Try Not To Boil The Ocean

Do you use TDD to help shape your application’s design?  I do, although I’m not as strict as I used to be.  I used to test eeeverything, now, not so much.  I was a fly on the wall during some Agile coaching sessions from “The Dude” at my shop; he kept making a statement during one particular coaching session – “Let’s not try to boil the ocean, ok?”

I know he’s not the first one to say this, it’s a pretty common saying.  The context was around stories, epics, and setting up a story map and making discrete stories that can simply organize work items for the team to work on – small bites, Legos – pick your analogy.  It just allowed for the story map to flow better and to give the team context around what’s next, and what “it” is what’s being accomplished.

I try to do the same thing with TDD – as I’ve mentioned in other blogs, testing the framework isn’t as valuable as testing your own code, right?  I mean, if there’s a bug in a(the) framework you’re using you’re going to find it sooner or later if you are pressing any particular namespace pretty hard.

One thing I also learned from Uncle Bob was that TDD can help you understand a framework – probably not as much as Code Kata, but so TDD helps me understand the namespace(s) I’m working in and keeps the context and responsibilities of the classes tighter and more cohesive.

Moving on…

I started out trying to boil the ocean for the Windows Azure Media Services (WAMS) because I didn’t get how everything was wrapped together and how things were processed.  There’s things you can’t mock, but some things you can.  There are many interface types you can implement to make your own mocking types for quicker tests, and understanding these interfaces once they’re implemented inside your own concrete types helps tell the story of what they’re doing.  Here are a few that I worked with extensively while I was baking my infrastructure classes: IAsset, IJob, and ITask – I got a lot of mileage (and headaches) unraveling and re-wrapping this stuff for my little brain.

Reducing the temperature from 212F (100C) to a light simmer…

I started with the business layer tests, the thought being I’d spin up some fast(er) running tests in that space first, then move into the infrastructure layer(s).  The effect was my business layer tests had too much code in them.  I was building up some of the infrastructure types while I was building the business layer types and tests – not good.  So I stopped and just focused on the infrastructure bits.  Here’s how the infrastructure assemblies looks right now:

infrastructure

infrastructure tests

There’s four separate services I’ve created for interacting with WAMS.  Each service is something you can do with the WAMS portal, and I wanted to break it up like that, the only thing missing is a publishing service that actually tosses the media over the wall and a URL is assigned to the content you’ve uploaded and encoded.

I’m not using an IoC container yet to spin up concrete types for me, so to keep the tests simple for now I’m just building the concrete types by hand.

 

This was all I need to do to keep the infrastructure types from polluting my business unit tests.  Most of these infrastructure tests are bouncing up against WAMS for now, but my business layer test will be using a few mocked out types using the interfaces I mentioned above.  Once the publishing service and the business layer tests are built out I’ll blog those, but now I’ve got to put some thought into how this application is going to use the business layer, so it’s time for a little (more) story mapping.

HTH

oFc

Starting With Another Clean Slate

Starting out with a sample from here, I wanted to build out some reusable libraries I could use with other projects if needed, but focus the focus of the libraries on a new application which can take advantage of Azure’s Media Services.  I also learned a few things from my last application I built, and I want to incorporate those bits into the solution as well.

Spinning Up Some Media Magic

I was looking over some old app designs I shelved last year, they needed some support from something like Windows Azure Media Services, but they weren’t baked last year;  maybe the preview was out when I last looked, not sure.  Recently, I’ve been toying with the idea of getting one of these applications stood up using WAMS now that they’re ready.

I used this chain of posts to get a small harness built and get an understanding of what this stuff does and how it works together to create assets, then encode and stream in various formats, or convert the formats.  The sample code is a bit of a fire house, but the post(s) explain what’s going on with each chunk coming out of the fire-hose.

What I wanted to share is related to a post where I was fighting with a few assembly references and how they were mixed up and giving me a rash.  I asked NuGet for the WAMS bits and here’s what installed:

WAMS.Dependencies

I remember using some of the 1.7 assemblies, but not the 5.1 assemblies;  not a huge thing, but if the other project I was working on last week got mingled with this one, there might be some challenges.

The WAMS stuff looks fun, and its something new for me, I’ve not done much of this stuff except for using OS apps to convert media files from one format to another; so the curve may be steep starting out but yesterday I flattened it a bit and have a working harness that’s using my WA dev account.

HTH / oFc

Refactor and Review

Review.And.Refactor

I’ve started to bring this “spike” to a close since I’ve set out to figure out the stuff I needed to using a few Azure services and got to a point of refactoring.   When I get to this point with a spike, I set out to do the following things listed in the task list you see here.  I’ll step through the why for each of them.

  1. Refactoring for Interfaces – I tend to build up a few concrete types which don’t need to be added to an IoC container for injection, I try not to abuse Unity even though it’s pretty awesome.  Until I find out that maybe a member needs to be injected to reduce a bit of coupling across the solution.  So, I’ll look for these opportunities across the solution and extract an interface and either add it to the container or do some poor man’s injection w/o the container – it just depends on the context of the type’s usage.  I agree, more interfaces are better, even marker interfaces serve a purpose but I try not to go crazy with anything, interfaces included.
  2. Logging – At this point, I know more than I did a few weeks ago and I’ve got a clearer idea of what I want to log.  This time I just need to build up the event source class for the app based on what I learned.  That’s it.  No more, no less.
  3. Magic Strings and Numbers – This one is special. I litter the application with strings and sometimes numbers and this is the best time to go back over the entire solution to pull them out and into something like constants, that’s what worked for this exercise.  I’m walking through all of the code to see if it makes sense, especially the bits that I’ve not seen in a few weeks.  I forget sometimes what I was thinking, and clarifying with a better member or method name is always better than adding comments.  And yes, I’ve got a small battery of tests to fire off after each changeset gets checked in.
  4. Plumbing for cross-cutting stuff – Now that the logging events are done, I need to plant them in the classes that are doing the work.

Not much here, just some habits I’ve been using over the years to keep solutions clean, readable, and hopefully maintainable.

HTH / oFc

Azure SDK and SLAB

Rosetta StoneRight before I skated out of the office to start my four-day Memorial Day weekend I jotted down a few notes to blog about which outlined what worked for me using the P&P Semantic Logging Application Block (SLAB), as well as a few other sticky points while I was trying to stand up couple Windows Azure roles.

It’s really easy to get tangled up with broken builds when you introduce an updated library/dependency into your projects.  And going backwards a few minor versions just feels wrong when you want to “ship” with the something you want to stay current as long as possible.  While NuGet was handy at keeping everything up to date, it did get in the way at times when I need to swap around a few bits.  On a side note, the Package Manager CLI makes removing and adding things a whiz!  I’m still a huge NuGet fan.

I started out with a 4.0 framework solution, then moved it to the 4.5 framework so I keep it at, or start at, 4.5.  There was nothing wrong with 4.0 until I started adding the dependencies in.  For example, the 2.0 Windows Azure (WA) Storage, Runtime, and Configuration bits I installed from the WA site (http://bit.ly/v5MF7m) install v2.0.5.1, and those assemblies ran on top of 4.0 just fine.  This got me through the bulk of the coding to stand the application up.

Then in a previous post I mentioned I wanted to add in some logging pieces and wanted to give SLAB (http://bit.ly/Vh3Umz) a go.  The sample code didn’t work with what I had on my box for some reason, which gave me a clue I might have some depedency issues coming at me with my code.  The P&P code was easy enough to read through but the namespaces had a few changes at RTW time that I needed to work around, and was expected.

In addition to this, I had to work around issues between WindowsAzure.Storage and the MS.Data.Edm, MS.Data.OData, and System.Spatial assemblies.  I started out satisfying the dependencies with using v5.0.2.0 for them, but *really* wanted to make the latest, v5.4, work, but most of the blog posts I read through confirmed v5.0.2.0 was the way to go.  So the final fall back to get everything happy was to use v5.2 for the Edm, OData, and Spatial assemblies.    Then I learned of the (v5.0.2.0) Edm, OData, and Spatial dependencies.

Inside the SLAB reference application, the console application project took a dependency on an earlier version of Edm, OData, and Spatial and I didn’t want to go that far back – stuff should just work, right?  And it finally did. The logging pieces weren’t throwing anything, but they weren’t working.  The table used to persist the logging entries wasn’t getting built (if it didn’t exist) inside local table storgae, so nothing was being logged.

The answer was to use the Edm, OData, and Spatial v5.2.0.0 assemblies. Bingo!  Everything was firing, and all my tests were still passing so it was very green day once I got all of the zen sorted out in my assembly references.

Below is a list of assemblies with their dependencies sans the ones that come OOTB; hopefully this can help someone bumping into this as well.

HTH / oFc

WebRole (MVC4) Project

  • Microsoft.Practices.EnterpriseLibrary.Common v6.0
  • Microsoft.Practices.EnterpriseLibrary.Logging v6.0
  • Microsoft.Practices.Unity v3.0
  • Microsoft.Practices.Unity.Configuration v3.0
  • Microsoft.WindowsAzure.Storage v2.0.0.0
  • Microsoft.WindowsAzure.StorageClient v1.7.0.0
  • Unity.MVC4 v.1.1.0.0

WorkRole Project

  • Microsoft.Practices.Unity v3.0
  • Microsoft.Practices.Unity.Configuration v3.0
  • Microsoft.Data.Edm v5.2.0.0
  • Microsoft.Data.OData v5.2.0.0
  • System.Spacial v5.2.0.0
  • Microsoft.ServiceBus v1.7
  • Microsoft WindowsAzure.Configuration v1.8
  • Microsoft WindowsAzure.Runtime v1.8
  • Microsoft WindowsAzure.Storage v1.8
  • Microsoft WindowsAzure.StorageClient v1.7

Infrastructure Project

  • Microsoft.Practices.EnterpriseLibrary.SemanticLogging  v1.0
  • Microsoft.Practices.EnterpriseLibrary.SemanticLogging.WindowsAzure  v1.0
  • Microsoft.ServiceBus v1.7
  • Microsoft WindowsAzure.Configuration v1.7
  • Microsoft WindowsAzure.Runtime v1.7
  • Microsoft WindowsAzure.Storage v1.7
  • Microsoft.ServiceBus v1.7

Table Storage Hiccups

So, like most of us, I thought hooking up table storage would be easy.  Turns out, it’s not if like to keep up with the latest and greatest support libraries.

The first hiccup came when I tried to connect to my local storage service (UseDevelopmentStorage=true).  Well, now you need to specify the URI that points to the local storage emulator and like the blog post author states, “it just magically works”

Now that I had the table sitting there, the next hiccup came when I asked my table service context to build the table if it doesn’t exist.  This one was kind of bad, not something I expected.  First I used the Azure SDK library my exception told me I needed, in this case Microsoft.Data.OData (v5.2.0.0).    There’s a newer version of it as well, v.5.4.0.0, that didn’t work either even with an assembly binding redirect.  I installed v5.4 with NuGet and then had to uninstall it manually by clearing out the package.config entries and dropping the references.  Then using the Package Manager Console I installed v.5.0.2.0 instead w/o the binding redirect and it worked.

The last hiccup was getting the entities to insert into the table.  You can find more about CRUD here, and Table Storage CRUD operations here.  A side note on that embedded link, it discusses versions 1.7 and 2.0 – yesterday I was looking at 1.7, not 2.0 so check which form of the page you are looking at before you start coding.

My partition key was missing and the row key and the timestamp properties were null.  I read that the table client took care of this for me, so I used DateTime.UtcNow for a default property, and fixed up my extension method that gen’d my TableEntity for me.  That error came in the form of [ The remote server returned an error: (400) Bad Request ].

Here are the links I eventually found that bailed me out today.  All the code is working and I added a few more guard statements to do some additional state checks before the CRUD bits fire.  Hopefully, the blob storage stuff is ironed out implicitely as well with all of this dependency churn today.

HTH / oFc

Differences between Azure Storage Client Library 1.7 and 2.0

If you decide to use v5.0.2.0 read this.

What Azure allows inside a table entity during CRUD operations

How to use the Table Storage Service

What Happens When It Stops Raining?

sunnyday

When we notice our cloud has stopped raining, it’s time to take a look under the hood to see what happened?  Or, is there a better place to look before we raise the hood?  A few questions to ask:

1) Was it something I did?

2) Was it something that happened inside one of the Azure instances?

3) Did the application run out of work?

4) Where can I look to see what was going on when it stopped?

Only you can answer the first question.  If all of your tests aren’t, or weren’t passing, and promoted something to a production instance you might be able to answer this fairly easily.

The second question assumes you’ve can get to your management portal and look at the analytics surfaced by Azure.  There might have been, or might be, a problem with one or more of your instances restarting.  I’ve never seen either of my instances stay down after a restart unless there was an unhandled exception getting tossed around.  Usually I find these problems in the local dev fabric before I promote.  Sometimes I don’t though, so on a few occasions even though my tests were passing I had missed some critical piece of configuration that my local configuration had, and the cloud config was missing.  I call this PIBKAC – problem is between keyboard and chair.  Usually the analytics are enough to tell you if there were problems.  And from there you can fix configuration if needed, or restart your instances or other Azure feature you’ve got tied to the application.

The third question is kind of a sunny day scenario where the solution is going what its supposed to in a very performant way.  However, sometimes ports can get ignored b/c of a configuration issue like I mentioned prior as one example.  If you’ve been storing your own health monitoring points you can probably tell if your application has stopped listening for new requests, or simply just can’t process anything.

The fourth question talks about having something that’s looking around the instance(s) and capturing some of your system health points: how many messages am I receiving and trying to process; how quickly am I processing the incoming messages; are there any logs that can tell me what was going on when it stopped raining.

I’ve been using Enterprise Library from the PnP team for >6 years and I still love the amount of heavy lifting it does for me.  The wire-ups are usually easy and straightforward and the support behind each libary drop is constant and focused.  Recently Enterprise Libary 6 dropped with a bit of overhauling to target 4.5 among other things, and here’s a blog post by Soma that discusses a few at a high-level.

I’ve used the Data and Logging Application Blocks, as well as Unity successfully.  I had recently started wiring my solution to use the Azure Diagnostics listener to capture some of the diagnostic events, particularly instance restarts from configuration changes.  Now, I think/hope I can use the logging application block to wire all of my logging events and push them to something simple like blob or table storage.

I’ve never like a UI that I have to open up and look through, it just makes my eyes tired and its annoying – I’d like to have something a little more easier to lookup fatal and critical logs first then go from there.  PowerShell (PS) looks cool and fitting for something like this, and I can probably do something quick and dirty from my desktop to pull down critical, fatal, or warning logs but I’m not a PS junkie.  But it would make for an interesting exercise to get some PS on me.  Oh, on a side not I picked up this book to (re)start my PS journey and so far it’s been worth the price I paid.  Some of the EntLib docs mentioned pushing data to Azure storage so I may just start there to see if this can work.

Here’s the doc and code downloads if you want to take a look around.

HTH /oFc