net core blimey! (shropshire devs mar 2016)
TRANSCRIPT
This is Matt Ellis
He works for Microsoft, and is a developer on the .NET Core team.
This is not me.
What is .NET Core?
New .NET stack - CLR + BCL
Open SourceCross platform
Standalone -per-application installs
Factored for modularity - “cloud optimised”
Everything ships as NuGet packages,
including the runtime
Not finished…RTM Q1 2016 (ish)
.NET Core != .NET Framework
NOT a new version of the .NET Framework
• .NET Framework is going nowhere
• .NET Core is 5.0 1.0.NET Framework is 4.6
• .NET Core is a fork of the .NET FrameworkCode merged back to TFS
• .NET Core is (currently) a strict subset of the .NET Framework
• Missing pieces in .NET CoreWindows: WinForms, WPF, COM, etc.Platform: AppDomains, Remoting, Reflection.Emit, etc.
• Different constraints:Ship cycles, compatibility, system wide install
Why?
Multiple .NET stacks. Incompatibilities
Portable Class Librariesnot scalable
Cross platform
Independent release cyclesRuntime, BCL, apps
Nano Server
Tidy up15 years of evolution
Why?
Multiple .NET stacks. Incompatibilities
Portable Class Librariesnot scalable
Cross platform
Independent release cyclesRuntime, BCL, apps
Nano Server
Tidy up15 years of evolution
How do I get it?
.NET CLI tools (née DNX)
Official installer from dotnet.github.io
dotnet.exe, compilers (csc, vbc, fsc, ilc), NuGet,own .NET Core instance (runtime + fx)
dotnet.exe is a driver for other commandse.g. dotnet foo simply executes dotnet-foo
No more dnvm - runtime is genuine NuGet dependency now(“runtime.osx….” packages)
Global package cache
dotnet compile dotnet-compilednvm
runtime.osx.…
dotnet.exe
CoreRT (née .NET Native)
Alternative runtime (optimisation)
• AOT compilation (RyuJIT → Native)
• Compiles all dependenciesTree shaking
• Reflection? Via xml!
• Open Source (dotnet/corert)
• Previously Windows Store onlyNow includes Mac + Linux (!)
• ILtoCPP - IL → C++ → nativeLLILC - LLVM based JIT/AOT
dotnet/coreclr
JIT compiler (RyuJIT), Garbage Collector, Platform Abstraction Layer - C++
mscorlib (tightly coupled to runtime) - C#
PAL - OS and platform differences. E.g. exception handling, threads, etc.P/Invoke to OS, FEATURE #ifdefs
Book of the Runtime!
Mirror back to TFS
dotnet/corefx
Factored for modularity - each solution/assembly is a package
Some platform specific implementations, e.g. System.Console, Process.Interop.Unix.cs, etc.
Might throw PlatformNotSupportedException(e.g. Console.get_ForegroundColor )
Build is based on project.json, packages as references
Mirrored to TFS + .NET Framework
High compatibility bar for changes, transparent API review process
Console.get_ForegroundColorPlatformNotSupportedException
How the application is hosted and run
Environmental services
What is an AppModel?
Bootstrap the CLR Execute the application
.NET Framework AppModels
.NET .exe
Originally a native stub that loaded the CLR (x86 only!)
Special cased by OS loader since Windows XP
Loads mscoree.dll, which initialises CLR and executes
app
IIS/asp.net
Pre-IIS 7 - ISAPI filter
IIS 7 directly integrates CLR
Pipes requests/responses to managed code
Lifetime management
Windows Phone / Windows Store
Magic!
“Application host” loads CLR
Integrates with environment events. E.g. suspend and
resume applications
Pre-compiled / .NET Native
.NET CLI (née DNX)
Dot NET Execution Environment
started with ASP.NET Core
Targets .NET Core /.NET Framework /
Mono
Self contained .NET Core environment
Changes project system Reference packages, not assemblies
More…
• Packages for runtime and BCL
• BCL factored into many packages
• NuGet at heart of project system (project.json/.xproj)
• .NET Standard Platform
• NuGet is the new Portable Class Library
NuGet
.NET Standard Platform
How does it work?
.NET Core app.NET Core package
PCL package
.NET Framework package
.NET Framework app?
PCL Refresher
1. A PCL is a class library that needs to run on multiple platforms and versions(e.g. .NET Framework, Windows Phone, Xamarin)
2. It defines a common subset of APIs that are available on ALL of the required versions of these platforms - a “Profile”
3. When targeting a Profile, the compiler references a set of Reference AssembliesThese describe the API with empty types, and forward types to correct assemblies
4. At runtime, the real assemblies on the target platform implement the APIs Can also forward types to other assemblies
Portable Class Libraries
• PCL hides platform specific implementation details behind a common API contract (reference assembly)
• Reference assemblies allow moving implementations to other assemblies
• Profiles do not scale. The more versions and platforms, the more Profiles…
• A published PCL lists all supported platforms (e.g. portable-win+net40+wp)If a new platform is created, it isn’t supported
• Profiles need to be installed How does this work in the app-local, NuGet-based .NET Core world?
Reference Assemblies in .NET Core
• Allows for different implementations on different platforms and operating systems, but common API
• Allows for refactoring the BCL!
• Reference assemblies shipped in NuGetpackages in \ref folder
• Consuming a package will use thereference assembly at compile time, butimplementation assembly at runtime
\ref
.NET Standard Platform
• A new, versioned, abstract platform that all other platforms can map to
• An app/lib can target a version of the .NET Standard PlatformCan consume any package from any platform that is compatible with that version of the .NET Standard Platform
• E.g. .NET Framework 4.5.2 maps to .NET Standard Platform 1.2A .NET Framework 4.5.2 app/lib can consume any package that targets any platform that maps to .NET Standard Platform 1.2 or earlier
• NuGet knows the mapping E.g. lib\net452 is same as lib\netstandard1.2 , as is
• Equivalent of the PCL profile, but less explicit
lib\net452 lib\netstandard1.2 lib\wpa81
Platforms
• All platforms conform to a specific version of the .NET Standard Platform
• Packages can target a concrete platform (e.g. lib/net46 ) or a specific version of the .NET Standard Platform (e.g. lib/netstandard1.3 ). Or both!
• NuGet understands mappings between real platforms and netstandard versions (and PCLs)
• Can consume any compatible platform
• Replaces PCLs with a single versioned moniker. Creating a new platform is easy
• Only works with .NET Framework ≧ 4.5!
lib\net46lib\netstandard1.3
netstandard
How does this affect us?
Creating NuGet packages
Target netstandardif possible
Specify .NET Standard Library dependency?
Explicitly specify used dependencies?
Version of dependencies is irrelevantImplied by .NET Standard Platform
Include PCL andreference assembly
if required
New Target Framework Monikers
Brand new
• dotnet - - .NET Core contracts. Replaces portable- . Use this!Supports .Net Framework 4.5 and later (inc. Xamarin)
• dnx451 , dnx46 - - Application running on .NET CLI
• uap10.0 - Windows 10 apps(Confusingly AKA , following on from netcore45 / win8 and netcore451 / win81)
netstandard1.X
netstandardapp1.X
netcore50 netcore45 win8netcore451 win81
uap10.0
portable-*
What does this mean for Mono?
Lots. Or not much.
Mono == .NET FrameworkMono already cross platform
Mono’s focus is non-Windows
mobile (Xamarin)
.NET Core’s focus is server and
Windows UWP
Mono can include CoreCLR + CoreFX
code
Where does Roslyn fit in?
Orthogonal.
Runs on .NET Framework + Mono
Ships with .NET CLIrunning on .NET Core
Compiling CoreCLR + CoreFXcurrently requires Windows/Mono
C# compiler written in C#
.NET Core
Cross platform
Open Source
NuGet everywhere
Bleeding edge (but getting there)
Icons: http://icons8.com/
The future of .NET
Links
CoreCLR - https://github.com/dotnet/coreclr
CoreFX - https://github.com/dotnet/corefx
CoreRT (.NET Native) - https://github.com/dotnet/corert
.NET CLI - https://github.com/dotnet/cli
NuGet - http://docs.nuget.org
@citizenmatt