JoshuaGross

/**
 * Copyright 2017, Joshua Gross, All Rights Reserved.
 * Released under the MIT license.
 */

/**
 * Each BST is represented as its own root.
 * BSTs have no rebalancing, so tree shape can get gnarly real quick!
 */
function BST (key, value, left, right) {

JoshuaGross

Installing

Add this line to a Dockerfile to install and configure DogStatsD in the container. Requires that apt-get is available on the system.

This script will install curl in your environment but not remove it; you should uninstall it if you don't want it available in the container.

These script uses md5sum to validate all external scripts that are

JoshuaGross

Python "image not found" error resolution

This is an error that seems to occur on OS X El Capitan. You may see errors like this that did not occur before:

$ ./my_python_script.py
Traceback (most recent call last):
  File "./my_python_script.py", line 17, in <module>
    import psycopg2
 File "/Users/joshuagross/miniconda2/envs/my_env/lib/python2.7/site-packages/psycopg2/__init__.py", line 50, in 

JoshuaGross

Keybase proof

I hereby claim:

• I am joshuagross on github.
• I am joshuagross (https://keybase.io/joshuagross) on keybase.
• I have a public key whose fingerprint is DC5B 28F6 29F9 D09B BFB9 7FC3 ABF0 5BA3 4B8D 6DFD

To claim this, I am signing this object:

JoshuaGross

Recently I've experienced strange issues with networking inside of Docker containers - like being unable to ping google.com from inside a container, and all of the common suggestions around DNS resolution not helping.

It turns out that Docker will copy your computer's default DNS settings into a container. If you change your DNS settings at some point - either manually or because your machine accepts defaults from your router/provider - the settings inside your cached Docker layers may no longer match what's on your machine, and certain DNS resolutions will fail in unusual ways.

My fix: docker run -it {image} /bin/bash manually (for example, docker run -it python:2.7 bash) to find the root image that is unable to resolve the domain you're interested in, and then remove the culprit with docker rmi {hash}.

JoshuaGross

# Requires pg-datediff: https://gist.github.com/JoshuaGross/18b9bb1db8021efc88884cbd8dc8fddb

select datid, query, DateDiff('second', query_start::timestamp, NOW()::timestamp) from pg_stat_activity;

JoshuaGross

console.log('echo -e "' + buf.reduce((s, x) => s + '\\x' + x, '') + '"');

Shell:

echo -e "\x85\x0\x2\x68\x0\x32\x194\x41\x247\x13\x33\x183\x212\x148\x92\x165\x68\x193\x4\x214\x164\x10\x90\x65\x80\x193\x114\x14\x255\x164\x18\x165\x77\x65\x0\x0\x9\x0\x50\x55"

JoshuaGross

// Compiles with gcc -O0 sdiff_empty.c
// After running your sdiff function once, it will run
// a second time on canned data and compare your results with
// known outputs.

#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <stdio.h>
#include <inttypes.h>

JoshuaGross

-- none of this is terribly interesting, mostly here for reference 

class Functor (f :: * -> *) where
  fmap :: (a -> b) -> f a -> f b
  (<$) :: a -> f b -> f a

-- The same as Functor! 
-- http://stackoverflow.com/questions/34732571/why-there-is-no-cofunctor-typeclass-in-haskell/34732721
class Cofunctor (f :: * -> *) where
  fmap :: (b -> a) -> f b -> f a

JoshuaGross

echo "{ \"param\": 234 }" | node -e 'var input = ""; process.stdin.on("data", function (d) { input += d.toString(); }); process.stdin.on("close", function () { console.log(JSON.parse(input).param); });'