Azure WebJobs In .NET Core – Part 3

This is part 3 of a series on getting up and running with Azure WebJobs in .NET Core. If you are just joining us, it’s highly recommended you start back on Part 1 as there’s probably some pretty important stuff you’ve missed on the way.

Azure WebJobs In .NET Core

Part 1 – Initial Setup/Zip Deploy
Part 2 – App Configuration and Dependency Injection
Part 3 – Deploying Within A Web Project and Publish Profiles
Part 4 – Scheduled WebJobs
Part 5 – Azure WebJobs SDK

Deploying Within A Web Project

So far in this series we’ve been packaging up our WebJob as a stand alone service and deploying as a zip file. There’s two problems with this approach.

• We are manually having to upload a zip to the Azure portal
• 9 times out of 10, we just want to package the WebJob with the actual Website, and deploy them together to Azure

Solving the second issue actually solves the first too. Typically we will have our website deployment process all set up, whether that’s manual or via a build pipeline. If we can just package up our WebJob so it’s actually “part” of the website, then we don’t have to do anything special to deploy our WebJob to Azure.

If you’ve ever created an Azure WebJob in .NET Framework, you know in that eco system, you can just right click your web project and select “Add Existing Project As WebJob” and be done with it. Something like this :

Well, things aren’t quite that easy in the .NET Core world. Although I wouldn’t rule out this sort of integration into Visual Studio in the future, right now things are a little more difficult.

What we actually want to do is create a publish step that goes and builds our WebJob and places it into a particular folder in our Web project. Something we haven’t jumped into yet is that WebJobs are simply console apps that live inside the “App_Data” folder of our web project. Basically it’s a convention that we can make use of to “include” our WebJobs in the website deployment process.

Let’s say we have a solution that has a website, and a web job within it.

What we need to do is edit the csproj of our website project. We need to add something a little like the following anywhere within the <project> node :

<Target Name="PostpublishScript" AfterTargets="Publish">
    <Exec Command="dotnet publish ..\WebJobExamples.WebJobExample\ -o $(ProjectDir)$(PublishDir)App_Data\Jobs\continuous\WebJobExample" />
</Target>

What we are doing is saying when the web project is published, *after* publishing, also run the following command.

Our command is a dotnet publish command that calls publish on our webjob, and says to output it (signified by the -o flag) to a folder in the web projects output directory called “App_Data\Jobs\continuous\WebJobExample”.

Now a quick note on that output path. As mentioned earlier, WebJobs basically just live within the App_Data folder within a website. When we publish a website up to the cloud, Azure basically goes hunting inside these folders looking for webjobs to run. We don’t have to manually specify them in the portal.

A second thing to note is that while we are putting it in the “continuous” folder, you can also put jobs inside the “triggered” folder which are more for scheduled jobs. Don’t worry too much about this for now as we will be covering it in a later post, but it’s something to keep in mind.

Now on our *Website* project, we run a publish command : dotnet publish -c Release . We can head over to our website output directory and check that our WebJob has been published to our web project into the App_Data folder.

At this point, you can deploy your website publish package to Azure however you like. I don’t want to get too in depth on how to deploy the website specifically because it’s less about the web job, and more about how you want your deploy pipeline to work. However below I’ll talk about a quick and easy way to get up and running if you need something to just play around with.

Deploying Your Website And WebJob With Publish Profiles

I have to say that this is by no means some enterprise level deployment pipeline. It’s just a quick and easy way to validate your WebJobs on Azure. If you are a one man band deploying a hobby project, this could well suit your needs if you aren’t deploying all that often. Let’s get going!

For reasons that I haven’t been able to work out yet, the csproj variables are totally different when publishing from Visual Studio rather than the command line. So we actually need to edit the .csproj of our web project a little before we start. Instead of :

<Exec Command="dotnet publish ..\WebJobExamples.WebJobExample\ -o $(ProjectDir)$(PublishDir)App_Data\Jobs\continuous\WebJobExample" />

We want :

<Exec Command="dotnet publish ..\WebJobExamples.WebJobExample\ -o $(PublishDir)App_Data\Jobs\continuous\WebJobExample"   />

So we remove the $(ProjectDir)  variable. The reason is that when we publish from the command line, the $(PublishDir)  variable is relative, whereas when we publish from Visual Studio it’s an absolute path. I tried working out how to do it within MSBuild and have conditional builds etc. But frankly, you are typically only ever going to build one way or the other, so pick whichever one works for you.

If you head to your Azure Web App, on the overview screen, you should have a bar running along the top. You want to select “Get Publish Profile” :

This will download a .publishsettings file to your local machine. We are going to use this to deploy our site shortly.

Inside Visual Studio. Right click your website project, and select the option to Publish. This should pop up a box where you can select how you want to publish your website. We will be clicking the button right down the bottom left hand corner to “Import Profile”. Go ahead and click it, and select the .publishsettings file you just downloaded.

Immediately Visual Studio will kick into gear and push your website (Along with your WebJob) into Azure.

Once completed, we can check that our website has been updated (Visual Studio should immediately open a browser window with your new website), but on top of that we can validate our WebJob has been updated too. If we open up the Azure Portal for our Web App, and scroll down to the WebJob section, we should see the following :

Great! We managed to publish our WebJob up to Azure, but do it in a way that it just goes seamlessly along with our website too. As I mentioned earlier, this isn’t some high level stuff that you want to be doing on a daily basis for large projects, but it works for a solo developer or someone just trying to get something into Azure as painlessly as possible.

Verifying WebJob Files With Kudu

As a tiny little side note, I wanted to point out something if you ever needed to hastily change a setting on a WebJob on the fly, or you needed to validate that the WebJob files were actually deployed properly. The way to do this is using “Kudu”. The name of this has sort of changed but it’s all the same thing.

Inside your Azure Web App, select “Advanced Tools” from the side menu :

Notice how the icon is sort of a “K”… Like K for Kudu… Sorta.

Anyway, once inside you want to navigate to Debug Tools -> CMD. From here you can navigate through the files that actually make up your website. Most notably you want to head along to /site/wwwroot/App_Data/ where you will find your WebJob files. You can add/remove files on the fly, or even edit your appsettings.json files for a quick and dirty hack to fix bad configuration.

What’s Next?

So far all of our WebJobs have printed out “Hello World!” on repeat. But we can actually “Schedule” these jobs to run every minute, hour, day, or some combination of the lot. Best of all, we can do all of this with a single configuration file, without the need to write more C# code! You can check out Part 4 right here!