.googlecode.iterm2.plist

textarcana

#!/usr/bin/env bash

# Use this one-liner to produce a JSON literal from the Git log:

git log \
    --pretty=format:'{%n  "commit": "%H",%n  "author": "%aN <%aE>",%n  "date": "%ad",%n  "message": "%f"%n},' \
    $@ | \
    perl -pe 'BEGIN{print "["}; END{print "]\n"}' | \
    perl -pe 's/},]/}]/'

josevalim

# You will need fswatch installed (available in homebrew and friends)
# The command below will run tests and wait until fswatch writes something.
# The --stale flag will only run stale entries, it requires Elixir v1.3.
fswatch lib/ test/ | mix test --stale --listen-on-stdin

Aetherus

How to scale out a Phoenix application with websocket

Foreword

It's relatively easy to scale out stateless web applications. You often only need a reverse proxy. But for those stateful web applications, especially those applications that embeds websocket services in them, it's always a pain to distribute them in a cluster. The traditional way is introducing some external services like Redis to handle pubsub, however, in such way, you often need to change your code. Can Erlang/Elixir, the "concurrency oriented programming languages", best other languages in this use case? Has Phoenix framework already integrated the solution of horizontally scaling websocket? I'll do an experiment to prove (or disprove) that.

Resources

mcrumm

Deploying to Fly.io with SQLite

Deploying a Phoenix app to Fly.io is a breeze...is what everyone kept telling me. In fairness, I imagine the process would have been breezier had I just used postgres, but all the sqlite and litestream talk has been far too intriguing to ignore. "Wait", you say. "It is just a flat file. How much harder can it be?"

It is easy to make something harder than it should be. It is hard to take something complex and make it truly simple. flyctl launch does an amazing job at providing a simple interface to the utterly complex task of generating deployment resources, especially now that we are living in a containerd (erm, firecracker) world.

This gist is for anyone who, like me, thinks they know better than to read all of the documentation and therefore necessari