.net core, Cake, Raspberry Pi 3

Running a .NET Core 2 app on Raspbian Jessie, and deploying to the Pi with Cake

I’ve managed to get .NET Core apps running on Windows 10 IoT Core, and on Ubuntu 16.04 (and also Ubuntu MATE), but until recently I’d never tried with Raspbian. I’ve read a few posts from people saying that they couldn’t get it to work, and a couple of nights ago I decided to bite the bullet and give it a go.

There’s a good post here on how to get the .NET Core runtime on a Raspberry Pi running Raspbian, and as always, there are a few tricks to getting things running from scratch. To augment this, I’ve created a “Hello World” application template for .NET Core Raspberry Pi on NuGet which I think will make things easier for the community.

At a very high level, the steps to getting a .NET Core 2 app on Raspbian are:

  • Install Raspbian onto an SD card and insert into your Raspberry Pi 3.
  • Set up SSH and test that you can log into your Raspberry Pi from your development machine.
  • Install .NET Core 2 onto the Raspberry Pi.
  • On your development machine, install the Raspberry Pi C# template for dotnet core.
  • Create a new console application using this template.
  • Deploy this application to your Pi running Raspbian using Cake.

I’ll run through each of these steps below.

Install Raspbian onto an SD card and insert into your Raspberry Pi 3

There are already great explanations of how to install the Raspbian OS onto a Raspberry Pi 3 – many people who have a Pi know how to do this already and I don’t really want to just repeat a well understood process here – so I’ve just put some useful links below:

Set up SSH and test that you can log into your Raspberry Pi from your development machine

Once you’ve set up Raspbian and booted your Pi to the desktop, you’ll need to allow SSH connections. These aren’t enabled by default but it’s very easy to configure this.

First open the main Raspberry Pi menu on your desktop as shown in the image below, and open the Preferences sub-menu to reveal the “Raspberry Pi Configuration” option.

2017-07-21-102129_1824x984_scrot

Open the “Raspberry Pi Configuration” option screen, and click on the “Interfaces” tab. There’s lots of useful settings here, but the one we want to enable is SSH – click on the “Enabled” radio button as shown below, and then click on OK. SSH is now enabled on your Pi.

2017-07-21-102157_1824x984_scrot

You’ll need to find the IP address of your Raspberry Pi – I think the easiest way is to open a terminal on your Pi and type:

hostname -I

This tells me that my Pi has the IP address 192.168.1.111.

Now we need to check you can log in from your development machine. I personally find it’s easiest to use PuTTY to do this. I’ve blogged about installing PuTTY before so I won’t repeat it all here – but a few tips are:

This bit is really important: When you install PuTTY using the installer, it ships with a couple of other programs – pscp.exe and plink.exe, which live in the same directory as putty.exe. You’ll need both of these to deploy the code to the Pi. Pscp.exe allows you to copy files from Windows to Linux, and plink allows you to remotely change permissions on the files you deploy.

It also makes life easier to add the putty installation directory to your machine’s path. If Cake doesn’t know where pscp and plink are on your machine, then you’ll probably see and error about unknown executables during deployment.

So open PuTTY, enter the Pi’s IP address and select the “Connection Type” to be SSH, as shown below:

screenshot.1500803365

When you click Open, a command prompt should open where you can type the username and password for the Pi 3.

screenshot.1500805617

The default username and password combo for Raspbian is “pi” and “raspberry“, and you should change the default password as soon as possible.

Install .NET Core 2 onto the Raspberry Pi

There’s a straightforward set of commands that you can run through PuTTY to install .NET Core 2 onto your Pi running Raspbian – I’ve written them below:

# Update the Raspbian Jessie install
sudo apt-get -y update

# Install the packages necessary for .NET Core
sudo apt-get -y install libunwind8 gettext

# Download the nightly binaries for .NET Core 2
wget https://dotnetcli.blob.core.windows.net/dotnet/Runtime/release/2.0.0/dotnet-runtime-latest-linux-arm.tar.gz

# Create a folder to hold the .NET Core 2 installation
sudo mkdir /opt/dotnet

# Unzip the dotnet zip into the dotnet installation folder
sudo tar -xvf dotnet-runtime-latest-linux-arm.tar.gz -C /opt/dotnet

# set up a symbolic link to a directory on the path so we can call dotnet
sudo ln -s /opt/dotnet/dotnet /usr/local/bin

Now you can test this install by running the dotnet –info command to see the version installed on Raspbian.

screenshot.1500810837

On your development machine, install the Raspberry Pi C# template

Now that we have .NET Core 2 installed on our Raspbian, we can go back to our development machine to create an application to run on the Pi.

First, install the template for creating Raspberry Pi applications

 dotnet new -i RaspberryPi.Template::*

This will create a new template available to dotnet core – you can list them all with the command:

dotnet new --list

And in the screenshot below, you can see there is now a new template called “Empty .NET Core IoT Project”, highlighted in red below.

screenshot.1500806357

Create a new console application using this template

It’s really easy to create a new console application now – just run the command below (obviously my application is called “HelloRaspbian”, but yours could be something different):

dotnet new coreiot -n HelloRaspbian

When you browse to this new application folder using your preferred development tool (mine is VSCode), you’ll see some files – we need to make a couple of changes.

First, run the command below to pull down the latest Cake build PowerShell file:

Invoke-WebRequest http://cakebuild.net/download/bootstrapper/windows -OutFile build.ps1

This command is also in the README.txt file which comes packaged with the application.

Now, open the build.cake file and you’ll see some defaults at the top of the file:

///////////////////////////////////////////////////////////////////////
// ARGUMENTS (WITH DEFAULT PARAMETERS FOR LINUX (Ubuntu 16.04, Raspbian Jessie, etc)
///////////////////////////////////////////////////////////////////////
var runtime = Argument("runtime", "linux-arm");
var destinationIp = Argument("destinationPi", "<>");
var destinationDirectory = Argument("destinationDirectory", @"<>");
var username = Argument("username", "<>");
var executableName = Argument("executableName", "HelloRaspbian");

Replaced those placeholders with the correct environment variables – I’ve shown my own settings below:

///////////////////////////////////////////////////////////////////////
// ARGUMENTS (WITH DEFAULT PARAMETERS FOR LINUX (Ubuntu 16.04, Raspbian Jessie, etc)
///////////////////////////////////////////////////////////////////////
var runtime = Argument("runtime", "linux-arm");
var destinationIp = Argument("destinationPi", "192.168.1.111");
var destinationDirectory = Argument("destinationDirectory", @"/home/pi/DotNetConsoleApps/RaspbianTest");
var username = Argument("username", "pi");
var executableName = Argument("executableName", "HelloRaspbian");

I’ve created a folder on the Pi to deploy my application to, using the command below at the PuTTY SSH prompt at my home directory (/home/pi/).

mkdir -p DotNetConsoleApps/RaspbianTest

Deploy this application to your Pi running Raspbian using Cake

Once I’ve replaced the placeholders in my Cake file, the only thing left to do is run the build.ps1 file from a PowerShell prompt.

screenshot.1500811107

To test this, go back to the PuTTY SSH prompt and navigate to your home directory and run:

./DotNetConsoleApps/RaspbianTest/HelloRaspbian

And you’ll get a text output saying “Hello Internet of Things!”

screenshot.1500810451

Wrapping up

I hope this post is useful to anyone trying to get a C# console application running on Raspbian. I think Raspbian is the default OS for Raspberry Pi users, so this should open up many development opportunities. My Raspberry Pi template makes creating the default console application easier, and Cake is a brilliant way to orchestrate the deployment process (rather than dragging and dropping files using tools like WinSCP, and having to change file permission manually). I’ll be blogging more on the future on deploying IoT applications to this platform.

I’ve written a few posts now about how to deploy C# Raspberry Pi applications to Windows 10 IoT Core, Ubuntu, and Raspbian (all using Cake as the orchestration tool) – next time I’ll write about how to use Cake to automatically build a UWP AppxBundle and deploy that AppxBundle to Windows 10 IoT Core.


About me: I regularly post about .NET – if you’re interested, please follow me on Twitter, or have a look at my previous posts here. Thanks!

19 thoughts on “Running a .NET Core 2 app on Raspbian Jessie, and deploying to the Pi with Cake

  1. Thanks for the description. Please add single quotes around the wget URL parameter. It took me 20 minutes to figure out why it didn’t work. Best regards, Tom

    1. Sorry to hear that Tom. I double checked here and it works fine without quotes. What’s your SSH tool, or are you doing this directly on a Pi terminal or something?

  2. It’s scary how timely this was! I just today needed to get rolling with a new .net core app on the RPi 3, got my Pi in the mail just now (7/24/2017) and here’s your article. Thanks for the great kickstart!!

      1. I did hit a speedbump at the end: I could not get the simple hello world app to build and produce an executable. the .dll came out, but the Cake deploy step complained that there was no executable. I ensured I had .Net Core 2 preview 2 installed, but still no dice. I’ve got stock visual studio 2017, but will shortly have 2017 v15.3 installed and try that. Any hints/suggestions on getting my build done besides the above? 🙂 thanks again much for lighting the way.

        1. I’ve only used PowerShell and VSCode, so there shouldn’t be a dependency on VS2017. Do you mind if I drop you an email to correspond, maybe we can diagnose the issue together – I’ll post the resolution as a reply here once we work it out?

          1. Just to update for any future readers – the issue was Cake couldn’t find PSCP.exe to deploy files from Windows to Linux. I’ve updated the blog with instructions on how to get this program.

  3. Thanks for the article. But I have problem with Deploy, after execute script I got error:
    An error occurred when executing task ‘Deploy’.
    Error: Pscp: Could not locate executable.
    I have also tried connect to raspbbery by Putty and it works fine.
    I use rapsbian system.
    Do you have any idea what is wrong?

    1. Hey – sounds like you don’t have PSCP on your machine, or it’s not on the path. Do you have a file called “pscp.exe” in your “C:\Program Files\PuTTY” directory? And if you type pscp at a command prompt (not in that folder) do you get a message about “PuTTY Secure Copy client”?

      1. @Bartosz I was having the same issue, Jeremy suggested adding this to the top of the cake.build file, which resolved my issue w/out adding PuTTY to the path:

        Setup(context => {
        context.Tools.RegisterFile(@”C:\Program Files\PuTTY\pscp.exe”);
        context.Tools.RegisterFile(@”C:\Program Files\PuTTY\plink.exe”);

        });

        Setting path to wherever yours is located.

        1. Thanks this was helpful to get pscp.exe working, but I am now getting a “permission denied” even though I am able to login with Putty.exe via SSH from my development workstation.

  4. I’m not sure I got it right. When I put “dotnet” in the console I get a Segmentation fault. I followed your steps all the way until I hit the “dotnet –info” step. Any ideas? Sounds like either dotnet itself has a bug or more likely I missed a pre-req. But I followed your scripts to the letter.

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