Over the past few months, we’ve had a number of questions and requests for better support around building and packaging .NET Core applications. We’ve had support for that for quite a while, but what has been interesting is the number of requests for supporting building .NET Core applications on .NET Core. What does that mean exactly? It means supporting building .NET Core applications on machines that only have .NET Core, and not the full .NET framework. Think Linux or Mac OS machines.
If that’s a space you’re working in or looking to move into we’ve got some exciting news. Along with all of the other exciting things included in 2018.7, we’ve updated
octo.exe so you can now access it as a .NET command-line extension.
Introducing dotnet octo
For some time now,
octo.exe has been cross-platform, with support for running on both .NET Framework and .NET Core. However, it’s been awkward executing
octo.exe while doing a build on a .NET Core only platform.
dotnet octo global tool. It does everything
octo.exe does, but it can be called using
dotnet octo <command>. This provides a convenient way to get
octo.exe onto any machine that has the latest dotnet SDK version available.
To work the magic, summon
octo.exe onto your build machine using the following:
dotnet tool install Octopus.DotNet.Cli --tool-path /path/to/install
Then to awaken
octo.exe from its slumber invoke classic incantations such as
dotnet octo pack and
dotnet octo create-release.
Just as a note on the
tool-path argument, you can replace that with the --global flag and it will install the tool globally. Depending on your build machine configuration, installing globally possibly isn’t a good idea though, installing locally to the folder the build is running in provides better isolation. Unfortunately, the isolation comes with a minor wrinkle where the dotnet command-line doesn’t provide the same argument to help find the tools you’ve put into custom tool paths. To get around this, you have to ensure the path is added to the environment Path variable.
Also note, the above summons the latest version onto your build machine. There is a version switch if you want finer control.
So what would a build script that brings all of this magic together look like? Here’s a simplified example:
dotnet publish MyAwesomeWebApp -o myMarshallingFolder dotnet octo pack --id=MyAwesomeWebApp --version=22.214.171.124 --outFolder=myArtifactsFolder --basePath=myMarshallingFolder dotnet octo push --package=myArtifactsFolder\MyAwesomeWebApp.126.96.36.199.nupkg --server=https://my.octopus.url --apiKey API-XXXXXXXXXXXXXXXX
Like I said, this is simplified. When you’re setting this up from your favorite build tool, you might want to split it into three separate steps.
Runtime and SDK requirements
In order to use Octo as described here, you must use the .NET Core SDK
2.1.300 or newer.
Our TeamCity extension will already handle switching between
dotnet octo, so you shouldn’t need to change anything in your existing steps for
create-release etc. You will have to work out a strategy for the
dotnet tool command. You could run that as a script at the beginning of your build process, or you could have it pre-run on your build agents. Also coming very soon to the TeamCity extension is a separate
pack step, for those who want to pack and then use a feed other than Octopus’s built-in feed (e.g. TeamCity’s feed or Artifactory).
The v3.0 update of the VSTS extension includes the updates to support using
dotnet octo. The changes include a move away from using PowerShell, which makes it compatible with build agents running operating systems like Linux.
But what about OctoPack?
There’s one more thing to cover in this post. The elephant in the room, if you will. What about OctoPack?
The short answer is that OctoPack relies on some mechanics of NuGet and MSBuild that have changed in the .NETCore world and trying to port it to work in this new world doesn’t seem like it would provide value over using
One of the key parts here, is the application formats we now support. Back when OctoPack came to be, it had two key application types to worry about. Web apps and Windows apps. Both of these can be packaged by simply grabbing the binary outputs and any files marked as content (this is what OctoPack does internally when building a nuspec file).
Fast forward to today, and we have application formats like Cloud Services and Service Fabric. Supporting the ever growing number of these formats isn’t practical in OctoPack, so we recommend using the
package target that’s built into VS/MSBuild. There’s an example of how to do this in our documentation.
The one caveat to this is that
Octopus.Client for it’s
push command, so it is limited to only pushing to the Octopus built-in feed. If you need to push to another package service, you will need to use
NuGet.exe rather than
octo.exe. We’re looking at options to address this.
The .NET Core world is still a fast moving place, so this is a step in what I’m sure will be a longer journey. If you’re building .NET Core applications, please give
dotnet octo a spin and give us feedback below to help guide that journey.
- Guide: How to deploy an ASP.NET web app to Azure
- Setting up your own cloud-based CI/CD pipeline Using AppVeyor and Octopus to deploy an ASP.NET Core web app
- Build Pipelines and Application Packaging With .NETCore
- Documentation: Packaging Applications
- Documentation: Versioning
- Deploying an ASP.NET Core web app to Linux