Tutorial by Examples: di

WORKDIR /path/to/workdir The WORKDIR instruction sets the working directory for any RUN, CMD, ENTRYPOINT, COPY and ADD instructions that follow it in the Dockerfile. If the WORKDIR doesn’t exist, it will be created even if it’s not used in any subsequent Dockerfile instruction. It can be used mu...

The CMD instruction has three forms: CMD ["executable","param1","param2"] (exec form, this is the preferred form) CMD ["param1","param2"] (as default parameters to ENTRYPOINT) CMD command param1 param2 (shell form) There can only be one CMD ins...

ONBUILD [INSTRUCTION] The ONBUILD instruction adds to the image a trigger instruction to be executed at a later time, when the image is used as the base for another build. The trigger will be executed in the context of the downstream build, as if it had been inserted immediately after the FROM in...

Make sure your image object is fully loaded before you try to draw it on the canvas with context.drawImage. Otherwise the image will silently fail to display. In JavaScript, images are not loaded immediately. Instead, images are loaded asynchronously and during the time they take to load JavaScript...

When a runtime error occurs, good code should handle it. The best error handling strategy is to write code that checks for error conditions and simply avoids executing code that results in a runtime error. One key element in reducing runtime errors, is writing small procedures that do one thing. Th...

By Assembly Name, add library Add-Type -AssemblyName "System.Math" or by file path: Add-Type -Path "D:\Libs\CustomMath.dll" To Use added type: [CustomMath.NameSpace]::Method(param1, $variableParam, [int]castMeAsIntParam)

Directives can be used to build reusable components. Here is an example of a "user box" component: userBox.js angular.module('simpleDirective', []).directive('userBox', function() { return { scope: { username: '=username', reputation: '=reputation' }, ...

The rep function can be used to repeat a vector in a fairly flexible manner. # repeat counting numbers, 1 through 5 twice rep(1:5, 2) [1] 1 2 3 4 5 1 2 3 4 5 # repeat vector with incomplete recycling rep(1:5, 2, length.out=7) [1] 1 2 3 4 5 1 2 The each argument is especially useful for ex...

This example will show you how to create a Windows Forms Application project in Visual Studio. Create Windows Forms Project Start Visual Studio. On the File menu, point to New, and then select Project. The New Project dialog box appears. In the Installed Templates pane, select "...

Open a text editor (like Notepad), and type the code below: using System; using System.ComponentModel; using System.Drawing; using System.Windows.Forms; namespace SampleApp { public class MainForm : Form { private Button btnHello; // The form's con...

Mesos is a cluster manager aiming for improved resource utilization by dynamically sharing resources among multiple frameworks. It was started at the University of California, Berkeley in 2009 and is in production use in many companies, including Twitter and Airbnb. It became an Apache top-level ...

An Akka MessageDispatcher is what makes Akka Actors "tick", it is the engine of the machine so to speak. All MessageDispatcher implementations are also an ExecutionContext, which means that they can be used to execute arbitrary code, for instance Futures. Every ActorSystem will have a def...

So in case you want to give your Actor a different dispatcher than the default, you need to do two things, of which the first is to configure the dispatcher in your application.conf: my-dispatcher { # Dispatcher is the name of the event-based dispatcher type = Dispatcher # What kind of Exe...

In Common Lisp, if is the simplest conditional construct. It has the form (if test then [else]) and is evaluated to then if test is true and else otherwise. The else part can be omitted. (if (> 3 2) "Three is bigger!" "Two is bigger!") ;;=> "Three is bigger...

docker save -o ubuntu.latest.tar ubuntu:latest This command will save the ubuntu:latest image as a tarball archive in the current directory with the name ubuntu.latest.tar. This tarball archive can then be moved to another host, for example using rsync, or archived in storage. Once the tarball h...

docker-compose run service-name command If, for example, you wanted to run rake db:create in your web service, you'd use the following command: docker-compose run web rake db:create

LOOP has its own IF statement that can control how the clauses are executed: (loop repeat 1000 for x = (random 100) if (evenp x) collect x into evens else collect x into odds finally (return (values evens odds))) Combining multiple clauses in an IF ...

Open a text editor (like Notepad), and type the code below: Imports System.ComponentModel Imports System.Drawing Imports System.Windows.Forms Namespace SampleApp Public Class MainForm : Inherits Form Private btnHello As Button ' The form's constructor: thi...

Over the course of time B-Tree indexes may become fragmented because of updating/deleting/inserting data. In SQLServer terminology we can have internal (index page which is half empty ) and external (logical page order doesn't correspond physical order). Rebuilding index is very similar to dropping...

If your array or array-like object is numeric, that is, if all its elements are numbers, then you can use Math.min.apply or Math.max.apply by passing null as the first argument, and your array as the second. var myArray = [1, 2, 3, 4]; Math.min.apply(null, myArray); // 1 Math.max.apply(null, my...