Tutorial by Examples: d

To promote a node or set of nodes, run docker node promote from a manager node: docker node promote node-3 node-2 Node node-3 promoted to a manager in the swarm. Node node-2 promoted to a manager in the swarm. To demote a node or set of nodes, run docker node demote from a manager node: doc...

Step 1: First of all follow these two steps to add in app functionality : 1. Add the library using : repositories { mavenCentral() } dependencies { compile 'com.anjlab.android.iab.v3:library:1.0.+' } 2. Add permission in manifest file. <u...

This example will create an EC2 instance of t2.micro type in N.Virginia region running Amazon Linux. During the execution, it will ask to select the KeyPair to use and an I.P. CIDR from where you can SSH to the instance, use default to make SSH open to the internet { "AWSTemplateFormatVersion"...

You can create unlogged tables so that you can make the tables considerably faster. Unlogged table skips writing write-ahead log which means it's not crash-safe and unable to replicate. CREATE UNLOGGED TABLE person ( person_id BIGINT NOT NULL PRIMARY KEY, last_name VARCHAR(255) NOT NULL, ...

The HTTP response status code 301 Moved Permanently is used for permanent URL redirection, meaning current links or records using the URL that the response is received for should be updated. The new URL should be provided in the Location field included with the response. The 301 redirect is consider...

To query a field which name is contained in a variable, use the field function. some_field = :id some_value = 10 from p in Post, where: field(p, ^some_field) == ^some_value

For interacting with plots Matplotlib offers GUI neutral widgets. Widgets require a matplotlib.axes.Axes object. Here's a slider widget demo that ùpdates the amplitude of a sine curve. The update function is triggered by the slider's on_changed() event. import numpy as np import matplotlib.pyplot...

If you are new to middleware in Express check out the Overview in the Remarks section. First, we are going to setup a simple Hello World app that will be referenced and added to during the examples. var express = require('express'); var app = express(); app.get('/', function(req, res) { r...

Let's create middleware that adds a property called requestTime to the request object. var requestTime = function (req, res, next) { req.requestTime = Date.now(); next(); }; Now let's modify the logging function from the previous example to utilize the requestTime middleware. myLogge...

A good VOD (Video On Demand) service should start with the basics. Lets say you have a directory on your server that is not publicly accessible, yet through some sort of portal or paywall you want to allow users to access your media. var movie = path.resolve('./public/' + req.params.filename); ...

Implement onMessageReceived that will catch the notification sent from GCM server. @Override public void onMessageReceived(String from, Bundle data) { String message = data.getString("message"); Log.d(TAG, "From: " + from); Log.d(TAG, "Message: "...

To receive the notification, implement application:didReceiveRemoteNotification:fetchCompletionHandler: (or application:didReceiveRemoteNotification: for iOS < 8.0), and call GCMService:appDidReceiveMessage:message to acknowledge the reception of the message to GCM. - (void)application:(UIApplic...

This writeup walks though steps to configure Tomcat to request CAC certificates from the client. It is focused on setting up a development environment, so some features that should be considered for production are not here. (For example it shows using a self-signed certificate for https and it does...

We initialize the data: [X,Y] = meshgrid(1:2:10); Z = X.*cos(Y) - Y.*sin(X); The surface looks like the following. Now we set the points where we want to interpolate: [Vx,Vy] = meshgrid(1:0.25:10); We now can perform nearest interpolation, Vz = interp2(X,Y,Z,Vx,Vy,'nearest'); line...

We will use the following data: x = 1:5:50; y = randi([-10 10],1,10); Hereby x and y are the coordinates of the data points and z are the points we need information about. z = 0:0.25:50; One way to find the y-values of z is piecewise linear interpolation. z_y = interp1(x,y,z,'linear'); ...

Use conditional compilation to ensure that code only compiles for the intended instruction set (such as x86). Otherwise code could become invalid if the program is compiled for another architecture, such as ARM processors. #![feature(asm)] // Any valid x86 code is valid for x86_64 as well. Be ca...

#![feature(asm)] #[cfg(any(target_arch="x86", target_arch="x86_64"))] fn subtract(first: i32, second: i32) { unsafe { // Output values must either be unassigned (let result;) or mutable. let result: i32; // Each value that you pass in will b...

One implementation of the io.Reader interface can be found in the bytes package. It allows a byte slice to be used as the source for a Reader. In this example the byte slice is taken from a string, but is more likely to have been read from a file or network connection. message := []byte("Hello...

Sometimes it may be required to find out which directory consuming how much disk space especially when you are used df -h and realized your available disk space is low. du: du command summarizes disk usage of the set of FILEs, recursively for directories. It's often uses with -sh option: -s, --s...

First, ensure you have installed mongodb and express via npm. Then, in a file conventionally titled db.js, use the following code: var MongoClient = require('mongodb').MongoClient var state = { db: null, } exports.connect = function(url, done) { if (state.db) return done() M...