1.
MSBuild
> Martin Ullrich, @dasMulli

2.
© CSS GmbH | 2016
About myself
Martin Ullrich - @dasMulli
 Software Engineer at CSS
– C#/.NET, iOS (ObjC/Swift), Java, Frontends, …
– Cares about Build Automation, CI / CD
 Somewhat active on .NET Core GitHub Repos
 Learned MSBuild in 2016
2

3.
© CSS GmbH | 2016 3

4.
© CSS GmbH | 2016
AGENDA
 Overview and Context
 How it works
 Diagnosing Issues
 Demos - Tips and Tricks
 Ask Me Anything
4

5.
© CSS GmbH | 2016
GOALS
 Never use „xcopy“ in build events again
 Have an easier time navigating .csproj files
5

6.
MSBuild
“The 2003 Format”
6

7.
© CSS GmbH | 2016
project.json 😢
7
{
"version": "1.2.3",
"dependencies": {
"Newtonsoft.Json": "10.0.1"
},
"frameworks": {
"netcoreapp1.0": {
"dependencies": {
"Microsoft.NetCore.App": {
"type": "platform",
"version": "1.0.0"
}
}
}
}
}

8.
© CSS GmbH | 2016
The Reality
8

9.
© CSS GmbH | 2016
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
9

10.
© CSS GmbH | 2016
Other dotnet CLI issues
 Re-implemented many MSBuild features
– Incremental compilation
– Configuration management
 NuGet packages containing MSBuild logic no longer work
 Bugs
 Visual Studio: UI over project.json
 OmniSharp & others: separate handling
10

11.
© CSS GmbH | 2016
Build Systems
11
DSL
”flexible”
Code
MSBuild
project.json
Gradle
Grunt
Gulp
Maven
Cake

12.
© CSS GmbH | 2016
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
12

13.
© CSS GmbH | 2016
Tooling - IDEs
 Visual Studio
 OmniSharp
– Visual Studio Code
– Atom, Vim, …
 Visual Studio for Mac
 Rider
 3rd party tools
– E.g. dotnet-outdated
13

14.
© CSS GmbH | 2016
Visual Studio: Project Systems
14
Source: https://github.com/dotnet/project-system

15.
© CSS GmbH | 2016
Visual Studio: Project Systems
 csproj.dll, msvbproj.dll
– Native, COM-based
– Single-threaded, bound to UI Thread
– Super hard to extend
 “the new project system” – dotnet/project-system
– Managed
– Multi-threaded, scalable, responsive
– Easier to extend via MEF / managed code
– Parts of it are VS-independent
– Developed on GitHub
15

16.
© CSS GmbH | 2016
MSBuild 101
 XML Format
 Definitions + Logic
– Can look like a DSL
 "Variables”, “Lists”
 Conditions, Loops  Control Flow
 Is it a programming language?
16

17.
Hello MSBuild - Code
17

18.
© CSS GmbH | 2016
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
18

19.
© CSS GmbH | September 2014
Properties vs. Items
 Key-Value Pair
 “Variable”
 Single Value
 Environment Variables are
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 19

20.
© CSS GmbH | 2016
Properties
$(MyProperty)
20

21.
© CSS GmbH | 2016
Items
@(MyItems)
 MyItemA;MyItemB
@(MyItems->’%(Identity).old’)
 MyItemA.old;MyItemB.old
@(Person->’%(LastName)’, ‘ - ‘)
 Ullrich – Doe
21

22.
© CSS GmbH | 2016
Warning: Static Evaluation
 All project XML is scanned before targets run
– “Static Evaluation”
 Order is important here:
1. Properties and Imports
2. Item definitions
3. Items
 Allows for a few ”default item” features
– EnableDefaultItems
– EnableDefaultCompileItems
– …
22

23.
© CSS GmbH | 2016
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>
23

24.
© CSS GmbH | 2016
Targets
 Contain actual build logic
 Contains tasks
– Property and Item Groups are “intrinsic tasks”
 Targets can have dependencies
–  Graph
 Targets can define Inputs and Outputs
– Enbales incremental builds (skipping targets)
– Newest timestamps of Inputs and Outputs are compared
24

25.
© CSS GmbH | 2016
Project SDKs
 Automatic Imports
 SdkResolvers try to find the SDK
– Name or Name/Version
– On disk or NuGet
 “SdkSdk.props” and “SdkSdk.targets” will be imported
automatically
 Import tag also supports Sdk attribute
25

26.
© CSS GmbH | 2016
Restore
 dotnet msbuild "-t:Restore;Build”
– Can fail due to XML caches
 dotnet msbuild -restore -t:Build
– Runs the “Restore” target before the actual build
– Clears all MSBuild caches in between
26

27.
Diagnostics?
27

28.
© CSS GmbH | 2016
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
– http://msbuildlog.com
28

29.
Demo time
29

30.
© CSS GmbH | 2016
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
30

31.
Questions
31

32.
© CSS GmbH | 2016
Frequent Questions
 What about Pre-/Post-build events in SDK projects?
 How do I enable binding redirects generation?
– Why do I need them for .NET Standard libraries?
 Why does my project have so many dependencies?
 .NET Core 2.1 shared fx roll-forward.
– a.k.a. <TargetLatestRuntimePatch>
 Where do I get help with severe build errors?
32

33.
© CSS GmbH | 2016
Some Links
https://github.com/Microsoft/msbuild
https://docs.microsoft.com/en-us/visualstudio/msbuild/msbuild
https://github.com/dotnet/sdk
https://github.com/aspnet/websdk
https://docs.microsoft.com/en-us/dotnet/core/tools/csproj
33