Docker – How to Create Javascript Runtime using NodeJS

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This article represents information on how to install Javascript runtime in order to compile/interpret JS file for the purpose of testing. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos.
Following are the key points described later in this article:

  • Install NodeJS Runtime with Docker Container
  • Script to Create NodeJS Container
  • Test JS script execution
Many a times, we come across the need to write the Javascript file and run it using a Runtime without the need to test the Javascript code using an HTML page. We could achieve this objective using NodeJS runtime. We shall use Docker to create NodeJS container within which we could write and test our JS files.
Install NodeJS Runtime with Docker Container

Following code could be used to build the NodeJS image:

# Use centos6 base image
FROM    centos:centos6

# Enable Extra Packages for Enterprise Linux (EPEL) for CentOS
RUN     yum install -y epel-release

# Install Node.js and npm
RUN     yum install -y nodejs npm
Script to Create NodeJS Container

Following script (name it as installNode.js) could be used to create NodeJS container:

#!/bin/sh

if [ $# == 0 ]; then
  echo "This script expect container name argument. Example: ./installNode.sh node1"
  exit 100
fi

# Build NodeJS image if it does not exists
#
nb_image="nodejs_base"
nb_df="nodejs_base.df"
if [ `docker images $nb_image | wc -l` -lt 2 ]; then
  echo "Docker Image $nb_image do not exist..."
  echo "Builing docker image $nb_image"
  if [ -f $nb_df ]; then
    docker build -t $nb_image -f $nb_df .
  else
    echo "Can't find Dockerfile $nb_df in the current location"
    exit 200
  fi
fi

docker run -ti -dP --name $1 -v /c/Users:/mnt/Users $nb_image /bin/bash

Execute the above script using following code to start the container with name as “node1”

./installNode.js node1
Test JS File Execution

Login inside the NodeJS container with following code:

docker exec -ti node1 bash

Once logged in, create a sample file, namely hello.js, such as following:

function hello(user) {
    return "Hello, " + user;
}

console.log(hello("Calvin"));

Execute using Node runtime in following way and “Hello, Calvin” will be printed.

node hello.js

 

Ajitesh Kumar
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