Experimenting with Azure CDN

With the gradual piecing together of the Lego bricks forming the slow move over of the Frog & Pencil website to a more managed approach (building of a custom CMS and an all-around better ASP.NET MVC architecture) I thought it would be interesting to document the move over of Frog & Pencil images to a CDN. I was inspired to give this a go after watching Scott Hanselman make the switch for his podcast site images and other Azure Friday videos, as documented here:

Scott Hanselman lifting and shifting images over to a CDN.
Azure CDN with Akamai.

It seemed like a relatively painless process and is a step in the right direction for our site as a whole; so, let’s give it a go!

NOTE: A short way into this post I realised that I was making a few missteps. This is cool, I think, as I would rather document the journey I took with the mistakes listed, to be honest – #KeepingItReal! However, for sanity (mine and yours) I’ll specify the ‘correct’ order of events that you should follow here that you can marry up with the ramblings below:

  1. Sign in to the Azure Portal.
  2. Create a storage container, if you don’t already have one.
  3. Download and utilise a storage explorer application (such as Azure Storage Explorer).
  4. Create a CDN Profile and CDN endpoint (that ties explicitly to your storage container, in this instance).
  5. Go to your DNS settings and generate a CNAME property, mapping a custom domain to your CDN if you wish to.
  6. Optionally, learn how to programmatically interact with your storage container.

Azure Portal – First Steps (documenting the journey)

First things first, we must hop on over to the Azure Portal. I searched the marketplace for ‘CDN’ and clicked create in the right-hand pane, as shown:

Creating a CDN

Creating a CDN.

The next phase involves configuring a CDN profile. The profile needs to be given a name and should be attached to an Azure Subscription. I’ve created a new Resource Group, by specifying a name for it, but it is possible to select an existing one for use here. There are some guidelines surrounding Resource Groups, such as items within a group should share the same lifecycle; more details can be found within this handy documentation article, read away!

The Azure CDN service is, of course, global but a Resource Group location must be set, which governs where resource metadata is ultimately stored. This could be an interesting facet to consider if there are particular compliance considerations regarding the storage of information and where it should be placed. I’m going with West Europe either way; a nice, easy choice this time around.

As for pricing, I have decided to head down the Akamai route, using the Standard Akamai pricing tier. I will have to see how this ultimately pans out cost wise over time, but it seems reasonable:

Azure CDN Provider Pricing

Azure CDN Provider Pricing.

At this point, we can explicitly create a CDN endpoint (where resources will be ultimately exposed). The endpoint has a suffix of ‘.azureedge.net’ and I’ve simply specified the first part of our domain, ‘frogandpencil’ as the prefix.

This is where I hit a bit of a revelation with the ‘Origin Type’ drop down. You can select from Storage, Cloud service, Web app or Custom origin (which is cool!), of which I want to use Storage. After selecting this I can pick an ‘Origin hostname’. The light bulb moment here, for me, is that I should have created a storage container first! I’d watched enough videos to have dodged this little problem, but I still managed to stumble…all part of the learning process πŸ˜‰

So… Let’s Create a Storage Container

Back to the market place then. The obvious pick seems to be ‘Storage account – blob, file, table, queue’, so I’ve gone ahead and clicked create here:

Setup Azure Storage.

Setup Azure Storage.

When creating the storage account there are a fair few options to consider, a good number that read as if they will impact pricing. I had to use the documentation found here to make choices. I settled on the setup described here (for images, and as the site isn’t yet using https, I’ve gone with the secure transfer feature being disabled – one for review in the future):

As an overview, the guidance suggests the use of the ‘Resource manager’ type of ‘Deployment model’ for new applications. There doesn’t seem to be a penalty for using the ‘StorageV2’ ‘Account kind’, which extends the types that can be stored outside of just blob data, so that is what I am going for.

Performance wise, the ‘standard’ option seems like an acceptable setting at the moment and for the kind of data I’ll be storing (images for now, and possibly other static content later down the line) I can opt out of any geo-redundant replication options. In the event of resource downtime, I can easily switch to the use of resources local to the website. Plus, there will not be any data being lost really, all easily rebuilt and recoverable.

As for the ‘Access tier’, I’m heading down the ‘Hot’ route as images will be accessed quite frequently (we have the CDN to consider here so I might tinker later on down the line).

I then pick a Subscription, give the Resource Group a name and select my region of choice before continuing.

I then get a new blade on the dashboard (which took a minute to create) and, on accessing, am presented with the following:

Storage Setup.

Storage Setup.

Managing the Storage Container

The first and perhaps most obvious choice for managing and actually getting some content up into the storage container is the Azure Storage Explorer, which I’ll be downloading and using.

After a painless install process, you should see the following, where you will be asked to connect to Azure Storage:

Connect to Azure Storage.

Connect to Azure Storage.

I simply used my Azure account sign in details here. I did notice however that the Azure Portal does expose, under ‘Access Keys’ (within the storage container dashboard), keys and connection strings. I’m assuming this is for other kinds of, including programmatic, access; which I’ll give a go I think as part of this post (as a wee bonus).

I used the right-click context menu to create a new container called ‘images’ and then used the upload button to push up a test image:

Azure Storage Explorer Upload Image.

Azure Storage Explorer Upload Image.

Again, against the container I used the right-click context menu to select ‘Set Public Access Level…’, which I’ve set as follows to allow public access to the blob data but not the container:

Container Public Access Setup.

Container Public Access Setup.

I now have a blob container with a single image in it with appropriate access rights configured. The question is can I access the image in its current state? We’re looking pretty good from what I can see.

Successful Access.

Successful Access.

Adding a custom domain

Next up, I plan on adding a custom domain to the storage account. To do this, I access the ‘Custom domain’ option as shown here:

Register Custom Domain.

Register Custom Domain.

I followed option 1 as listed here and created a CNAME record to map frogandpencilstorage.blob.core.windows.net to images.frogandpencil.com (I’m happy to wait for this to propagate).

Register images.frogandpencil.com.

Register images.frogandpencil.com.

Once the CNAME record is created you simply have to place your target URL in the text box provided and hit save.

New CNAME property.

New CNAME property.

Lastly, let’s take it for a spin and see whether we can access the image in the storage container via the custom URL…and voila:

Custom Domain Active.

Custom Domain Active.

Back to the CDN bit!

We’ve come full circle! With a storage container in place I can now use that to feed a configured CDN. Consequently, I backtracked and followed the previously listed steps being sure to select my ‘Origin hostname’ to point to the newly created storage container:

CDN Profile & Endpoint Configuration.

CDN Profile & Endpoint Configuration.

On clicking create it takes a short time for the CDN to be configured.

So, what do I do now

Looking through the videos I made another discovery. This is where I want to adjust the previously created CNAME property (that I setup for the storage container) and hook this up to the CDN endpoint instead. The portal exposes custom domain mapping for a CDN much like for a storage container:

Change CNAME to map to CDN.

Change CNAME to map to CDN.

Portal CDN Custom Domain Mapping.

Portal CDN Custom Domain Mapping.

Again, I had to wait a short time for the CNAME property change to propagate but, after that, I was all set. I then spent a little time verifying that the CDN was up and running. There are quite a few optimisation options including the ability to set a custom ‘Origin path’ (such as ‘images’) but I’m leaving these be for the time being.

The Bonus Section – Programmatically Add Items to Azure Storage

As promised, this next section discusses (in a very bare bones fashion) what is required to write to an Azure storage container. I’ve created a stub Console Application to get running with and the process itself is simple (not considering errors, existence checks and threading, of course!).

You need to:

  1. Reference the WindowsAzure.Storage NuGet package.
  2. Add a reference to System.Configuration (if you want to put connection strings, folder paths and container names in configuration files and read them out).
  3. Then simply follow the code outlined below to get started.

In my test setup, the ‘SourceDirectory’ is looking at ‘C:\test-files\’ (contains just images) and the ‘TargetContainer’ is called ‘images’, as per my earlier configuration. The connection string can be obtained from the Azure Portal, under ‘Storage Account > Settings > Access Keys’.

Test Files ready for upload.

Test Files.

Storage Access Keys.

Storage Access Keys.

The App.config for the test application is structured like this, with the connection string being set to the correct value as per the information found in the Azure Portal.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
  <connectionStrings>
    <add name="FrogAndPencilStorageConnection" connectionString="[OBTAINED_FROM_THE_AZURE_PORTAL]" />
  </connectionStrings>
  <appSettings>
    <add key="SourceDirectory" value="C:\test-files\"/>
    <add key="TargetContainer" value="images"/>
  </appSettings>
</configuration>

Then, finally, the actual test code which…

  • Attempts to connect to the storage container creating a CloudStorageAccount object, based on the connection string information supplied.
  • Then uses the CloudStorageAccount object to get create a new CloudBlobContainer object (based on the container name stored in the configuration settings).
  • Finally, utilise this CloudBlobContainer, along with information about the files to process, to actually perform the upload.
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;

namespace WriteToAzureStorageTestApp
{
    /// <summary>
    /// Test application for writing to Azure Storage.
    /// Basic, test code only (throwaway code).
    /// </summary>
    internal class Program
    {
        #region Main (Entry Point) Method

        /// <summary>
        /// Main entry point method for this console application.
        /// </summary>
        /// <param name="args">Optional input arguments.</param>
        private static void Main(string[] args)
        {
            DemoWritingToAzureStorage();
        }

        #endregion Main (Entry Point) Method

        #region Private Static Methods

        /// <summary>
        /// Private static demo method illustrating how to upload to Azure Storage.
        /// </summary>
        private static void DemoWritingToAzureStorage()
        {
            // First use the FrogAndPencilStorageConnection connection string (for Azure Storage) to obtain a CloudStorageAccount, if possible
            CloudStorageAccount.TryParse(ConfigurationManager.ConnectionStrings["FrogAndPencilStorageConnection"].ConnectionString, out CloudStorageAccount storageAccount);
            if (storageAccount != null)
            {
                // We have a CloudStorageAccount...proceed to grab a CloudBlobContainer and attempt to upload any files found in the 'SourceDirectory' to Azure Storage
                Console.WriteLine("Obtaining CloudBlobContainer.");

                CloudBlobContainer container = GetCloudBlobContainer(storageAccount);

                Console.WriteLine("Container resolved.");

                Console.WriteLine("Obtaining files to process.");

                List<string> filesToProcess = Directory.GetFiles(ConfigurationManager.AppSettings["SourceDirectory"]).ToList();

                UploadFilesToStorage(container, filesToProcess);
            }

            Console.WriteLine("Processing complete. Press any key to exit...");
            Console.ReadLine();
        }

        /// <summary>
        /// Private static utility method that obtains a CloudBlobContainer
        /// using the container name stored in app settings.
        /// </summary>
        /// <param name="storageAccount">The cloud storage account to retrieve a container based on.</param>
        /// <returns>A fully instantiated CloudBlobContainer, based on the TargetContainer app setting.</returns>
        private static CloudBlobContainer GetCloudBlobContainer(CloudStorageAccount storageAccount)
        {
            CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

            return blobClient.GetContainerReference(ConfigurationManager.AppSettings["TargetContainer"]);
        }

        /// <summary>
        /// Private static utility method that, using a CloudBlobContainer, uploads the
        /// files passed in to Azure Storage.
        /// </summary>
        /// <param name="container">A reference to the container to upload to.</param>
        /// <param name="filesToProcess">The files to upload to the container.</param>
        private static void UploadFilesToStorage(CloudBlobContainer container, List<string> filesToProcess)
        {
            // Process each file, uploading it to storage and deleting the local file reference as we go
            filesToProcess.ForEach(filePath =>
            {
                Console.WriteLine($"Processing and uploading file from path '{ filePath } (then deleting)'.");

                // Upload the file based on name (note - there is no existence check or guarantee of uniqueness - production code would need this)
                container.GetBlockBlobReference(Path.GetFileName(filePath)).UploadFromFile(filePath);

                RemoveFileFromLocalDirectory(filePath);
            });
        }

        /// <summary>
        /// Private static utility method for deleting a file.
        /// </summary>
        /// <param name="filePath">The file path (full) to delete based upon.</param>
        private static void RemoveFileFromLocalDirectory(string filePath)
        {
            // Only attempt the delete if the file exists
            if (File.Exists(filePath))
            {
                File.Delete(filePath);
            }
        }

        #endregion Private Static Methods
    }
}
Test Upload Application Running.

Test Upload Application Running.

Test Files Uploaded.

Test Files Uploaded.

There you have it; a rather around the houses and off the wall tour of setting up an Azure storage container and then linking this to an Azure CDN. Plenty of images still need to be brought over into the new storage container (and a few code changes to boot), but I feel like I am on a pilgrimage to a better place. I hope this proves useful nonetheless and, until the next time, happy coding!

Addendum

After a further play I realised that the C# example I’d knocked up was not setting the content type correctly on upload, as follows:

Incorrect Content Type.

Incorrect Content Type.

To this end, I adjusted the UploadFilesToStorage method to set the content type on a CloudBlockBlob before the upload is triggered, as illustrated here:

/// <summary>
/// Private static utility method that, using a CloudBlobContainer, uploads the
/// files passed in to Azure Storage.
/// </summary>
/// <param name="container">A reference to the container to upload to.</param>
/// <param name="filesToProcess">The files to upload to the container.</param>
private static void UploadFilesToStorage(CloudBlobContainer container, List<string> filesToProcess)
{
	CloudBlockBlob blockBlob;

	// Process each file, uploading it to storage and deleting the local file reference as we go
	filesToProcess.ForEach(filePath =>
	{
		Console.WriteLine($"Processing and uploading file from path '{ filePath } (then deleting)'.");

		// Upload the file based on name (note - there is no existence check or guarantee of uniqueness - production code would need this)
		blockBlob = container.GetBlockBlobReference(Path.GetFileName(filePath));

		// Correctly configure the content type before uploading
		blockBlob.Properties.ContentType = "image/jpg";

		blockBlob.UploadFromFile(filePath);

		RemoveFileFromLocalDirectory(filePath);
	});
}

You should then see items with the correct content type in the container:

Correct Content Type.

Correct Content Type.

To access images via the custom domain, essentially my CDN, I had to ‘purge’ it also at this point.

Again, happy coding.

Looking for a Lighthouse

Happy New Year all and I truly hope you all enjoyed a terrific festive period.

As a little weekend treat, I decided to pick myself up a copy of the ‘net’ magazine, mainly due to the included feature articles on which web development and design tools are ‘en-flique’ (that one is for Claire; a trip to the urban dictionary is in order) for 2018. There are also some amazing looking articles discussing things like colour palette choices, and tools that assist in creating them, which should prove handy as I will be looking to potentially change up the Frog & Pencil website a little as I craft a fully functional CMS this year; something that has been well overdue.

As a quick aside, I’ve decided to check out Google’s own automated page analysis tool, Lighthouse. This can run performance and accessibility analysis on public or password protected sites. Information for getting started can be found here.

I’m opting to run this within Chrome development tools, but you can run this from the command line or as a Node module if you prefer (which allows you to hook this into a continuous integration setup, which could be incredibly useful).

Up to this point, I have been using YSlow as a web page dissection tool, but I’m happy to bust out an alternative to keep things interesting.

So, what kind of feedback does the tool provide and how does it present it? I’ll run this against the Frog & Pencil homepage and show you the results (no matter how bad they turn out, I’ll be honest!). When using Chrome you just need to inspect the audits tab, within Chrome development tools (accessed via F12 or Ctrl+Shift+I, on windows), to get up and running as follows:

Lighthouse via the Audits Tab.

Audits Tab.

On clicking ‘Perform an audit…’ you be presented with options as below (I’ll leave them all checked for this particular test run):

Audit Options for Lighthouse.

Audit Options.

The report is, on first inspection, very detailed and, as you can see, I have a fair bit of work to do (although I’m happy with the accessibility rating at least). The report is downloadable using the highlighted button:

Lighthouse Report Header.

Lighthouse Report Header.

The tests performed also appear to be more strict that the YSlow V2 test, which is nice to see:

YSlow V2 Test.

YSlow V2 Test.

There have been some surprising opportunities for improvement highlighted. I’ve long known that I should switch out the entire site to run over https and when the site is overhauled I intend to make better use of bundling for static files and will consider the use of a CDN. I have plenty of work to do with image compression also.

Here are a few things that really caught my attention:

1) How poor the site ran under simulated 3G speeds:

Simulated 3G Speeds

Simulated 3G Speeds.

2) The scale of the improvements still to be made by reducing render blocking scripts/stylesheets (a boo boo that I should really be covering) and image management:

Performance Improvement Opportunities.

Performance Improvement Opportunities.

3) The report highlighted that I was using libraries with known vulnerabilities and that I have left in code that was writing errors to the console (doh!):

Third Party Libraries.

Third Party Libraries.

This does bring into focus the core need of revisiting the website this year and giving it a thorough tune-up, as opportunities towards the end of last year were at a premium. All in all, if you’ve not used Lighthouse yet I would suggest giving it a look; especially as it takes seconds to run. I’ll be working my way through the highlighted areas in the report in the meantime!

All the best πŸ˜‰

Modernizr – Detecting Screen Size Changes

A brief titbit today, but one I felt was worth sharing and has come in handy for work/personal projects recently for me.

I’ve had a couple of requirements to gracefully show/hide and adjust web page layouts based on screen sizes (and screen re-sizing). I came across the following solution which works pretty damn well.

First things first, you’ll need Modernizr, which is in essence a feature detection javascript library. In this case, however, I’m using other features to react to browser re-sizing. There’s a few options for obtaining this for your projects but, as far as Visual Studio is concerned, I used the Package Manager Console using the following command:

Install Modernizr via the Package Manager Console.

Install Modernizr via the Package Manager Console.

Once installed, we end up with the javascript library included under the default Scripts folder:

Modernizr in Scripts Folder.

Modernizr in Scripts Folder.

On installing the package, as I didn’t specify a specific version, I end up with the following declaration in my packages.config file (part of my ASP.NET MVC project) – 2.8.3 denoting the most recent version:

<package id="Modernizr" version="2.8.3" targetFramework="net452" />

Next up, simply chuck the usual script element into your page to reference the library – Now you’re all set!

<script src="~/Scripts/modernizr-2.8.3.js" type="text/javascript"></script>

The following snippet shows the basic scaffolding code to start capturing screen size changes (I’ve declared this code in my jQuery document ready function). The doneResizing function is tied to the window resize event and you can easily use Modernizr to read and react to the screen size as required:

//Function to react to screen re-sizing
function doneResizing() {
	if (Modernizr.mq("screen and (min-width:868px)")) {
		//Implement jQuery/JS to handle a larger screen (i.e. Laptops/Desktops). In my case adding/removing a class to show/hide elements
	}
	else if (Modernizr.mq("screen and (max-width:867px)")) {
		//Implement jQuery/JS to handle a smaller screen (i.e. Tablets/Mobiles). In my case adding/removing a class to show/hide elements
	}
}

//Call doneResizing on re-size of the window
var id;
$(window).resize(function () {
	clearTimeout(id);
	id = setTimeout(doneResizing, 0);
});

//Call doneResizing on instantiation
doneResizing();

Currently, I’m using this to show/hide element containers within a web page based on screen size (and apply/remove a few classes on the fly to ensure everything looks as it should on desktop, tablet and mobile displays). It appears to function very well, one worth investigating for your own projects. See here for the original Stack Overflow article detailing ideas surrounding this concept (including other CSS related solutions).

Bye for now!