From e9ffc1e49998d42f37b39cd23b56b73f7dc0e3da Mon Sep 17 00:00:00 2001 From: Daniel Gasienica Date: Sat, 1 Jun 2013 21:53:22 -0700 Subject: [PATCH] Add Node.js web app example using CentOS --- docs/sources/examples/index.rst | 3 +- docs/sources/examples/nodejs_web_app.rst | 225 +++++++++++++++++++++++ 2 files changed, 227 insertions(+), 1 deletion(-) create mode 100644 docs/sources/examples/nodejs_web_app.rst diff --git a/docs/sources/examples/index.rst b/docs/sources/examples/index.rst index 3a8e01fe03..d017f641b1 100644 --- a/docs/sources/examples/index.rst +++ b/docs/sources/examples/index.rst @@ -1,6 +1,6 @@ :title: Docker Examples :description: Examples on how to use Docker -:keywords: docker, hello world, python, couch, couchdb, redis, ssh, sshd, examples +:keywords: docker, hello world, node, nodejs, python, couch, couchdb, redis, ssh, sshd, examples @@ -16,6 +16,7 @@ Contents: hello_world hello_world_daemon python_web_app + nodejs_web_app running_redis_service running_ssh_service couchdb_data_volumes diff --git a/docs/sources/examples/nodejs_web_app.rst b/docs/sources/examples/nodejs_web_app.rst new file mode 100644 index 0000000000..7c1df83776 --- /dev/null +++ b/docs/sources/examples/nodejs_web_app.rst @@ -0,0 +1,225 @@ +:title: Running a Node.js app on CentOS +:description: Installing and running a Node.js app on CentOS +:keywords: docker, example, package installation, node, centos + +.. _nodejs_web_app: + +Node.js Web App +=============== + +.. include:: example_header.inc + +The goal of this example is to show you how you can build your own docker images +from a parent image using a ``Dockerfile`` . We will do that by making a simple +Node.js hello world web application running on CentOS. + +Create Node.js app +++++++++++++++++++ + +First, create a ``package.json`` file that describes your app and its +dependencies: + +.. code-block:: json + + { + "name": "docker-centos-hello", + "private": true, + "version": "0.0.1", + "description": "Node.js Hello World app on CentOS using docker", + "author": "Daniel Gasienica ", + "dependencies": { + "express": "3.2.4" + } + } + +Then, create an ``index.js`` file that defines a web app using the +`Express.js `_ framework: + +.. code-block:: javascript + + var express = require('express'); + + // Constants + var PORT = 8080; + + // App + var app = express(); + app.get('/', function (req, res) { + res.send('Hello World\n'); + }); + + app.listen(PORT) + console.log('Running on http://localhost:' + PORT); + + +In the next steps, we’ll look at how you can run this app inside a CentOS +container using docker. First, you’ll need to build a docker image of your app. + +Creating a ``Dockerfile`` ++++++++++++++++++++++++++ + +Create an empty file called ``Dockerfile``: + +.. code-block:: bash + + touch Dockerfile + +Open the ``Dockerfile`` in your favorite text editor and add the following line +that defines the version of docker the image requires to build +(this example uses docker 0.3.4): + +.. code-block:: bash + + # DOCKER-VERSION 0.3.4 + +Next, define the parent image you want to use to build your own image on top of. +Here, we’ll use `CentOS `_ (tag: ``6.4``) +available on the `docker index`_: + +.. code-block:: bash + + FROM centos:6.4 + +Since we’re building a Node.js app, you’ll have to install Node.js as well as +npm on your CentOS image. Node.js is required to run your app and npm to install +your app’s dependencies defined in ``package.json``. +To install the right package for CentOS, we’ll use the instructions from the +`Node.js wiki`_: + +.. code-block:: bash + + # Enable EPEL for Node.js + RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm + # Install Node.js and npm + RUN yum install -y npm-1.2.17-5.el6 + +To bundle your app’s source code inside the docker image, use the ``ADD`` +command: + +.. code-block:: bash + + # Bundle app source + ADD . /src + +Your app binds to port ``8080`` so you’ll use the ``EXPOSE`` command to have it +mapped by the docker daemon: + +.. code-block:: bash + + EXPOSE 8080 + +Last but not least, define the command to run your app using ``CMD`` which +defines your runtime, i.e. ``node``, and the path to our app, i.e. +``src/index.js`` (see the step where we added the source to the container): + +.. code-block:: bash + + CMD ["node", "/src/index.js"] + +Your ``Dockerfile`` should now look like this: + +.. code-block:: bash + + + # DOCKER-VERSION 0.3.4 + FROM centos:6.4 + + # Enable EPEL for Node.js + RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm + # Install Node.js and npm + RUN yum install -y npm-1.2.17-5.el6 + + # Bundle app source + ADD . /src + EXPOSE 8080 + CMD ["node", "/src/index.js"] + + +Building your image ++++++++++++++++++++ + +Go to the directory that has your ``Dockerfile`` and run the following command +to build a docker image. The ``-t`` flag let’s you tag your image so it’s easier +to find later using the ``docker images`` command: + +.. code-block:: bash + + docker build -t /centos-node-hello . + +Your image will now be listed by docker: + +.. code-block:: bash + + docker images + + > # Example + > REPOSITORY TAG ID CREATED + > centos 6.4 539c0211cd76 8 weeks ago + > gasi/centos-node-hello latest d64d3505b0d2 2 hours ago + + +Run the image ++++++++++++++ + +Running your image with ``-d`` runs the container in detached mode, leaving the +container running in the background. Run the image you previously built: + +.. code-block:: bash + + docker run -d /centos-node-hello + +Print the output of your app: + +.. code-block:: bash + + # Get container ID + docker ps + + # Print app output + docker logs + + > # Example + > Running on http://localhost:8080 + + +Test +++++ + +To test your app, get the the port of your app that docker mapped: + +.. code-block:: bash + + docker ps + + > # Example + > ID IMAGE COMMAND ... PORTS + > ecce33b30ebf gasi/centos-node-hello:latest node /src/index.js 49160->8080 + +In the example above, docker mapped the ``8080`` port of the container to +``49160``. + +Now you can call your app using ``curl`` (install if needed via: +``sudo apt-get install curl``): + +.. code-block:: bash + + curl -i localhost:49160 + + > HTTP/1.1 200 OK + > X-Powered-By: Express + > Content-Type: text/html; charset=utf-8 + > Content-Length: 12 + > Date: Sun, 02 Jun 2013 03:53:22 GMT + > Connection: keep-alive + > + > Hello World + +We hope this tutorial helped you get up and running with Node.js and CentOS on +docker. You can get the full source code at +https://github.com/gasi/docker-node-hello. + +Continue to :ref:`running_redis_service`. + + +.. _Node.js wiki: https://github.com/joyent/node/wiki/Installing-Node.js-via-package-manager#rhelcentosscientific-linux-6 +.. _docker index: https://index.docker.io/