Scott Hanselman

The Squishy Side of Open Source

February 21, '18 Comments [8] Posted in Open Source
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The Squishy Side of Open SourceA few months back my friend Keeley Hammond and I did a workshop for Women Who Code Portland called The Squishy Side of Open Source. We'd done a number of workshops before on how to use Git and the Command Line, and I've done a documentary film with Rob Conery called Get Involved In Tech: The Social Developer (watch it free!) but Keeley and I wanted to really dive into the interpersonal "soft" or squishy parts. We think that we all need to work to bring kindness back into open source.

Contributing to open source for the first time can be scary and a little overwhelming. In addition to the technical skills required, the social dynamics of contributing to a library and participating in a code review can seem strange.

That means how people talk to each other, what to do when pull requests go south, when issues heat up due to misunderstandings,

Keeley has published the deck up on SpeakerDeck. In this workshop, we talked about the work and details that go into maintaining an open source community, tell real stories from his experiences and go over what to expect when contributing to open source and how to navigate it.

Key Takeaways:

  • Understanding the work that open source maintainers do, and how to show respect for them.
  • Understanding Codes of Conduct and Style Guides for OSS repos and how to abide by them.
  • Tips for communicating clearly, and dealing with uncomfortable or hostile communication.

Good communication is a key part of contributing to open source.

  • Give context.
  • Do your homework beforehand. It’s OK not to know things, but before asking for help, check a project’s README, documentation, issues (open or closed) and search the internet for an answer.
  • Keep requests short and direct. Many projects have more incoming requests than people available to help. Be concise.
  • Keep all communication public.
  • It’s okay to ask questions (but be patient!). Show them the same patience that you’d want them to show to you.
Keep it classy. Context gets lost across languages, cultures, geographies, and time zones. Assume good intentions in these conversations.

Where to start?

What are some good resources you've found for understanding the squishy side of open source?

Sponsor: Get the latest JetBrains Rider for debugging third-party .NET code, Smart Step Into, more debugger improvements, C# Interactive, new project wizard, and formatting code in columns.

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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How to set up Kubernetes on Windows 10 with Docker for Windows and run ASP.NET Core

January 30, '18 Comments [17] Posted in DotNetCore | Kubernetes | Open Source
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Docker for Windows is really coming along nicely. They have both a Stable and Edge channel and the Edge (beta, experimental) one just included a lovely new feature - Kubernetes support. Per their docs, Kubernetes is only available in Docker for Windows 18.02 CE Edge. They set most everything up nicely and put Kubectl into your path and setup a context. If you use kubectl for other things - like your own Raspberry Pi Kubernetes Cluster, then you'll need to be aware of switching contexts. Same thing applies if you have one in the cloud, like the Kubernetes Cluster I made in Azure AKS.

Got Docker for Windows? If you have not yet installed Docker for Windows, see Install Docker for Windows for an explanation of stable and edge channels, system requirements, and download/install information.

It's easy to get started, just click "Enable Kubernetes" and Docker for Windows will download and start the images you need. I clicked "show system containers" because I like to see what's hidden from me, but you decide for yourself. Do be aware - there's a TON.

Enabling Kubernetes in Docker for Windows

By default, you won't get the Kubernetes Dashboard - of which I'm a fan - so you may want to install that. If you follow the default instructions (and you're a noob like me) then you'll likely end up with a Dashboard that is pretty locked down. It can be somewhat frustrating to get access to your own development dashboard, so I use the alternative (read: totally insecure) dashboard, like this:

C:\> kubectl apply -f

I also like charts and graphs so I added these as well:

C:\> kubectl create -f
C:\> kubectl create -f
C:\> kubectl create -f

I can access the dashboard by default by running "kubectl proxy" then visiting this http://localhost:8001/ui and I'll get redirected to the dashboard:

Kuberenetes Dashboard

Now I can run through all the cool Kubernetes tutorials like the Guestbook Kubernetes Sample Application from the convenience of my Windows 10 machine. (I'm running a SurfaceBook 2 on the current non-Beta Windows 10.)

There are a lot of nice samples on running .NET Core and ASP.NET Core apps with Docker up at

I made a quick ASP.NET Core app called kubeaspnetapp:

C:\Users\scott\Desktop>dotnet new razor -o kubeaspnetapp
The template "ASP.NET Core Web App" was created successfully.
Restore succeeded.

Then added a two-stage build DockerFile that looks like this:

FROM microsoft/aspnetcore-build:2.0 AS build-env

# copy csproj and restore as distinct layers
COPY *.csproj ./
RUN dotnet restore

# copy everything else and build
COPY . ./
RUN dotnet publish -c Release -o out

# build runtime image
FROM microsoft/aspnetcore:2.0
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "kubeaspnetapp.dll"]

And built and tagged the image with:

C:\Users\scott\Desktop\kubeaspnetapp>docker build -t kubeaspnetapp:v1 .

Then I create a quick Deployment that manages a Pod that runs the Container:

C:\Users\scott\Desktop\kubeaspnetapp>kubectl run kubeaspnetapp --image=kubeaspnetapp:v1 --port=80
deployment "kubeaspnetapp" created

Now I'll expose it to the "outside." Again, this is usually done with .yaml files but it's a good learning exercise and it's all local.

C:\Users\scott\Desktop\kubeaspnetapp>kubectl get deployments
kubeaspnetapp   1         1         1            1           1m

C:\Users\scott\Desktop\kubeaspnetapp>kubectl get pods
NAME                             READY     STATUS    RESTARTS   AGE
kubeaspnetapp-778f6d49bd-rct59   1/1       Running   0          1m

C:\Users\scott\Desktop\kubeaspnetapp>kubectl expose deployment kubeaspnetapp --type=NodePort
service "kubeaspnetapp" exposed

C:\Users\scott\Desktop\kubeaspnetapp>kubectl get services
NAME            TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
kubeaspnetapp   LoadBalancer   <pending>     80:31756/TCP     5s
kubernetes      ClusterIP      <none>        443/TCP          1d

Then I'll hit in my browser...note how that port is brokering to the internal port 80 where the app listens...and there's my ASP.NET Core app running locally on Kubernetes, set up with Docker for Windows. Nice.

My ASP.NET Core app running in Kubernetes local on my Windows 10 machine

Here's me getting the startup logs from that pod:

C:\Users\scott\>kubectl get pods
NAME                             READY     STATUS    RESTARTS   AGE
kubeaspnetapp-7fd7f7ffb9-8gnzd   1/1       Running   0          6m

C:\Users\scott\Dropbox\k8s for pi\aspnetcoreapp>kubectl logs kubeaspnetapp-7fd7f7ffb9-8gnzd
Hosting environment: Production
Content root path: /app
Now listening on: http://[::]:80
Application started. Press Ctrl+C to shut down.

Pretty cool. As all the tooling and things across Windows, Docker, Kubernetes, Visual Studio (all flavors) continues to get better and better, I can only imagine this experience will get better and better. I look forward to a time when I can freely mix containers from different OSs and easily push them all en masse to Azure.

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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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Building a Raspberry Pi Car Robot with WiFi and Video

January 29, '18 Comments [12] Posted in Hardware | Open Source
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The SunFounder Raspberry Pi Car kit comes wtih everything you need except the 18650 batteries. You'll need to get those elsewhere.Last year I found a company called SunFounder that makes great Raspberry Pi-related kits and stuff. I got their Raspberry Pi 10" Touchscreen LCD and enjoyed it very much. This month I picked up the SunFounder PiCar 2.0 kit and built it with the kids. The kit includes everything you need except for the Raspberry Pi itself, a mini SD Card (the Pi uses that as  hard drive), and two 18650 rechargeable lithium batteries. Those batteries are enough to power both the Pi itself (so the car isn't tethered) as well as provide enough voltage to run the 3 servos AND motors to drive and steer the car around. You can also expand the car with other attachments like light sensors, line followers, and more.

The PiCar 2.0 includes the chassis, a nice USB WiFi adapter with antenna (one less thing to think about if you're using a Raspberry Pi  like me), a USB webcam for computer vision scenarios. It includes a TB6612 Motor Driver, PCA9685 PWM (Pulse Width Modulation) Servo Driver with 16 channels for future expansion. The kit also helpfully includes all the tools, screwdriver, wrenches, and bolts.

Preparing to build the SunFounder Raspberry Pi car

All the code for the SunFounder PiCar-V is on GitHub and while there can be a few hiccups with some of the English instructions, there are a bunch of YouTube videos and folks online doing the same thing so we had no trouble making the robot in a weekend.

Building a SunFounder Raspberry Pi Car

PRO TIP - Boot your new Raspberry Pi up with ssh enabled and already joined to your wifi

You'll need to use a tool like to burn a copy of the Raspbian operating system on to a mini SD card. I prefer to save time and avoid having to connect a new Raspberry Pi to HDMI and a mouse and keyboard, so I get the Pi onto my wifi network and enable SSH by copying these two files to the root of the file system of the freshly burned mini SD card. This will cause the Pi to automatically join your network when it boots up for the first time. Then I used Ubuntu on Windows 10 to ssh into the Pi and follow the instructions.

  • Make a 0 byte file called "ssh" and copy it to the root of the new PI disk
  • Make a file called "wpa_supplicant.conf" with just linefeeds at the end and make it look like this. Copy it to the root of the new PI disk.
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev


I like to use Notepad2 or Visual Studio Code to change the line endings of a file. You can see the CRLF or the LF in the status car and click it. Unix/Raspbian/Raspberry Pi likes just an LF (line feed) for the lineending, while Windows defaults to using CRLF (Carriage Return/Line Feed, or 0x13 0x10) for text files.

Changing the line endings to Unix

The default Raspberry username is pi and the default password is raspberry. You may want to change that. SunFounder has a decent "install_dependencies" script that you'll run on the Pi:

Installing the PiCar dependencies

Once you've built the PiCar you can ssh in and run their development server that gives you a little WebAPI to control the car. The SunFounder folks are pretty good at web development (less so with mobile apps) and have a nice Django app to control the PiCar.

Here's the view from the front camera of the PiCar as viewed through local website on port 8000. It's looking at my computer looking at itself. ;)

Viewing the PiCar camera through the Django website

You're able to control the PiCar from this web interface with the keyboard. You can move the car and steer with WASD, as well as move the head/camera independently. You will need to enter the settings area (upper right corner) and calibrate the back wheels direction. By default, one wheel may go the opposite direction because they can't be sure how you mounted them, so you'll need to reverse one wheel to ensure they both go in the same direction.

They also included a client application, also written in Python. On Windows you'll need to install Python, and when you run you may get an error:

ImportError: No module named requests

You'll need to run "pip3 install requests" as that module isn't installed by default.

Additionally, Python apps aren't smart about High-DPI displays, so I went to C:\Users\scott\appdata\local\Programs\Python\Python36 and right click'ed the Python.exe and set the DPI setting to "System (Enhanced)" like this.

Overridding DPI settings to System (Enhanced)

The client app is best for "Zeroing out" the camera and wheels, in case they are favoring one side or the other.


All in all, building the SunFounder "Raspberry Pi Video Car Kit 2.0" with the kids was a great experience. The next step is to see what else we can do with it!

  • Add a speaker so it talks?
  • Add Alexa support so you can talk to it?
  • Make the car drive around and take pictures, then use Azure cognitive services to announce what it sees?
  • Or, as my little boys say, "add weapons and make another bot for it to fight!"

What do you think?

* I use Amazon affiliate links and appreciate it when you use them! It supports this blog and sometimes gives me enough money to buy gadgets like this!

Sponsor: Unleash a faster Python! Supercharge your applications performance on future forward Intel® platforms with The Intel® Distribution for Python. Available for Windows, Linux, and macOS. Get the Intel® Distribution for Python Now!

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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Running BBS Door Games on Windows 10 with GameSrv, DOSBox, plus telnet fun with WSL

January 19, '18 Comments [20] Posted in Open Source
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Example of a BBS home screenI continue to enjoy seeing what can be done with WSL (Windows Subsystem for Linux) but even more fun is combining CMD.exe (the Windows console), Ubuntu on Windows (WSL), and DOSBox (an x86 emulator that lets you run OLD programs in original DOS that no longer run natively on Windows). What kind of cool stuff can I do today?

I did a lightning talk this week at NDC London where I started with a text file that included a CR/LF, Git autocrlf, then talked about typewriters, what a Carriage really is, then the Teletype Model 33, the Altair 8800, the ASCII chart, then ANSI art, and finally moved on to BBS's and BBS Door Games. I'll do a more extensive post later and I'm going to turn this into a full conference talk, but for the demo I ran a few BBS Door Games under Windows 10. Why? Because it's awesome and history is lovely.

You can try setting up what I'm going to describe in this post, or you can try telnet'ing to a BBS like the CaveBBS here: telnet:// You might also want to telnet:// for ASCII-based Star Wars! Originally we would call (like literally dial-up one to one) a BBS but ubiquitous internet added telnet as a nice option that persists today. Door Games were ASCII/ANSI games that the BBS would shell out to, passing the connection over. When the game extended, the BBS picked up the phone and kept the connection. TradeWars is/was the most well-known Door Game and we'd play it for months. TradeWars was the Elite Dangerous of the BBS set. ;)

So the question is, could we play DOS-based 16-bit Door Games today? Yes.

GameSrv can be used to bring your old DOS based BBS server into the new millennium. It'll act as a front-end and accept telnet connections before passing them off to the DOS BBS software.

Rick Parrish has a BBS door game server for Windows and Linux that he's written in open source C# called GameSrv. You may know Rick from his fTelnet browser based app. fTelnet lets you connect to Bulletin Board Systems from the comfort of your browser. A locally-run cross-platform option for connecting to BBS's is SyncTERM.

Go get SyncTerm, Rick's GameSrv Full, as well as DOSBox 0.73. You'll be able to telnet into your BBS with Ubuntu's (Bash on Windows/WSL) built in Telnet but you may run into issues with local echo (you'll want to Ctrl-] then type "mode char") as well as some missing extended ASCII characters that BBS's loved to draw menus with. While WSL's ANSI support is good, these missing characters cause hiccups. SyncTerm is totally custom with a whole host of Bitmapped fonts and a lot of custom work around extended control sequences. You should also try out EtherTerm, Qodem and NetRunner as other cool BBS-friendly terminal options.

NOTE: One of the major challenges of the conhost (console host - the thing that paints the console window and hosts and paints text and handles keyboard input for bash/cmd/powershell) is that while there's lots of great console fonts, those fonts don't often include some of the obscure extended ASCII DOS characters that BBS's used to draw their menus. In order to find and render those glyphs, consoles will use "font fallback" and follow a tree of fonts, looking for the best glyph. As I understand it (I could be wrong) the current conhost - lovely as it is - doesn't yet support this. I think it should in order to be a complete and effective solution for telnet/ssh/etc.

Run GameSrvConsole and it will listen on localhost by default. You could setup a VM in Azure and run it there to make your BBS and Door Games available to the public if you'd like! Then, either "telnet localhost" or run "syncterm localhost" to access your BBS. You can "ALT-ENTER" to put Sync Term full screen, which is awesome.

Your new BBS

Once you sign up for your BBS with a new account, you can try out the Door Games menu. Selecting a Door Game will cause GameSrc to launch DOSBox and run the Door, while brokering the output back to your telnet client.

Running a Door Game - Ambroshia Test of Time

I'm heartened to see 20 year old BBS Door Games come to live on Windows 10. I'm going to see if my 10 and 12 year olds get a kick out of some of these adventure games.

An adventure door game

Finally, and slightly related, try "curl" in a large WSL (Linux) console. Lovely. I love stuff like this. Perhaps I'm easily impressed, or I just miss ASCII art.


Head over to and STAR his GitHub Repository and if you like GameSrv and appreciate the work involved, you can donate to Rick as well. I have!

Sponsor: Get the latest JetBrains Rider for debugging third-party .NET code, Smart Step Into, more debugger improvements, C# Interactive, new project wizard, and formatting code in columns.

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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Trying out new .NET Core Alpine Docker Images

November 22, '17 Comments [20] Posted in Docker | DotNetCore | Open Source
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Docker ContainersI blogged recently about optimizing .NET and ASP.NET Docker files sizes. .NET Core 2.0 has previously been built on a Debian image but today there is preview image with .NET Core 2.1 nightlies using Alpine. You can read about the announcement here about this new Alpine preview image. There's also a good rollup post on .NET and Docker.

They have added two new images:

  • 2.1-runtime-alpine
  • 2.1-runtime-deps-alpine

Alpine support is part of the .NET Core 2.1 release. .NET Core 2.1 images are currently provided at the microsoft/dotnet-nightly repo, including the new Alpine images. .NET Core 2.1 images will be promoted to the microsoft/dotnet repo when released in 2018.

NOTE: The -runtime-deps- image contains the dependancies needed for a .NET Core application, but NOT the .NET Core runtime itself. This is the image you'd use if your app was a self-contained application that included a copy of the .NET Core runtime. This is apps published with -r [runtimeid]. Most folks will use the -runtime- image that included the full .NET Core runtime. To be clear:

- The runtime image contains the .NET Core runtime and is intended to run Framework-Dependent Deployed applications - see sample

- The runtime-deps image contains just the native dependencies needed by .NET Core and is intended to run Self-Contained Deployed applications - see sample

It's best with .NET Core to use multi-stage build files, so you have one container that builds your app and one that contains the results of that build. That way you don't end up shipping an image with a bunch of SDKs and compilers you don't need.

NOTE: Read this to learn more about image versions in Dockerfiles so you can pick the right tag and digest for your needs. Ideally you'll pick a docker file that rolls forward to include the latest servicing patches.

Given this docker file, we build with the SDK image, then publish, and the result is about 219megs.

FROM microsoft/dotnet:2.0-sdk as builder  

RUN mkdir -p /root/src/app/dockertest
WORKDIR /root/src/app/dockertest

COPY dockertest.csproj .
RUN dotnet restore ./dockertest.csproj

COPY . .
RUN dotnet publish -c release -o published

FROM microsoft/dotnet:2.0.0-runtime

WORKDIR /root/
COPY --from=builder /root/src/app/dockertest/published .
EXPOSE 5000/tcp
CMD ["dotnet", "./dockertest.dll"]

Then I'll save this as Dockerfile.debian and build like this:

> docker build . -t shanselman/dockertestdeb:0.1 -f dockerfile.debian

With a standard ASP.NET app this image ends up being 219 megs.

Now I'll just change one line, and use the 2.1 alpine runtime

FROM microsoft/dotnet-nightly:2.1-runtime-alpine

And build like this:

> docker build . -t shanselman/dockertestalp:0.1 -f dockerfile.alpine

and compare the two:

> docker images | find /i "dockertest"
shanselman/dockertestalp 0.1 3f2595a6833d 16 minutes ago 82.8MB
shanselman/dockertestdeb 0.1 0d62455c4944 30 minutes ago 219MB

Nice. About 83 megs now rather than 219 megs for a Hello World web app. Now the idea of a microservice is more feasible!

Please do head over to the GitHub issue here and offer your thoughts and results as you test these Alpine images. Also, are you interested in a "-debian-slim?" It would be halfway to Alpine but not as heavy as just -debian.

Lots of great stuff happening around .NET and Docker. Be sure to also check out Jeff Fritz's post on creating a minimal ASP.NET Core Windows Container to see how you can squish .(full) Framework applications running on Windows containers as well. For example, the Windows Nano Server images are just 93 megs compressed.

Sponsor: Get the latest JetBrains Rider preview for .NET Core 2.0 support, Value Tracking and Call Tracking, MSTest runner, new code inspections and refactorings, and the Parallel Stacks view in debugger.

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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Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.