1. Martin Ullrich @dasMulli
MSBuild
Martin Ullrich
@dasMulli

2. Hi, I’m Martin @dasMulli Martin Ullrich Martin Andreas Ullrich
Senior Consultant at Tieto Austria
Software Engineer
C#/.NET, iOS (ObjC/Swift), Java, Frontends, …
Cares about Build Automation, CI / CD
Somewhat active on .NET Core GitHub Repos
Learned MSBuild in 2016
@dasMulli
Martin Ullrich

4. Agenda Overview and Context How it works Diagnosing Issues
Demos - Tips and Tricks
Questions, Questions, Questions

5. Goals Never use „xcopy“ in build events again
Have an easier time navigating .csproj files

6. MSBuild: “The 2003 Format”

7. Project.json 😢 { "version": "1.2.3", "dependencies": {
"Newtonsoft.Json": "10.0.1” },
"frameworks": {
"netcoreapp1.0": {
"Microsoft.NetCore.App": {
"type": "platform",
"version": "1.0.0" }

8. The Reality

9. Why didn’t project.json save us all?
.csproj too complicated back then
Chicken or the egg problem
How do I migrate 100 projects?
.NET Standard projects need to be referenced by existing projects.
“.xproj”
Visual Studio and existing tools are built around MSBuild
Limited extensibility

10. Other dotnet CLI issues
Re-implemented many MSBuild features
Incremental compilation
Configuration management
NuGet packages containing MSBuild logic no longer work
Missing Features / Edge cases / Bugs
Visual Studio: UI over project.json
OmniSharp & others: separate handling

11. Build Systems ”flexible” DSL Code Gulp Grunt project.json Gradle
MSBuild
Maven
Cake

12. New Console App – Classic csproj

13. New Console App – “SDK-style” csproj

14. MSBuild 15 Open Source 🎉 - https://github.com/Microsoft/msbuild
Runs on .NET Core and Mono
Replaces xbuild on Mono
Syntactic sugar
SDKs, Metadata Attributes for Items, …
Automatically discovered files
Directory.Build.(props|targets|rsp)
Performance Improvements
More Features & Functionality on each minor release

15. Tooling - IDEs Visual Studio OmniSharp Visual Studio for Mac Rider
Visual Studio Code
Atom, Vim, …
Visual Studio for Mac
Rider
3rd party tools
E.g. dotnet-outdated

16. Visual Studio: Project Systems

17. Visual Studio: Project Systems
csproj.dll, msvbproj.dll
Native, COM-based
Single-threaded, bound to UI Thread
“the new project system” – dotnet/project-system
Managed
Multi-threaded, scalable, responsive
Developed on GitHub
Some Features may or may not work yet

18. MSBuild 101

19. MSBuild 101 XML Format Definitions + Logic "Variables”, “Lists”
Can look like a DSL
"Variables”, “Lists”
Conditions, Loops  Control Flow
Is it a programming language?

20. MSBuild 101: Code Demo

21. Project Files Any XML file can be an MSBuild project
.props / .targets are only a loose convention
.props = Beginning of files / contain defaults
.targets = End of files / build logic
MSBuild command line looks for *.*proj files by default

22. Properties vs. Items Key-Value Pair “Variable” Single Value
Environment Variables are Properties
Well-Known Properties
Global Properties
Can override definition in project file
Collections
“Lists”
Identity + Metadata
Duplicates are possible
May represent files on disk
 Glob Patterns
Used for Batching
“Loops”, “Group By”
Item Definition
 Default Metadata

23. Properties
$(MyProperty)

24. Items @(MyItems)  MyItemA;MyItemB @(MyItems->’%(Identity).old’)
 MyItemA.old;MyItemB.old
@(Person->’%(LastName)’, ‘ - ‘)
 Ullrich – Doe

25. Warning: Static Evaluation
All project XML is scanned before targets run
“Static Evaluation”
Order is important here:
Properties and Imports
Item definitions
Items
Allows for a few ”default item” features
EnableDefaultItems
EnableDefaultCompileItems …

26. Property Functions MSBuild allows calling .NET code
Built-In functions
Some select .NET Types
<NewGuid>$([System.Guid]::NewGuid())</NewGuid>
<Sum>$([MSBuild]::Add($(CommitCount), 2))</Sum>
<IsBeta>$(Version.EndsWith(‘beta’))</IsBeta>

27. Targets Contain actual build logic Only run once Contains tasks
Property and Item Groups are “intrinsic tasks”
Targets can have dependencies
 Graph
Targets can define Inputs and Outputs
Enables incremental builds (skipping targets)
Newest timestamps of Inputs and Outputs are compared

28. Project SDKs Automatic Imports SdkResolvers try to find the SDK
Name or Name/Version
On disk or NuGet
On disk: .NET Core CLIs with compatible MSBuild versions
“Sdk\Sdk.props” and “Sdk\Sdk.targets” will be imported automatically
Import tag also supports Sdk attribute

29. Diagnostics?

30. So you just hit a build error…
Logs are your best friend
Verbose logs: msbuild -flp:verbosity=diag
Binary logs (15.3+): msbuild -bl
Embeds project file contents
Super helpful for looking at issues without the source
Structured Log Viewer

31. Project File Demos

32. More Demos?

33. Demo Menu Publish for multiple target frameworks
Using ”MSBuild Scripts” for your CI pipeline
1 Directory, multiple SDK-style csproj files
Include referenced Projects in NuGet package
Ship your build logic as NuGet packages
+ Create your own “Project SDK”
Create inline MSBuild Tasks with RolsynCodeTaskFactory
Creating a cross-platform MSBuild Task

34. Questions?

35. Useful Links https://github.com/Microsoft/msbuild
MSBuild reserved and well-known properties
MSBuild well-known item metadata
Common MSBuild project properties
Common MSBuild project items
Additions to the csproj format for .NET Core