Scott Hanselman

I've recently returned from a month in South Africa and I was looking to unwind while the jetlagged kids sleep. I noticed that .NET Core 2.2 Preview 3 came out while I wasn't paying attention. My podcast site runs on .NET Core 2.2 Preview 2 so I thought it'd be interesting to update the site. That means I'd need to install the new SDK, update the project references, ensure it builds in Azure DevOps's CI/CD Pipeline, AND deploys and runs in Azure.

Let's see how it goes. I'm a little out of it but I'm writing this blog post AS I DO THE WORK so you'll see my train of thought with no editing.

Ok, what version of .NET Core does this machine have?

C:\Users\scott> dotnet --version
2.2.100-preview2-009404
C:\Users\scott> dotnet tool update --global dotnet-outdated
Tool 'dotnet-outdated' was successfully updated from version '2.0.0' to version '2.1.0'.

Looks like I'm on Preview 2 as I guessed. I'll take a moment and upgrade one Global Tool I love - dotnet-outdated - in case it's been updated since I've been out. Looks like it has a minor update. Dotnet Outdated is a great utility for checking references and you should absolutely be using it or another tool like NuKeeper or Dependabot.

I'll head over to https://www.microsoft.com/net/download/dotnet-core/2.2 and get .NET Core 2.2 Preview 3. I'm building on Windows but I may want to update my Linux (WSL) install and Docker images later.

All right, installed. Check it with dotnet --version to confirm it's correct:

C:\Users\scott> dotnet --version
2.2.100-preview3-009430

Let's try to build my podcast website. Note that it consists of two projects, the main website on ASP.NET Core, and Unit Tests with XUnit and Selenium.

D:\github\hanselminutes-core [main ≡]> dotnet build
Microsoft (R) Build Engine version 15.9.8-preview+g0a5001fc4d for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  Restoring packages for D:\github\hanselminutes-core\hanselminutes.core.tests\hanselminutes.core.tests.csproj...
  Restore completed in 80.05 ms for D:\github\hanselminutes-core\hanselminutes.core.tests\hanselminutes.core.tests.csproj.
  Restore completed in 25.4 ms for D:\github\hanselminutes-core\hanselminutes.core\hanselminutes-core.csproj.
D:\github\hanselminutes-core\hanselminutes.core.tests\hanselminutes.core.tests.csproj : error NU1605: Detected package downgrade: Microsoft.AspNetCore.App from 2.2.0-preview3-35497 to 2.2.0-preview2-35157. Reference the package directly from the project to select a different version.  [D:\github\hanselminutes-core\hanselminutes-core.sln]

The dotnet build fails, which make sense, because it's saying hey, you're asking for 2.2 Preview 2 but I've got Preview 3 all ready for you!

Detected package downgrade: Microsoft.AspNetCore.App from 2.2.0-preview3-35497 to 2.2.0-preview2-35157

Let's see what "dotnet outdated" says about this!

Cool! I love these dependency tools and the community around them. You can see that it's noticed the Preview 2 -> Preview 3 opportunity, as well as a few other smaller minor or patch version bumps.

I can run dotnet outdated -u to automatically update the references, but I'll want to treat the "reference" of "Microsoft.AspNetCore.App" a little differently and use implicit versioning. You don't want to include a specific version - as I did - for this package.

Per the docs for .NET Core 2.1 and up:

Remove the "Version" attribute on the package reference to Microsoft.AspNetCore.App. Projects which use <Project Sdk="Microsoft.NET.Sdk.Web"> do not need to set the version. The version will be implied by the target framework and selected to best match the way ASP.NET Core 2.1 works. (See below for more information.)

Doing this also fixes the build because it picks up the latest 2.2 SDK automatically! Now I'll run my Unit Tests (with code coverage) and see how it works. Cool all tests pass (including Selenium).

It builds locally, will it build in Azure DevOps when I check it in to GitHub?

I added a .NET Core SDK installer step when I set up my Azure Dev Ops Pipeline. This is where I'm explicitly installing a Preview version of the .NET Core SDK.

While I'm in here I noticed the Azure DevOps pipeline was using NuGet 4.4.1. I run "nuget update -self" on my local machine and got 4.7.1, so I updated that version as well to make the CI/CD pipeline reflect my own machine.

Now I'll git add, git commit (using verified/signed GitHub commits with my PGP Key and Yubikey):

D:\github\hanselminutes-core [main ≡ +0 ~2 -0 !]> git add .
D:\github\hanselminutes-core [main ≡ +0 ~2 -0 ~]> git commit -m "bump to 2.2 Preview 3"
[main 7a84bc7] bump to 2.2 Preview 3
 2 files changed, 16 insertions(+), 13 deletions(-)

Add in a Git Push...and I can see the build start in Azure DevOps:

Cool. While that's building, I'll make sure my existing Azure App Service (website) installation is ready to receive the deployment (assuming the build succeeds). Since I'm using an ASP.NET Core Preview build I'll want to make sure I have the Preview Site Extension installed, per the docs.

If I visit the Site Extensions menu item in the Azure Portal I can see I've got .NET Core 2.2 Preview 2, but there's an update available, as expected.

I'll click this extension and then click Update. This extension's job is to make sure the App Service gets Preview versions of the .NET Core SDK. Only released (GA - general availability) SDKs are installed by default.

OK, .NET Core 2.2 is all updated in Azure, so I'll confirm that it's deployed as well in Azure DevOps. Yes, I'm deploying into Production without a net. Seriously, though, if there is an issue I'll just rollback. If I was deeply serious about downtime I'd be doing all this in Staging.

Successful local test, successful CI/SD build and test, successful deployment, and the site is back up now running on ASP.NET Core 2.2 Preview 3. It took about 45 min to do the work while simultaneously taking these screenshots and writing this blog post during the slow parts.

Good night everyone!

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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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I saw this Kickstarter today - Meadow: Full-stack .NET Standard IoT platform. It says that "It combines the best of all worlds; it has the power of RaspberryPi, the computing factor of an Arduino, and the manageability of a mobile app. And best part? It runs full .NET Standard on real IoT hardware."

NOTE: I don't have any relationship with the company/people behind this Kickstarter, but it seems interesting so I'm sharing it with you. As with all Kickstarters, it's not a pre-order, it's an investment that may not pan out, so always be prepared to lose your investment. I lost mine with the .NET "Agent" SmartWatch even though all signs pointed to success.

I've done IoT work on Raspberry Pis which is much easier lately with the emerging community support for ARM32, Raspberry Pis, and cool stuff happening on Windows 10 IoT. I've written on how easy it is to get running on Raspberry Pi. I was even able to get my own podcast website running on Raspberry Pi and in Docker.

This Meadow Kickstarter says it's running on the Mono Runtime and will support the .NET Standard 2.0 API. That means that you likely already know how to program to it. Most libraries on NuGet are .NET Standard compliant so a ton of open source software should "Just Work" on any solution that supports .NET Standard.

One thing that seems interesting about Meadow is this sentence: "The power of Raspberry Pi in the computing factor of an Arduino, and the manageability of a mobile app."

Raspberry Pis are full-on computers. Ardunios are small little (mostly) single-tasked devices. Microcomputer vs Microcontroller. It's overkill to have Ubuntu on a computer just to turn on a device. You usually want IoT devices to have as small a surface area as possible.

Meadow says "Meadow has been designed to run on a variety of microcontrollers, and our first board is based on STMicroelectronics' flagship STM32F7 MCU. The Meadow F7 Micro board is an embeddable module that's based on Adafruit Feather form factor." Remember, we are talking megs not gigs here. "We've paired the STM32F7 with 32MB of flash storage and 16MB of RAM, so you can run pretty much anything you can think of building." This is just a 216MHz ARM board.

Be sure to scroll all the way down to the bottom of the page as they outline risks as well as what's left to be done.

What do you think? While you are at it, check out (total coincidence) our sponsor this week is Intel IoT! They have some great developer kits.

Sponsor: Reduce time to market and simplify IOT development using developer kits built on Intel Atom®, Intel® Core™ and Intel® Xeon® processors and tools such as Intel® System Studio and Arduino Create*

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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I can run .NET Core on Windows, Mac, or a dozen Linuxes. On my Ubuntu installation I can check what version I have installed and where it is like this:

$ dotnet --version
2.1.403
$ which dotnet
/usr/bin/dotnet

If we interrogate that dotnet file we see it's a link to elsewhere:

$ ls -alogF /usr/bin/dotnet
lrwxrwxrwx 1 22 Sep 19 03:10 /usr/bin/dotnet -> ../share/dotnet/dotnet*

If we head over there we see similar stuff as we do on Windows.

Basically c:\program files\dotnet is the same as /share/dotnet.

$ cd ../share/dotnet
$ ll
total 136
drwxr-xr-x 1 root root   4096 Oct  5 19:47 ./
drwxr-xr-x 1 root root   4096 Aug  1 17:44 ../
drwxr-xr-x 1 root root   4096 Feb 13  2018 additionalDeps/
-rwxr-xr-x 1 root root 105704 Sep 19 03:10 dotnet*
drwxr-xr-x 1 root root   4096 Feb 13  2018 host/
-rw-r--r-- 1 root root   1083 Sep 19 03:10 LICENSE.txt
drwxr-xr-x 1 root root   4096 Oct  5 19:48 sdk/
drwxr-xr-x 1 root root   4096 Aug  1 18:07 shared/
drwxr-xr-x 1 root root   4096 Feb 13  2018 store/
-rw-r--r-- 1 root root  27700 Sep 19 03:10 ThirdPartyNotices.txt
$ ls sdk
2.1.4  2.1.403  NuGetFallbackFolder
$ ls shared
Microsoft.AspNetCore.All  Microsoft.AspNetCore.App  Microsoft.NETCore.App
$ ls shared/Microsoft.NETCore.App/
2.0.5  2.1.5

Looking in directories works to figure out what SDKs and Runtime versions are installed, but the best way is to use the dotnet cli itself like this. 

$ dotnet --list-sdks
2.1.4 [/usr/share/dotnet/sdk]
2.1.403 [/usr/share/dotnet/sdk]
$ dotnet --list-runtimes
Microsoft.AspNetCore.All 2.1.5 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.5 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.5 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.5 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

There's great instructions on how to set up .NET Core on your Linux machines via Package Manager here.

Note that these installs of the .NET Core SDK are installed in /usr/share. I can use the dotnet-install.sh to do non-admin installs in my own user directory.

In order to gain more control and do things more manually, you can use this shell script here: https://dot.net/v1/dotnet-install.sh and its documentation is here at docs. For Windows there is also a PowerShell version https://dot.net/v1/dotnet-install.ps1

The main usefulness of these scripts is in automation scenarios and non-admin installations. There are two scripts: One is a PowerShell script that works on Windows. The other script is a bash script that works on Linux/macOS. Both scripts have the same behavior. The bash script also reads PowerShell switches, so you can use PowerShell switches with the script on Linux/macOS systems.

For example, I can see all the current .NET Core 2.1 versions at https://www.microsoft.com/net/download/dotnet-core/2.1 and 2.2 at https://www.microsoft.com/net/download/dotnet-core/2.2 - the URL format is regular. I can see from that page that at the time of this blog post, v2.1.5 is both Current (most recent stable) and also LTS (Long Term Support).

I'll grab the install script and chmod +x it. Running it with no options will get me the latest LTS release.

$ wget https://dot.net/v1/dotnet-install.sh
--2018-10-31 15:41:08--  https://dot.net/v1/dotnet-install.sh
Resolving dot.net (dot.net)... 104.214.64.238
Connecting to dot.net (dot.net)|104.214.64.238|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 30602 (30K) [application/x-sh]
Saving to: ‘dotnet-install.sh’

I like the "-DryRun" option because it will tell you what WILL happen without doing it.

$ ./dotnet-install.sh -DryRun
dotnet-install: Payload URL: https://dotnetcli.azureedge.net/dotnet/Sdk/2.1.403/dotnet-sdk-2.1.403-linux-x64.tar.gz
dotnet-install: Legacy payload URL: https://dotnetcli.azureedge.net/dotnet/Sdk/2.1.403/dotnet-dev-ubuntu.16.04-x64.2.1.403.tar.gz
dotnet-install: Repeatable invocation: ./dotnet-install.sh --version 2.1.403 --channel LTS --install-dir <auto>

If I use the dotnet-install script can have multiple copies of the .NET Core SDK installed in my user folder at ~/.dotnet. It all depends on your PATH. Note this as I use ~/.dotnet for my .NET Core install location and run dotnet --list-sdks. Make sure you know what your PATH is and that you're getting the .NET Core you expect for your user.

$ which dotnet
/usr/bin/dotnet
$ export PATH=/home/scott/.dotnet:$PATH
$ which dotnet
/home/scott/.dotnet/dotnet
$ dotnet --list-sdks
2.1.402 [/home/scott/.dotnet/sdk]

Now I will add a few more .NET Core SDKs side-by-side with the dotnet-install.sh script. Remember again, these aren't .NET's installed with apt-get which would be system level and by run with sudo. These are user profile installed versions.

There's really no reason to do side by side at THIS level of granularity, but it makes the point.

$ dotnet --list-sdks
2.1.302 [/home/scott/.dotnet/sdk]
2.1.400 [/home/scott/.dotnet/sdk]
2.1.401 [/home/scott/.dotnet/sdk]
2.1.402 [/home/scott/.dotnet/sdk]
2.1.403 [/home/scott/.dotnet/sdk]

When you're doing your development, you can use "dotnet new globaljson" and have each path/project request a specific SDK version.

$ dotnet new globaljson
The template "global.json file" was created successfully.
$ cat global.json
{
  "sdk": {
    "version": "2.1.403"
  }
}

Hope this helps!

Sponsor: Reduce time to market and simplify IOT development using developer kits built on Intel Atom®, Intel® Core™ and Intel® Xeon® processors and tools such as Intel® System Studio and Arduino Create*

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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I noticed that last week .NET Core 2.2 Preview 3 was released:

• .NET Core 2.2 Preview 3
• ASP.NET Core 2.2 Preview 3
• Entity Framework 2.2 Preview 3

You can download and get started with .NET Core 2.2, on Windows, macOS, and Linux:

• .NET Core 2.2 Preview 3 SDK (includes the runtime)
• .NET Core 2.2 Preview 3 Runtime

Docker images are available at microsoft/dotnet for .NET Core and ASP.NET Core.

.NET Core 2.2 Preview 3 can be used with Visual Studio 15.9 Preview 3 (or later), Visual Studio for Mac and Visual Studio Code.

The feature I am most stoked about in ASP.NET 2.2 is a subtle one but I remember implementing it manually many times over the last 10 years. I'm happy to see it nicely integrated into ASP.NET Core's MVC and Razor Pages patterns.

ASP.NET Core 2.2 introduces the concept of Parameter Transformers to routing. Remember there isn't a directly relationship between what's in the URL/Address bar and what's on disk. The routing subsystem handles URLs coming in from the client and routes them to Controllers, but it also generates URLs (strings) when given an Controller and Action.

So if I'm using Razor Pages and I have a file Pages/FancyPants.cshtml I can get to it by default at /FancyPants. I can also "ask" for the URL when I'm creating anchors/links in my Razor Page:

<a class="nav-link text-dark" asp-area="" asp-page="/fancypants">Fancy Pants</a>

Here I'm asking for the page. That asp-page attribute points to a logical page, not a physical file.

We can make an IOutboundParameterTransformer that changes URLs to a format (for example) like a WordPress standard slug in the two-words format.

public class SlugifyParameterTransformer : IOutboundParameterTransformer
{
    public string TransformOutbound(object value)
    {
        if (value == null) { return null; }

        // Slugify value
        return Regex.Replace(value.ToString(), "([a-z])([A-Z])", "$1-$2").ToLower();
    }
}

Then you let the ASP.NET Pipeline know about this transformer, either in Razor Pages...

services.AddMvc()
            .SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
            .AddRazorPagesOptions(options =>
{
    options.Conventions.Add(
        new PageRouteTransformerConvention(
            new SlugifyParameterTransformer()));
});

or in ASP.NET MVC:

services.AddMvc(options =>
{
    options.Conventions.Add(new RouteTokenTransformerConvention(
                                 new SlugifyParameterTransformer()));
});

Now when I run my application, I get my routing both coming in (from the client web browser) and going out (generated via Razor pages. Here I'm hovering over the "Fancy Pants" link at the top of the page. Notice that it's generated /fancy-pants as the URL.

So that same code from above that generates anchor tags <a href= gives me the expected new style of URL, and I only need to change it in one location.

There is also a new service called LinkGenerator that's a singleton you can call outside the context of an HTTP call (without an HttpContext) in order to generate a URL string.

return _linkGenerator.GetPathByAction(
     httpContext,
     controller: "Home",
     action: "Index",
     values: new { id=42 });

This can be useful if you are generating URLs outside of Razor or in some Middleware. There's a lot more little subtle improvements in ASP.NET Core 2.2, but this was the one that I will find the most useful in the near term.

Sponsor: Check out the latest JetBrains Rider with built-in spell checking, enhanced debugger, Docker support, full C# 7.3 support, publishing to IIS and more advanced Unity support.

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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I've been exploring automated dependency tracking lately. I usually use my podcast's ASP.NET Core website that I host on Github as a guinea pig. I tried Nukeeper and the dotnet outdated global tool - both of which are fantastic and worth exploring.

This week I'm trying Dependbot. I have no relationship with this company. Public repos and personal account repos are free and their pricing is very clear and organization accounts start at just $15 with a free trial.

I'm really impressed with how clever Dependabot is. It's almost like a person in its behavior. Yes, I realize that's kind of the point, but it's no less surprising to see. A well-written bot is a joy to behold.

For example, here is a PR (Pull Request) where Dependbot says "Bumps Microsoft.ApplicationInsights.AspNetCore from 2.5.0-beta1 to 2.5.0-beta2."

Basic stuff, right? But that's not all.

It not only does the basics where it noticed that a version bump occurred in a NuGet package, but it also copied the release notes from that NuGet package's release on GitHub! It included links to what was fixed between versions, links to the change logs, AND a complete linked commit list. I mean, that's just lovely.

A few days later, Dependabot went and closed the PR because the dependancy had updated (I was slow) then it commented telling me this PR was superseded by another.

Dependabot, like any good bot, also includes commands you can send to it via "Chats" in GitHub PR comments. You can tell it to use specific labels, control milestones. You can also control behavior in the Dependabot Dashboard and have it automerge things like minor versions, or just lock things down to security-only updates.

All in all, it's a very smart bot that supports basically all the languages. .NET support is in Beta, but I haven't had any issues with it. You should definitely check it out. And let me tell you, once you've got everything automated you'll wonder how you ever managed before.

Sponsor: Check out the latest JetBrains Rider with built-in spell checking, enhanced debugger, Docker support, full C# 7.3 support, publishing to IIS and more advanced Unity support.

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

About   Newsletter

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