Docker For Frontend Developers

This is short and simple guide of docker, useful for frontend developers.

Why should you use docker?

Long long back when business needed other application DevOps team would go out and buy a server, without knowing performance requirements of the new apps. This would involve lot of guess work and wastage of capital and resources which could be used for other apps.

Enter Virtual machines or VM, it allowed us to run multiple apps on same servers. but there is a drawback. Every VM needed entire OS to run. Every OS needs CPU, RAM etc to run, it needs patching and licensing, which in turn increases cost and resiliency.

Google started using containers model long time ago to address shortcomings of VM model. Basically what container model means that multiple containers on same host uses same host, freeing up CPU, RAM which could be used elsewhere.

But how does it helps us developers?
It ensures that the working environment is same for all developers and all servers i.e, production, staging and testing

Anyone can setup the project in seconds, no need to mess with config, install libraries, setup dependencies etc.

In simple terms docker is a platform that enables us to develop, deploy, and run applications with containers.
Let’s take a step back, what does container system look like physically and how is it different from VM.

1.1 Difference between VM and docker.

As you can see host and it’s resources are shared in containers but not in Virtual Machine.

With that out of the way, let’s dive.

How to use docker?

For that we need to familiarise ourselves with certain terminology.

1.2 Visualisation of docker images and docker container

Docker image: It is an executable file which contains cutdown operating system and all the libraries and configuration needed to run the application. It has multiple layers stacked on top of each other and represented as single object. A docker image is created using docker file, we will get to that in a bit.

Docker Container: It is a running instance of docker image. there can be many containers running from same docker image.

Containerise simple Node.js App

We would try to containerise very node.js simple app, and create a image:

Your Node.js App

Let’s start by creating folder my-node-app ,

mkdir my-node-app  
cd my-node-app

let ‘s create a simple node server in index.js and add following code there:

//Load express module with `require` directive

var express = require('express')

var app = express()

//Define request response in root URL (/)  
app.get('/', function (req, res) {  
 res.send('Hello World!')  
})

//Launch listening server on port 8081  
app.listen(8081, function () {  
  console.log('app listening on port 8081!')  
})

and save this file inside your my-node-app folder.

Now we create a package.json file and add following code there:

 {

    "name": "helloworld",  
    "version": "1.0.0",  
    "description": "Dockerized node.js app",  
    "main": "index.js",  
    "author": "",  
    "license": "ISC",  
    "dependencies": {  
      "express": "^4.16.4"  
    }

 }

At this point you don’t need express or npm installed in your host, because remember dockerfile handles setting up all the dependencies, lib and configurations.

DockerFile

Let’s create dockerfile and save it inside our my-node-app folder. This file has no extension and is named Dockerfile . Let go ahead and add following code to our dockerfile.

  # Dockerfile  
    FROM node:8  
    WORKDIR /app  
    COPY package.json /app  
    RUN npm install  
    COPY . /app  
    EXPOSE 8081  
    CMD node index.js

Now what we are doing here:

FROM node:8 — pulls node.js docker image from docker hub, which can be found here https://hub.docker.com/_/node/

WORKDIR /app -this sets working directory for our code in image, it is used by all the subsequent commands such as COPY , RUN and CMD

COPY package.json /app -this copies our package.json from host my-node-app folder to our image in /app folder.

RUN npm install — we are running this command inside our image to install dependencies (node_modules) for our app.

COPY . /app — we are telling docker to copy our files from my-node-app folder and paste it to /app in docker image.

EXPOSE 8081 — we are exposing a port on the container using this command. Why this port ? because in our server in index.js is listening on 8081. By default containers created from this image will ignore all the requests made to it.

Build Docker Image

Show time. Open terminal , go to your folder my-node-app and type following command:

 # Build a image docker build -t <image-name> <relative-path-to-your-dockerfile>

    docker build -t hello-world .

This command creates a hello-world image on our host.

-t is used to give a name to our image which is hello-world here.

. is the relative path to docker file, since we are in folder my-node-app we used dot to represent path to docker file.

You will see an output on your command line something like this:

 Sending build context to Docker daemon  4.096kB  
    Step 1/7 : FROM node:8  
     ---> 4f01e5319662  
    Step 2/7 : WORKDIR /app  
     ---> Using cache  
     ---> 5c173b2c7b76  
    Step 3/7 : COPY package.json /app  
     ---> Using cache  
     ---> ceb27a57f18e  
    Step 4/7 : RUN npm install  
     ---> Using cache  
     ---> c1baaf16812a  
    Step 5/7 : COPY . /app  
     ---> 4a770927e8e8  
    Step 6/7 : EXPOSE 8081  
     ---> Running in 2b3f11daff5e  
    Removing intermediate container 2b3f11daff5e  
     ---> 81a7ce14340a  
    Step 7/7 : CMD node index.js  
     ---> Running in 3791dd7f5149  
    Removing intermediate container 3791dd7f5149  
     ---> c80301fa07b2  
    Successfully built c80301fa07b2  
    Successfully tagged hello-world:latest

As you can see it ran the steps in our docker file and output a docker image. When you try it first time it will take a few minutes, but from next time it will start to use the cache and build much faster and output will be like the one shown above. Now, try following command in your terminal to see if your image is there or not :

 # Get a list of images on your host 
    docker images

it should have a list of images in your host. something like this

    REPOSITORY    TAG      IMAGE ID      CREATED         SIZE  
    hello-world   latest   c80301fa07b2  22 minutes ago  896MB

Run Docker Container

With our images created we can spin up a container from this image.

    # Default command for this is docker container run <image-name>  
    docker container run -p 4000:8081  hello-world

This command is used to create and run a docker container.

-p 4000:8081— this is publish flag, it maps host port 4000 to container port 8081 which we opened through expose command in dockerfile. Now all the requests to host port 4000 will be listened by container port 8081.

hello-world — this is the name we gave our image earlier when we ran docker-build command.

You will receive some output like this :

    app listening on port 8081!

If you want to enter your container and mount a bash terminal to it you can run

    # Enter the container
    docker exec -it <container id> /bin/bash

In order to check if container is running or not, open another terminal and type

    docker ps

You should see your running container like this

     CONTAINER ID    IMAGE        COMMAND                  CREATED    
    `<container id>`  hello-world  "/bin/sh -c 'node in…"   11 seconds ago

    STATUS              PORTS                    NAMES  
    Up 11 seconds       0.0.0.0:4000->8081/tcp   some-random-name

It means our container with id <container id> created from hello-world image, is up and running and listening to port 8081.

Now our small Node.js app is completely containerised. You can run http://localhost:4000/ on your browser and you should see something like this:

1.3 Containerised Node.js App

You have containerised your first app.

#docker #javascript

What is GEEK

Buddha Community

Hire Frontend Developers

Create a new web app or revamp your existing website?

Every existing website or a web application that we see with an interactive and user-friendly interface are from Front-End developers who ensure that all visual effects come into existence. Hence, to build a visually appealing web app front-end development is required.

At HourlyDeveloper.io, you can Hire FrontEnd Developers as we have been actively working on new frontend development as well as frontend re-engineering projects from older technologies to newer.

Consult with experts: https://bit.ly/2YLhmFZ

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How long does it take to develop/build an app?

With more of us using smartphones, the popularity of mobile applications has exploded. In the digital era, the number of people looking for products and services online is growing rapidly. Smartphone owners look for mobile applications that give them quick access to companies’ products and services. As a result, mobile apps provide customers with a lot of benefits in just one device.

Likewise, companies use mobile apps to increase customer loyalty and improve their services. Mobile Developers are in high demand as companies use apps not only to create brand awareness but also to gather information. For that reason, mobile apps are used as tools to collect valuable data from customers to help companies improve their offer.

There are many types of mobile applications, each with its own advantages. For example, native apps perform better, while web apps don’t need to be customized for the platform or operating system (OS). Likewise, hybrid apps provide users with comfortable user experience. However, you may be wondering how long it takes to develop an app.

To give you an idea of how long the app development process takes, here’s a short guide.

App Idea & Research

_Average time spent: two to five weeks _

This is the initial stage and a crucial step in setting the project in the right direction. In this stage, you brainstorm ideas and select the best one. Apart from that, you’ll need to do some research to see if your idea is viable. Remember that coming up with an idea is easy; the hard part is to make it a reality.

All your ideas may seem viable, but you still have to run some tests to keep it as real as possible. For that reason, when Web Developers are building a web app, they analyze the available ideas to see which one is the best match for the targeted audience.

Targeting the right audience is crucial when you are developing an app. It saves time when shaping the app in the right direction as you have a clear set of objectives. Likewise, analyzing how the app affects the market is essential. During the research process, App Developers must gather information about potential competitors and threats. This helps the app owners develop strategies to tackle difficulties that come up after the launch.

The research process can take several weeks, but it determines how successful your app can be. For that reason, you must take your time to know all the weaknesses and strengths of the competitors, possible app strategies, and targeted audience.

The outcomes of this stage are app prototypes and the minimum feasible product.

#android app #frontend #ios app #minimum viable product (mvp) #mobile app development #web development #android app development #app development #app development for ios and android #app development process #ios and android app development #ios app development #stages in app development

Developer Career Path: To Become a Team Lead or Stay a Developer?

For a developer, becoming a team leader can be a trap or open up opportunities for creating software. Two years ago, when I was a developer, I was thinking, “I want to be a team leader. It’s so cool, he’s in charge of everything and gets more money. It’s the next step after a senior.” Back then, no one could tell me how wrong I was. I had to find it out myself.

I Got to Be a Team Leader — Twice

I’m naturally very organized. Whatever I do, I try to put things in order, create systems and processes. So I’ve always been inclined to take on more responsibilities than just coding. My first startup job, let’s call it T, was complete chaos in terms of development processes.

Now I probably wouldn’t work in a place like that, but at the time, I enjoyed the vibe. Just imagine it — numerous clients and a team leader who set tasks to the developers in person (and often privately). We would often miss deadlines and had to work late. Once, my boss called and asked me to come back to work at 8 p.m. to finish one feature — all because the deadline was “the next morning.” But at T, we were a family.

We also did everything ourselves — or at least tried to. I’ll never forget how I had to install Ubuntu on a rack server that we got from one of our investors. When I would turn it on, it sounded like a helicopter taking off!

At T, I became a CTO and managed a team of 10 people. So it was my first experience as a team leader.

Then I came to work at D — as a developer. And it was so different in every way when it came to processes.

They employed classic Scrum with sprints, burndown charts, demos, story points, planning, and backlog grooming. I was amazed by the quality of processes, but at first, I was just coding and minding my own business. Then I became friends with the Scrum master. I would ask him lots of questions, and he would willingly answer them and recommend good books.

My favorite was Scrum and XP from the Trenches by Henrik Kniberg. The process at D was based on its methods. As a result, both managers and sellers knew when to expect the result.

Then I joined Skyeng, also as a developer. Unlike my other jobs, it excels at continuous integration with features shipped every day. Within my team, we used a Kanban-like method.

We were also lucky to have our team leader, Petya. At our F2F meetings, we could discuss anything, from missing deadlines to setting up a task tracker. Sometimes I would just give feedback or he would give me advice.

That’s how Petya got to know I’d had some management experience at T and learned Scrum at D.

So one day, he offered me to host a stand-up.

#software-development #developer #dev-team-leadership #agile-software-development #web-development #mobile-app-development #ios-development #android-development

Offshore Software Development - Best Practices

With the rise of globalization and the worldwide lockdown due to the pandemic, most of the work has been done by remote working processes and professionals from their homes. This lockdown has proved the efficiency of remote development and enhanced the trust in offshore software development industry.

To make the most out of the benefits of offshore software development, you should understand the crucial factors that affect offshore development. This is why you should read this guide for the best practices when hiring an offshore software development company. Despite the size and the industry of the business, offshore software development is not beneficial for every entrepreneur in many aspects to make the optimum use of talents in technology across the globe.

Here are some of the top reasons why offshore development is beneficial for your business.

• Offshore development teams can work on flexible timing to provide you with the best possible software development practices.
• Get access to the talents across the world from your home to develop the top of the line software with the help of offshore development companies.
• Assured high quality and next-generation technology expertise with duly NDA signed with respect to the priorities of the business.
• With flexible recruitment models, you can hire the freelance developers, remote development team, or an entire offshore development company with respect to the size of your business.
• Build high-end software applications from one corner of the world by hiring software developers across the world.
• Get immediate access to the best resources without hiring them on a permanent basis.

To avail of all these benefits, you should have clear goals, a list of requirements, and features that are mandatory for your software product.

Here are a few tips to help you find the best offshore software development company. Build a top-notch software application by following the listed best practices.

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Docker Explained: Docker Architecture | Docker Registries

Following the second video about Docker basics, in this video, I explain Docker architecture and explain the different building blocks of the docker engine; docker client, API, Docker Daemon. I also explain what a docker registry is and I finish the video with a demo explaining and illustrating how to use Docker hub

In this video lesson you will learn:

• What is Docker Host
• What is Docker Engine
• Learn about Docker Architecture
• Learn about Docker client and Docker Daemon
• Docker Hub and Registries
• Simple demo to understand using images from registries

#docker #docker hub #docker host #docker engine #docker architecture #api