Arvind Singh arvind-india

For this example, I have a very simple Node.js applications that increments a counter stored on Redis. I want to run Redis and the node application independently as I want to have the ability to scale the node application depending on the load. To start off, I have 3 instances of the node server running the application. I have an Nginx server in front of node for load balancing the node instances.

Let’s now talk in terms of containers, specifically Docker containers. Simple; 1 container for each service/process!

1 Redis container
3 Node containers
1 Nginx container So, the overall picture looks something like this:

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

	// This function node combines all of the async values
	// reported by the sensor tag node into a single
	// payload. The flow will only continue when all values
	// have been received.

	var payload = context.get('payload') \|\| { data: {} };

	// Number of total attributes to report.
	// When we collect all attributes from the
	// sensor tag, the flow will continue.

	#!/usr/bin/env python
	# read CC2650 SensorTag by JP Mens
	# follow https://smidgeonpigeon.wordpress.com/2015/07/21/raspberry-pi-2-ble-ti-sensor-tag/
	# to get started, but use Sensortag2650.py

	import time
	import json
	import struct
	import Sensortag2650 as sensortag
	import paho.mqtt.publish as mqtt

	#!/bin/bash

	# remove exited containers:
	docker ps --filter status=dead --filter status=exited -aq \| xargs -r docker rm -v

	# remove unused images:
	docker images --no-trunc \| grep '<none>' \| awk '{ print $3 }' \| xargs -r docker rmi

	# remove unused volumes:
	find '/var/lib/docker/volumes/' -mindepth 1 -maxdepth 1 -type d \| grep -vFf <(

	# cleans all images
	docker images \| awk '{print $3}' \| xargs docker rmi

	# cleans all stopped containers
	docker rm $(docker ps -q -f status=exited)

	#!/usr/bin/env python

	# Run with no args for usage instructions
	#
	# Notes:
	# - will probably insert duplicate records if you load the same file twice
	# - assumes that the number of fields in the header row is the same
	# as the number of columns in the rest of the file and in the database
	# - assumes the column order is the same in the file and in the database
	#


	# following Python packages needs to be installed
	# xlrd, xlsxrd, unidecode, MySQLdb

	import xlrd
	import xlsxrd
	import MySQLdb as mdb
	import re
	import unidecode

	import csv
	import MySQLdb
	# open the connection to the MySQL server.
	# using MySQLdb
	mydb = MySQLdb.connect(host='igor.gold.ac.uk', user='co304so', passwd='*********', db='co304so_LondonCrime')
	cursor = mydb.cursor()
	csv_data = csv.reader(file('1.csv'))
	# execute and insert the csv into the database.
	for row in csv_data:
	cursor.execute('INSERT INTO AprilNov2013(Date,Westminster,HACKNEY,Tower_Hamlets)''VALUES(%s, %s, %s, %s)',row)

	# Dockerfile for Node-RED - pulls latest master code from git
	# Use the node.js v4 LTS engine
	FROM node:4-slim
	MAINTAINER ceejay

	RUN mkdir -p /root/.node-red
	WORKDIR /root/.node-red

	# download latest stable node-red
	RUN npm install -g --unsafe-perm node-red