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At Build the Azure team launched a new service called Azure Static Web Apps in preview. This service is tailored for scenarios that really work well when you have a static web site front-end and using things like serverless APIs for your communication to services/data/etc. You should read more about it here: Azure Static Web Apps .

Awesome, so Blazor WebAssembly (Wasm) is a static site right? Can you use this new service to host your Blazor Wasm app? Let’s find out!

NOTE: This is just an experiment for me.  This isn’t any official stance of what may come with the service, but only what we can do now with Blazor apps.  As you see with Azure Static Web Apps there is a big end-to-end there with functions, debug experience, etc.  I just wanted to see if Blazor Wasm (as a static web app) could be pushed to the service.

As of this post the service is tailored toward JavaScript app development and works seamlessly in that setup. However, with a few tweaks (for now) we can get our Blazor app working. First we’ll need to get things setup!

Setting up your repo

The fundamental aspects of the service are deployment from your source in GitHub using GitHub Actions. So first you’ll need to make sure you have a repository on GitHub.com for your repository. I’m going to continue to use my Blazor Wasm Hosting Sample repo (which has different options as well to host Wasm apps) for this example. My app is the basic Blazor Wasm template, nothing fancy at all. Okay, we’ve got the repo set up, now let’s get the service setup.

Create the Azure Static Web App resource

You’ll need an Azure account of course and if you don’t have one, you can create an Azure account for free. Go ahead and do that and then come back here to make it easier to follow along. Once you have the account you’ll log in to the Azure portal and create a new resource using the Static Web App (Preview) resource type. You’ll see a simple form to fill out a few things like your resource group and a name for your app and the region.

Screenshot of Azure Portal configuration

The last thing there is where you’ll connect to your GitHub repo and make selections for what repo to use. It will launch you to authorize Azure Static Web Apps to make changes to your repo (for workflow and adding secrets):

Picture of GitHub permission prompt

Once authorized then more options show for the resource creation and just choose your org/repo/branch:

Picture of GitHub repo choices

Once you complete these selections, click Review+Create and the resource will create! The process will take a few minutes, but when complete you’ll have a resource with a few key bits of information:

Picture of finished Azure resource config

The URL of your app is auto-generated with probably a name that will make you chuckle a bit. Hey, it’s random, don’t try to make sense of it, just let the names like “icy cliff” inspire you. Additionally you’ll see the “Workflow file” YAML file and link. If you click it (go ahead and do that) it will take us over to your repo and the GitHub Actions workflow file that was created. We’ll take a look at the details next, but for now if you navigate to the Actions tab of your repo, you’ll see a fail. This is expected for us right now in our steps…more on that later.

Picture of workflows in Actions

In addition to the Actions workflow navigate to the settings tab of your repo and choose Secrets. You’ll see a new secret (with that random name) was added to your repo.

Picture of GitHub secrets

This is the API token needed to communicate with the service.

Why can’t you see the token itself and give the secret a different name? Great question. For now just know that you can’t. Maybe this will change, but this is the secret name you’ll have to use. It’s cool though, the only place it is used is in your workflow file. Speaking of that file, let’s take a look more in detail now!

Understanding and modifying the Action

So the initial workflow file was created and added to your workflow has all the defaults. Namely we’re going to focus on the “jobs” node of the workflow, which should start about line 12. The previous portions in the workflow define the triggers which you can modify if you’d like but they are intended to be a part of your overall CI/CD flow with the static site (automatic PR closure, etc.). Let’s look at the jobs as-is:

jobs:
  build_and_deploy_job:
    if: github.event_name == 'push' || (github.event_name == 'pull_request' && github.event.action != 'closed')
    runs-on: ubuntu-latest
    name: Build and Deploy Job
    steps:
    - uses: actions/[email protected]
    - name: Build And Deploy
      id: builddeploy
      uses: Azure/[email protected]
      with:
        azure_static_web_apps_api_token: ${{ secrets.AZURE_STATIC_WEB_APPS_API_TOKEN_ICY_CLIFF_XXXXXXXXX }}
        repo_token: ${{ secrets.GITHUB_TOKEN }} # Used for Github integrations (i.e. PR comments)
        action: 'upload'
        ###### Repository/Build Configurations - These values can be configured to match you app requirements. ######
        app_location: '/' # App source code path
        api_location: 'api' # Api source code path - optional
        app_artifact_location: '' # Built app content directory - optional
        ###### End of Repository/Build Configurations ######

Before we make changes, let’s just look. Oh see that parameter for api token? It’s using that secret that was added to your repo. GitHub Actions has built in a ‘secrets’ object that can reference those secrets and this is where that gets used. That is required for proper deployment. So there, that is where you can see the relationship to it being used!

This is great, but also was failing for our Blazor Wasm app. Why? Well because it’s trying to build it and doesn’t quite know how yet. That’s fine, we can help nudge it along! I’m going to make some changes here. First, change the checkout version to @v2 on Line 18. This is faster.

NOTE: I suspect this will change to be the default soon, but you can change it now to use v2

Now we need to get .NET SDK set up to build our Blazor app. So after the checkout step, let’s add another to first set up the .NET SDK we want to use. It will look like this, using the setup-dotnet action:

    - uses: actions/[email protected]
    
    - name: Setup .NET SDK
      uses: actions/[email protected]
      with:
        dotnet-version: 3.1.201

Now that we are setup, we need to build the Blazor app. So let’s add another step that explicitly builds the app and publish to a specific output location for easy reference in a later step!

    - uses: actions/[email protected]
    
    - name: Setup .NET SDK
      uses: actions/[email protected]
      with:
        dotnet-version: 3.1.201

    - name: Build App
      run: dotnet publish -c Release -o published

There, now we’ve got it building!

NOTE: I’m taking a bit of a shortcut in this tutorial and I’d recommend the actual best practice of Restore, Build, Test, Publish as separate steps. This allows you to more precisely see what is going on in your CI and clearly see what steps may fail, etc.

Our Blazor app is now build and prepared for static deployment in the location ‘published’ referenced in our ‘-o’ parameter during build. All the files we need start now at the root of that folder. A typical Blazor Wasm app published will have a web.config and a wwwroot at the published location.

Picture of Windows explorer folders

Let’s get back to the action defaults. Head back to the YAML file and look for the ‘app_location’ parameter in the action. We now want to change that to our published folder location, but specifically the wwwroot location as the root (as for now the web.config won’t be helpful). So you’d change it to look like this (a snippet of the YAML file)

    - uses: actions/[email protected]
    
    - name: Setup .NET SDK
      uses: actions/[email protected]
      with:
        dotnet-version: 3.1.201

    - name: Build App
      run: dotnet publish -c Release -o published

    - name: Build And Deploy
      id: builddeploy
      uses: Azure/[email protected]
      with:
        azure_static_web_apps_api_token: ${{ secrets.AZURE_STATIC_WEB_APPS_API_TOKEN_ICY_CLIFF_XXXXXXXXX }}
        repo_token: ${{ secrets.GITHUB_TOKEN }} # Used for Github integrations (i.e. PR comments)
        action: 'upload'
        ###### Repository/Build Configurations - These values can be configured to match you app requirements. ######
        app_location: 'published/wwwroot' # App source code path
        api_location: '' # Api source code path - optional
        app_artifact_location: 'published/wwwroot' # Built app content directory - optional
        ###### End of Repository/Build Configurations ######

This tells the Static Web App deployment steps to push our files from here. Go ahead and commit the workflow file back to your repository and the Action will trigger and you will see it complete:

Screenshot of completed workflow steps

We have now successfully deployed our Blazor Wasm app to the Static Web App Preview service! Now you’ll note that there is a lot of output in the Deploy step, including warnings about build warnings. For now this is okay as we are not relying on the service to build our app (yet). You’ll also see the note about Functions not being found (reminder we changed our parameter to not have that value). Let’s talk about that.

What about the Functions?

For now the service will automatically build a JavaScript app including serverless functions built using JavaScript in this one step. If you are a .NET developer you’ll most likely be building your functions in C# along with your Blazor front-end. Right now the service doesn’t automatically allow you to specify an API location in your project for C# function classes and automatically build them. Hopefully in the future we will see that be enabled. Until then you’ll have to deploy your functions app separately. You can do it in the same workflow though if it is a part of your same repo. You’ll just leverage the other Azure Functions GitHub Action to accomplish that. Maybe I should update my sample repo to also include that?

But wait, it is broken!

Well maybe you find out that the routing of URLs may not work all the time.  You’re right!  You need to supply a routes.json file located in your app’s wwwroot directory to provide the global rewrite rule so that URLs will always work.  The routes.json file should look like

{
  "routes": [
    {
      "route": "/*",
      "serve": "/index.html",
      "statusCode": 200
    }
  ]
}

and put in your source project’s wwwroot folder.  This will be picked up by the service and interpreted so routes work!

Considerations and Summary

So you’ve now seen it’s possible, but you should also know the constraints. I’ve already noted that you’ll need to deploy your Functions app separately and you have to build your Blazor app in a pre-step (which I think is a good thing personally), so you may be wondering why might you use this service. I’ll leave that answer to you as I think there are scenarios will it will be helpful and I do believe this is just a point in time for the preview and more frameworks hopefully will be supported. I know those of us on the .NET team are working with the service to better support Blazor Wasm, for example.

Another thing that Blazor build does for you is produce pre-compressed files for Brotli and Gzip compression delivered from the server. When you host Blazor Wasm using ASP.NET Core, we deliver these files to the client automatically (via middleware). When you host using Windows App Service you can supply a web.config to have rewrite rules that will solve this for you as well (you can in Linux as well). For the preview of the Static Web App service and Blazor Wasm, you won’t automatically get this, so your app size will be the default uncompressed sizes of the assemblies and static assets.

I hope that you can give the service a try with your apps regardless of if they are Blazor or not. I just wanted to demonstrate how you would get started using the preview making it work with your Blazor Wasm app. I’ve added this specific workflow to my Blazor Wasm Deployment Samples repository where you can see other forms as well on Azure to deploy the client app.

I hope this helps see what’s possible in preview today!

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Everyone!  As a part of my responsibilities on the Visual Studio team for .NET tools I try to spend the time using our products in various different ways, learning what pitfalls customers may face and ways to solve them.  I work a lot with Azure services and how to deploy apps and I’m a fan of GitHub Actions so I thought I’d share some of my latest experiments.  This post will outline the various ways as of this writing you can host Blazor WebAssembly (Wasm) applications.  We actually have some great documentation on this topic in the Standalone Deployment section of our docs but I wanted to take it a bit further and demonstrate the GitHub Actions deployment of those options to Azure using the Azure GitHub Actions.

Let’s get started!

If you don’t know what Blazor Wasm is then you should read a bit about What is Blazor on our docs.  Blazor Wasm enables you to write your web application front-end using C# with .NET running in the browser.  This is different than previous models that enabled you to write C# in the browser like Silverlight where a separate plug-in was required to enable this.  With modern web standards and browser, WebAssembly has emerged as a standard to enable compilation of high-level languages for web deployment via browsers.  Blazor enables you to use C# and create your web app from front-end to back-end using a single language and .NET.  It’s great.  When you create a Blazor Wasm project and publish the output you are essentially creating a static site with assets that can be deployed to various places as there is no hard server requirement (other than to be able to serve the content and mime types).  Let’s explore these options…

ASP.NET Core-hosted

For sure the simplest way to host Blazor Wasm would be to also use ASP.NET Core web app to serve it.  ASP.NET Core is cross-platform and can run pretty much anywhere.  If you are likely using C# for all your development, this is likely the scenario you’d be using anyway and you can deploy your web app, which would container your Blazor Wasm assets as well to the same location (Linux, Windows, containers).  When creating a Blazor Wasm site you can choose this option in Visual Studio by selecting these options:

Blazor Wasm creation in Visual Studio

or using the dotnet CLI using this method:

dotnet new blazorwasm --hosted -o YourProjectName

Both of these create a solution with a Blazor Wasm client app, ASP.NET Core Server app, and a shared (optional) library project for sharing code between the two (like models or things like that).  This is an awesome option and your deployment method would follow the same method of deploying the ASP.NET Core app you’d already be using.  I won’t focus on that here as it isn’t particularly unique.  One advantage of using this method is ASP.NET Core already has middleware to properly serve the pre-compressed Brotli/gzip formats of your Blazor Wasm assets from the server, reducing the payload across the wire.  You’ll see more of this in below options, but using ASP.NET Core does this automatically for you.  You can deploy your app to Azure App Service or really anywhere else easily.

Benefits:

  • You’re deploying a ‘solution’ of your full app in one place, using the same tech to host the front/back end code
  • ASP.NET Core enables a set of middleware for you for Blazor routing and compression

Be Aware:

  • Basically billing.  Know that you would most likely host in an App Service or non-serverless (consumption) model.  It’s not a negative, just an awareness.

Azure Storage

If you just have the Blazor Wasm site and are calling in to a set of web APIs, serverless functions, or whatever and you just want to host the Wasm app only then using Storage is an option.  I actually already wrote about this previously in this blog post Deploy a Blazor Wasm Site to Azure Storage Using GitHub Actions so I won’t repeat it here…go over there and read that detail.

Example GitHub Action Deployment to Azure Storage: azure-deploy-storage.yml

Benefits:

  • Consumption-based billing for storage.  You aren’t paying for ‘on all the time’ compute
  • Blob-storage managed (many different tools to see the content)

Be Aware:

  • Routing: errors will need to be routed to index.html as well and even though they will be ‘successful’ routes, it will still be an HTTP 404 response code.  This could be mitigated by adding Azure CDN in front of your storage and using more granular rewrite rules (but this is also an additional service)
  • Pre-compressed assets won’t be served as there is no middleware/server to automatically detect and serve these files.  Your app will be larger than it could be if serving the compressed brotli/gzip assets.

Azure App Service (Windows)

You can directly publish your Blazor Wasm client app to Azure App Service for Windows.  When you publish a Blazor Wasm app, we provide a little web.config in the published output (unless you supply your own) and this contains some rewrite information for routing to index.html.  Since App Service for Windows uses IIS when you publish this output this web.config is used and will help your app routing.  You can also publish from Visual Studio using this method as well:

Visual Studio publish dialog

or using GitHub Actions easily using the Azure Actions.  Without the ASP.NET Core host you will want to provide IIS with better hinting on the pre-compressed files as well.  This is documented in our Brotli and Gzip documentation section and a sample web.config is also provided in this sample repo.  This web.config in the root of your project (not in the wwwroot) will be used during publish instead of the pre-configured one we would provide if there was none.

Example GitHub Action Deployment to Azure App Service for Windows: azure-app-svc-windows-deploy.yml

Benefits:

  • Easy deployment and default routing configuration provided in published output
  • Managed PaaS
  • Publish easily from Actions or Visual Studio

Be Aware:

  • Really just understanding your billing choices for the App Service

Azure App Service (Linux w/Containers)

If you like containers, you can put your Blazor Wasm app in a container and deploy that where supported, including Azure App Service Containers!  This enables you to encapsulate a little bit more in your own container image and also control the configuration of the server a bit more.  For Linux, you’d be able to specify a specific OS image you want to host your app and even supply the configuration of that server.  This is nice because we need to do a bit of that for some routing rules for the Wasm app.  Here is an example of a Docker file that can be used to host a Blazor Wasm app:

FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env
WORKDIR /app

COPY . ./
WORKDIR /app/
RUN dotnet publish -c Release

FROM nginx:1.18.0 AS build
WORKDIR /src
RUN apt-get update && apt-get install -y git wget build-essential libssl-dev libpcre3-dev zlib1g-dev
RUN CONFARGS=$(nginx -V 2>&1 | sed -n -e 's/^.*arguments: //p') \
    git clone https://github.com/google/ngx_brotli.git && \
    cd ngx_brotli && git submodule update --init && cd .. && \
    wget -nv http://nginx.org/download/nginx-1.18.0.tar.gz -O - | tar -xz && \
    cd nginx-1.18.0 && \ 
    ./configure --with-compat $CONFARGS --add-dynamic-module=../ngx_brotli

WORKDIR nginx-1.18.0
RUN    make modules

FROM nginx:1.18.0 as final

COPY --from=build /src/nginx-1.18.0/objs/ngx_http_brotli_filter_module.so /usr/lib/nginx/modules/
COPY --from=build /src/nginx-1.18.0/objs/ngx_http_brotli_static_module.so /usr/lib/nginx/modules/

WORKDIR /var/www/web
COPY --from=build-env /app/bin/Release/netstandard2.1/publish/wwwroot .
COPY nginx.conf /etc/nginx/nginx.conf
EXPOSE 80 443

In this configuration we’re using an image to first build/publish our Blazor Wasm app, then using the nginx:1.18.0 image as our base and building the nginx_brotli compression modules we want to use (lines 8-19,23-24).  We want to supply some configuration information to the nginx server and we supply an nginx.conf file that looks like this:

load_module modules/ngx_http_brotli_filter_module.so;
load_module modules/ngx_http_brotli_static_module.so;
events { }
http {
    include mime.types;
    types {
        application/wasm wasm;
    }
    server {
        listen 80;
        index index.html;

        location / {
            root /var/www/web;
            try_files $uri $uri/ /index.html =404;
        }

        brotli_static on;
        brotli_types text/plain text/css application/javascript application/x-javascript text/xml application/xml application/xml+rss text/javascript image/x-icon image/vnd.microsoft.icon image/bmp image/svg+xml application/octet-stream application/wasm;
        gzip on;
        gzip_types      text/plain application/xml application/x-msdownload application/json application/wasm application/octet-stream;
        gzip_proxied    no-cache no-store private expired auth;
        gzip_min_length 1000;
        
    }
}

Now when we deploy the Docker image is composed, provided to Azure Container Registry and then deployed to App Service for us.  In the above example, the first two lines are loading the modules we build in the Docker image previously.

Example GitHub Action Deployment to Azure App Service using Linux Container: azure-app-svc-linux-container.yml

Benefits:

  • Containers are highly customizable, allowing you some portability and flexibility
  • Easy deployment from Actions and Visual Studio (you can use the same publish mechanism in VS)

Be Aware

  • Additional service here of using Azure Container Registry (or another registry to pull from)
  • Understanding your billing plan for App Service
  • Might need more configuration awareness to take advantage of pre-compressed assets (by default nginx requires an additional module for brotli and you’d have to rebuild it into nginx)
    • NOTE: The example repo has a sample configuration which adds brotli compression support for nginx

Azure App Service (Linux)

Similarly to App Service for Windows you could also just use App Service for Linux to deploy your Wasm app.  However there is a big known workaround you have to achieve right now in order to enable this method.  Primarily this is because there is no default configuration or ability to use the web.config like you can for Windows.  Because of this if you use the Visual Studio publish mechanism it will appear as if the publish fails.  Once completed and you navigate to your app you’d get a screen that looks like the default “Welcome to App Service” page if no content is there.  This is a bit of a false positive :-).  Your content/app DOES get published using this mechanism, but since we pus the publish folder the App Service Linux configuration doesn’t have the right rewrite defaults to navigate to index.html.  Because of this I’d recommend if Linux is your desired host, that you use containers to achieve this.  However you CAN do this using GitHub Actions as you manipulate the content to push.

Example GitHub Action Deployment to Azure App Service Linux: azure-app-svc-linux-deploy.yml

Benefits:

  • Managed PaaS

Be Aware:

  • Cannot publish ideally from Visual Studio
  • No pre-compressed assets will be served
  • Understand your billing plan for App Service

Summary

Just like you have options with SPA frameworks or other static sites, for a Blazor Wasm client you have similar options as well.  The unique aspects of pre-compressed assets provide some additional config you should be aware of if you aren’t using ASP.NET Core hosted solutions, but with a small bit of effort you can get it working fine. 

All of the samples I have listed here are provided in this repository: timheuer/blazor-deploy-samples and would love to see any issues you may find.  I hope this helps summarize the documentation we have on configuring options in Azure to support Blazor Wasm.  What other tips might you have?

Stay tuned for more!

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I’ve been spending a lot of time looking at the GitHub Actions experience for .NET developers.  Right now I’m still using Azure Pipelines for my project, Alexa.NET, in building, testing, and deploying to NuGet.  As the tools and process for using DevOps tools for CI/CD have so vastly improved over the years, I’ve become a huge advocate for this being the means for your build/deploy steps…YES, even as a single developer or a smaller team.  It simply really helps you get to a purer sense of preserving the ability for your code to live on, for others to accurately build it, and for you to have peace of mind that your code works as intended.  I’m just such a huge fan now.  That said, I still think there is a place for ‘right-click publish’ activities in inner-loop development.  In fact, I use it regularly for a few internal apps I’ve written.  For simple solutions that method works well, but I certainly don’t think I can right-click-publish a full solution to a Kubernetes environment though.  I’m currently researching new tooling ways to help those ‘publish to CI/CD’ from Visual Studio (would love your opinions here) so I’ve been spending a lot more time in GitHub Actions.  I decided to look at publishing a Blazor app to Azure Storage as a static site…here’s what I did.

Setting up the Storage endpoint

The first thing you need is an Azure Storage account.  Don’t have an Azure account, no worries you can get a Free Azure account easily which includes up to 5GB of Azure Blob Storage free for the first 12 months.  Worried about pricing afterwards?  Well check out the storage pricing calculator and I’m sure you’ll see that even at 1TB storage it is cost-effective means of storage.  But any rate, you need a storage account and here are the configuration you need.

First, you may already have one.  As a developer do you create your infrastructure resources or are these provisioned for you by infra/devops roles in your company (leave comments)?  Earlier this year at Build we enabled static website hosting in Azure Storage.  You first create a Storage resource (ensuring you choose v2 which is the default, but that is the version that enables this feature).  After you create your resource scroll on the left and you’ll see ‘Static website' section.  Here’s what the configuration looks like and let me explain a few areas here:

Screenshot of the Static website configuration
All of this configuration is under the Static website area.  First you obviously need to enable it…that’s just toggling the enabled/disabled capability.  Enabling this now gets you two things: 2 endpoints (basically the URI to the website) and a specific blob contianer named $web where your static content needs to live.  The endpoints default map to this blob container without having to add a container name to the root URI.  Remember the resource group you’ve given to your storage instance here, you will need that later.

NOTE: You can later add CDN/custom domain to these endpoints, but I’m not covering those here.

The second thing you need is to set a default document and error page.  The default document for your SPA is your root entry point, and for most frameworks I’ve seen this is indeed index.html.  For Blazor WebAssembly (WASM) apps, this is also the default if you are using the template.  So you set the default document as ‘index.html’ and move on.  The error document path is another interesting one…you need to set this for SPA apps because right now the static website capability of Azure Storage does not account for custom routing rules.  What this means is that storage will throw an HTTP 404 error message when you go to something like /somepage where it actually doesn’t exist but your SPA framework knows how to handle it.  Until custom routing works on Azure Storage your error document becomes your route entry point.  So for this set the error document path to also be index.html for Blazor WASM.

NOTE: Yes this isn’t ideal for routing.  On top of that it still does show an HTTP 404 actual network message even though your route is being handled.  Azure Storage team has heard this request…working on advocating for y’all.

That’s it.  Now you have a storage endpoint with a blob container that you can begin putting your content in and browse to using your endpoint URI provided from the portal.  For a simple tool to navigate your storage, I’ve been using Azure Storage Explorer and it is intuitive to me and works well to quickly navigate your storage account and containers (and supports multi-account!). 

Setting up your Azure Service Principal credentials

The next thing you will need is a service principal credential.  This will be used to authenticate with your Azure account to be able to use DevOps tools to work on your behalf in your account.  It’s a simple process if you have a standard account.  I say this only because I know there might be some configurations for environments where you yourself don’t have access to create service principals and may need someone to create one on your behalf, or also there might be credentials you can already use.  Either way here is the process I used.

I used the Azure CLI so if you don’t have that installed go ahead and grab that and install it.  This should now be in your PATH environment and using your favorite terminal you should be able to start executing commands.  To start out, login to the CLI using `az login` – this will launch a browser for you to authenticate via your account and then issue the token in your environment so that for the remainder of your session you’ll be authenticated.  After logging in successfully running `az account show` will emit what subscription you are using and you’ll need the subscription ID later so grab that and put it somewhere on your scratch notepad for later command usage.

NOTE: If you have more than one subscription and have not set a default subscription you should set that using the `az account set` command.

Now you can use the CLI to create a new service principal.  To do that issue this command:

az ad sp create-for-rbac --name "myApp" --role contributor \
                            --scopes /subscriptions/{subscription-id}/resourceGroups/{resource-group} \
                            --sdk-auth

Note on line 2 here that you need to replace {subscription-id} with your own actual subscription id (the GUID) and {resource-group} with the resource group name where your storage account is located.  On line 1 the “myApp” can be anything but I recommend making it meaningful as this is basically the account name of the principal.  The output of this command is your service principal.  The full JSON output.  Save this off in a place for now as we’ll need that later to configure GitHub Actions properly.  Great now to move on to the app!

Create your Blazor WASM app

I assume since you may be reading this far you aren’t new to Blazor and probably already have the tools.  As of this writing, Blazor WASM is still in preview so you have to install the templates separately to acquire them to show up in `dotnet new` and in Visual Studio File…New Project.  To do that from a terminal run:

dotnet new -i Microsoft.AspNetCore.Blazor.Templates::3.1.0-preview4.19579.2

Then you will be able to create a new project.  I’m showing Visual Studio here and this is the WASM template:

Screenshot of Blazor new project dialog

In the dialog here you will see Blazor WebAssembly App and that’s what you will use.  Now you have a choice to have it ASP.NET Core hosted using that checkbox, which if you were going to do other things in ASP.NET maybe that’s what you want.  For the purposes of this article we are talking about just having the WASM app and having a place to host it that isn’t a web server with other content…just hosting static content and using storage to do so…so we aren’t checking that box.  The result will be a Blazor WASM app with no host.  Now let’s add that to GitHub.  If you are using Visual Studio 16.4+ you’ll be able to take advantage of an improved flow for pushing to GitHub.  Once you have your project, in the lower right click ‘Add to Source Control’ choosing Git and then you’ll see the panel to choose GitHub and create/push a repo right away.  You don’t have to go to GitHub site first and clone later…all in one step:

Animation of Visual Studio GitHub flow

Great!  Now we have our WASM project and we’ve created and pushed the current bits to a new GitHub repository.  Now to create the workflow.

Setup the GitHub Action Workflow

Now we’ve got an Azure Storage blob container, a service principal, a Blazor WASM project, and a GitHub repository…all set to configure the CI/CD flow now.  First let’s put that service principal as a secret in our repository.  In the settings of your repository navigate to the Secrets section and add a secret named AZURE_CREDENTIALS.  The content of this is the full content of your service principal (the JSON blob) that we generated earlier:

Screenshot of GitHub Secrets configuration

This saves the secret for us to use in the workflow and reference as a variable.  You can add more secrets here if you’d like if you wanted to add your resource storage account name as well (probably a good idea).  Secrets are isolated to the original repository so no forks get the secrets at all.  Now that we have these let’s create the workflow file.

Today, Visual Studio isn’t too helpful in authoring the YAML files (would love your feedback here too!) but a GitHub Action is just a YAML file in a specific location in your repository: .github/workflows/azure-storage-deploy.yaml.  The file name can be anything but putting it in this folder structure is what is required.  You can start in the GitHub repo itself using the Actions tab and through the online editor get some level of completion assistance to help you navigate the YAML editing.  Go to the Actions tab in your repository and create a new workflow.  You’ll be offered a starter workflow based on what GitHub thinks your project is like.  As of this writing it thinks Blazor apps are Jekyll workflows so you’ll need to expand and either find the .NET Core one or just start from a blank workflow yourself.

Screenshot of GitHub Actions config

Four my workflow I want to build, publish and deploy my app.  I’ve separated it into a build and deploy jobs.  You can read all about the various aspects of GitHub Actions in their docs with regard to jobs and other syntax as I won’t try to expound upon that in this article.  Here is my full YAML for the entire workflow with some key areas highlighted:

name: .NET Core Build and Deploy

on: [push]

env:
  AZURE_RESOURCE_GROUP: blazor-deployment-samples
  BLOB_STORAGE_ACCOUNT_NAME: timheuerblazorwasm

jobs:
  build:
    name: Build
    runs-on: ubuntu-latest
    steps:
    - uses: actions/[email protected]
    - name: Setup .NET Core
      uses: actions/[email protected]
      with:
        dotnet-version: 3.1.100

    - name: Build with dotnet
      run: dotnet build --configuration Release
    
    - name: Publish with dotnet
      run: dotnet publish --configuration Release 
    
    - name: Publish artifacts
      uses: actions/[email protected]
      with:
        name: webapp
        path: bin/Release/netstandard2.1/publish/BlazorApp27/dist

  deploy:
    needs: build
    name: Deploy
    runs-on: ubuntu-latest
    steps:

    # Download artifacts
    - name: Download artifacts
      uses: actions/[email protected]
      with:
        name: webapp

    # Authentication
    - name: Authenticate with Azure
      uses: azure/[email protected]
      with:
        creds: ${{ secrets.AZURE_CREDENTIALS  }}

    # Deploy to storage using CLI
    - name: Deploy to storage using CLI
      uses: azure/[email protected]
      with:
        azcliversion: latest
        inlineScript: | 
          # show azure account being used
          az account show
          # az storage account upload
          az storage blob upload-batch --account-name ${{ env.BLOB_STORAGE_ACCOUNT_NAME }} -s webapp -d \$web
          # az set content type of wasm file until this is fixed by default from Azure Storage
          az storage blob update --account-name ${{ env.BLOB_STORAGE_ACCOUNT_NAME }} -c \$web -n _framework/wasm/mono.wasm --content-type application/wasm

So a few things going on here, let’s talk about them.

  • Lines 5-7: these are ‘local’ environment variables I set up.  The storage account name is NOT the blob container name but the actual storage account name.  This ideally probably should be a Secret as mentioned above.  Environment variables can be set here and then placeholders reference them later.
  • Starting at line 9 is where the ‘build’ portion is here.  We checkout the code, acquire the SDK and run the build and publish commands.  On line 26-30 is a step where we put the publish output to a specific artifact location for later retrieval of steps.  This is good practice.
  • Lines 40-42 is where we are now in the ‘deploy’ step of our CD and we retrieve those artifacts we previously pushed and we set them as a name ‘webapp’ that the later will use in deployment
  • Line 45 is where we are going to first authenticate to Azure using our service principal retrieved from the Secrets.  The ‘secrets’ object is not something you have to define and is part of the workflow so you just add the property you want to retrieve
  • Line 51 is where we start the deployment to Azure using the CLI commands and our param ‘webapp’ as the source.  This is the CLI command for uploading batch to storage as described in the docs for `az storage blob upload-batch`
  • Line 61 is an additional step that we need for .wasm files.  I believe this to be a bug because there is logic in the CLI to correctly map the content-type but for some reason it is not working…so for now you need to set the content-type for .wasm to `application/wasm` or the Blazor app will not work

This is made possible through a series of actions: checkout, dotnetcore, azure…all brining their functionality we can draw on and configure.  There are a bunch of Azure GitHub Actions we just released for specific tasks like deploying to App Service and such.  These don’t require CLI commands but rather just provide parameters to configure.  Because there is no Storage specific Action as of now, we can use the default CLI action to script what we want.  It is an enabler in lieu of a more strongly-typed action.  Now that we have this workflow YAML file complete we can commit and push to the repository.  In doing that we now have a CI/CD action that will trigger on any push (because that’s how we configured it).  We can see this action happening in my sample repo and you can see since we separate it in two jobs it will show them separately:

Screenshot of action deployment log

Summary

So now we have it complete end-to-end.  And subsequent check-in will trigger the workflow and deploy the bits to my storage account and I can now use my Azure Storage account as a host for my static website built on Blazor WASM.  This full YAML sample flow is available on my repo for this and you can examine it in more detail.

I would love to know how y’all are coming along using GitHub Actions with your .NET projects.  Please comment below!