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# make this script run, update your gist with the running script, and it's
# output in a separate gist.  the entire quzi should take 1-3 minutes, but you
# get 5.
#


# the meat - take < 5 minutes to do this
#
  assert :hash do
    x = x.to_h

benolee

I = -> x { x }
C = -> x { -> y { -> z { x[z][y] } } }
T = -> C[I]
K = -> x { -> y { x } }
U = -> f { f[f] }
# I know, this technically isn't the Y combinator,
# and it isn't exactly the Z combinator either (like Y, but for applicative order languages).
Y = -> g { U[-> f { -> x { g[U[f]][x] } } ] }

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Introduction

An introduction to curl using GitHub's API

The Basics

Makes a basic GET request to the specifed URI

curl https://api.github.com/users/caspyin

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Debugging ruby performance - Aman Gupta

C, Linux, networks, cpu, and memory usage

• lsof -nPp <pid>
• tcpdump
• write the data to a file, load it up in wireshark
• strace, trace systems calls and signals (jump into kernelspace)
• SIGVTALRM, ruby 1.8 every 10msec to switch threads (green threads)
• posix-spawn instead of fork-exec, check out posix-spawn gem
• ltrace

– ltrace -c ruby foo.rb # summary mode

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#!/bin/bash
source mysql_access
TODAY=$(date +"%Y-%m-%d_%H%M%S")

CHECK_RETAINER=$(
                 mysql api_test \
                   -u$MYSQL_USER \
                   -p$MYSQL_PASS \
                   -h$SOURCE_HOST \
                   --socket=$MYSQL_SOCK \

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From https://github.com/GhostGroup/infrastructure/pull/180

Header verification

Use socat to eavesdrop on the Nginx -> Unicorn socket-based comms.

ubuntu@ip-10-0-191-247:/etc/nginx/sites-enabled$ SOCK=/var/www/shared/.unicorn.sock [49/144]

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---

break /home/shim/Documents/foreman/dynflow/lib/dynflow/utils.rb:60

Why do we need indifferent_hash while saving?

 "/home/shim/Documents/foreman/dynflow/lib/dynflow/utils.rb:60:in `indifferent_hash'",
 "/home/shim/Documents/foreman/dynflow/lib/dynflow/persistence_adapters/sequel.rb:268:in `extract_metadata'",
 "/home/shim/Documents/foreman/dynflow/lib/dynflow/persistence_adapters/sequel.rb:226:in `prepare_record'",
 "/home/shim/Documents/foreman/dynflow/lib/dynflow/persistence_adapters/sequel.rb:236:in `save'",
 "/home/shim/Documents/foreman/dynflow/lib/dynflow/persistence_adapters/sequel.rb:125:in `save_action'",

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This is Japanese-English translation of my diary articles

• http://www.atdot.net/~ko1/diary/201502.html#d16
• http://www.atdot.net/~ko1/diary/201502.html#d17

These articles demonstration how to find out memory issues and tuning.

• How to estimate memory consumption
• How to use allocation_tracer gem to know object creation details
• How to optimize this typical issue in VM optimization

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require 'fiber'
require 'concurrent' # gem install concurrent-ruby
Thread.abort_on_exception = true

class Async
  def self.perform(&block)
    instance = new
    instance.instance_eval(&block)
    until instance.dispatched.value.zero? do
      unless instance.yields.empty?

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Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.