learncodeacademy

###Doing Express.js Async With Generators###

Using Co library, run generators as responses by wrapping Co and adding an extra function to handle errors

• Because Co always runs the last argument as a callback...so it would always runs next() by default
• This function only runs next if there's an error

//assign this to the Co module somewhere in application bootstrapping, 
//so you can do var ce = require('co').coExpress in each router file
co.coExpress = (generator) => {
  return (...args) => {

learncodeacademy

#include "ergodox_ez.h"
#include "debug.h"
#include "action_layer.h"

#define BASE  0 // default layer
#define MDIA  1 // mouse/media keys
#define ARROW 2 // arrow keys

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
/* Keymap 0: Basic layer

learncodeacademy

FROM node:0.12.0

# use changes to package.json to force Docker not to use the cache
# when we change our application's nodejs dependencies:
ADD package.json /tmp/package.json
RUN cd /tmp && mkdir data && npm install --production --unsafe-perm
RUN mkdir -p /app && cp -a /tmp/node_modules /app/ && cp -a /tmp/data /app/

# From here we load our application's code in, therefore the previous docker
# "layer" thats been cached will be used if possible

learncodeacademy

##The Good, The Bad, & The Ugly Ways of handling Async Operations With Javascript## #####Callbacks < Promises < Generators#####

---

###An Example: 5 in-sequence Async Operations### (also see parallel-sequence example: https://gist.github.com/willrstern/af3a3308fc5864cf48f8)

---

###The Ugly Way: Callbacks### After each function takes place, handle any errors & do the next thing - It's easy to walk through the code and understand what's going on...but it's ugly as sin

learncodeacademy

pipeline:
  slack:
    image: plugins/slack
    webhook: <your slack webhook url>
    channel: deployments
    username: drone
    template: "<{{build.link}}|Deployment #{{build.number}} started> on <http://github.com/{{repo.owner}}/{{repo.name}}/tree/{{build.branch}}|{{repo.name}}:{{build.branch}}> by {{build.author}}"
    when:
      branch: [ master, staging ]
  build:

learncodeacademy

Running a High Availability Service on CoreOS using Docker, Fleet, Flannel, Etcd, Confd & Nginx

• View the diagram of what's going on: https://drive.google.com/file/d/0B74l6vUHf9HrMzNrYUlyMm40RWs/view?usp=sharing

Tools used:

• coreos: server machine clustering via a shared cloud-config.yml
• etcd: key value store for service registration and discovery
• fleet: scheduling/failover of docker containers across coreos cluster
• flannel: Gives each docker container a unique ip that allows you to access the internal port (i.e. port 80 not 32679)
• confd: watch etcd for nodes arriving/leaving - template nginx configuration files / reload nginx on change

learncodeacademy

Start Training!...Here's the data, we'll do 2 iterations:
[ { input: [ 0, 1 ], output: [ 1, 0 ] },
  { input: [ 1, 1 ], output: [ 1, 1 ] } ]
======== TRAINING ITERATION 1 =========
--------- Run input set 0: 0,1 ----------
-> Layer 2 has 3 nodes
   START NODE: 0
   -> bias for node 0: 0.13861538469791412
   -> weights for node 0:
     -> input value: 0, weight: -0.03485306352376938

learncodeacademy

##Example Task: Make 2 parallel (simultaneous) async calls, then one async call when they've resolved##

##The Good Way: Promises##

//with bluebird library
var parallelCalls = [
  getUrl('/api/profile'),
  getUrl('/api/accounts')
];
//spread is like .then(), except it apply()s the array of responses as individual arguments

learncodeacademy

Deploying a node app with Forever is great...until your server restarts unexpectedly. Then your app stops running and you have to re-deploy.

To get around this, we're going to run our node app as an Upstart service. Upstart services are great, because, once started, the system auto-restarts them if they fail, or if the server restarts.

###Step 1: Create a service for your node app

• ssh in as root ssh root@youripaddress
• Create a node-app.conf file in /etc/init
  IMPORTANT: whatever filename you pick is what you will use to start|stop|restart your service i.e. service node-app start

learncodeacademy

##Setup your server (this would ideally be done with automated provisioning)

• add a deploy user with password-less ssh see this gist
• install forever npm install -g forever

##Install flightplan

• npm install -g flightplan
• in your project folder npm install flightplan --save-dev
• create a flightplan.js file