eerhardt
commented
1 year ago @reyang @cijothomas @CodeBlanch - I ran into this issue as well trying to use Open Telemetry in an ASP.NET app. We want to enable ASP.NET + NativeAOT in .NET 8.0. See https://github.com/dotnet/aspnetcore/issues/45910. Ensuring Open Telemetry works in these NativeAOT ASP.NET apps is part of this goal.
The issue is this following code:
This is not NativeAOT-compatible since it using Reflection to MakeGenericType on the ContextSlotType. The NativeAOT compiler has no idea that it needs to generate native code for the AsyncLocalRuntimeContextSlot<int> type. And thus we get an exception at runtime above.
You also get warnings about this method when you publish with -p:PublishAot=true.
ILC : Trim analysis warning IL2055: OpenTelemetry.Context.RuntimeContext.RegisterSlot<T>(String): Call to 'System.Type.MakeGenericType(Type[])' can not be statically analyzed. It's not possible to guarantee the availability of requirements of the generic type. [C:\DotNetTest\Net8Api\Net8Api.csproj]
ILC : AOT analysis warning IL3050: OpenTelemetry.Context.RuntimeContext.RegisterSlot<T>(String): Using member 'System.Type.MakeGenericType(Type[])' which has 'RequiresDynamicCodeAttribute' can break functionality when AOT compiling. The native code for this instantiation might not be available at runtime. [C:\DotNetTest\Net8Api\Net8Api.csproj]
ILC : Trim analysis warning IL2075: OpenTelemetry.Context.RuntimeContext.RegisterSlot<T>(String): 'this' argument does not satisfy 'DynamicallyAccessedMemberTypes.PublicConstructors' in call to 'System.Type.GetConstructor(Type[])'. The return value of method 'OpenTelemetry.Context.RuntimeContext.ContextSlotType.get' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to. [C:\DotNetTest\Net8Api\Net8Api.csproj]What can we do to solve this? We need to not use MakeGenericType, and instead have a static call to the RuntimeContextSlot<T> that we are trying to create.
Do we really need the full extensibility of public static Type ContextSlotType { get; set; }? Would it be acceptable to remove that API and instead have a static enum that could be set for the 3 types of context slots? Then RegisterSlot could look something like:
public enum ContextSlotType
{
AsyncLocal,
ThreadLocal,
Remoting
}
...
public static RuntimeContextSlot<T> RegisterSlot<T>(string slotName)
{
Guard.ThrowIfNullOrEmpty(slotName);
lock (Slots)
{
if (Slots.ContainsKey(slotName))
{
throw new InvalidOperationException($"Context slot already registered: '{slotName}'");
}
RuntimeContextSlot<T> slot = ContextSlotType switch
{
ContextSlotType.AsyncLocal => new AsyncLocalRuntimeContextSlot<T>(slotName),
ContextSlotType.ThreadLocal => new ThreadLocalRuntimeContextSlot<T>(slotName),
#if NETFRAMEWORK
ContextSlotType.Remoting => new RemotingRuntimeContextSlot<T>(slotName),
#endif
_ => throw new NotSupportedException($"{ContextSlotType} is not supported."),
};
Slots[slotName] = slot;
return slot;
}
}cc @LakshanF @agocke @tarekgh
cijothomas
reyang
agocke
utpilla
alanwest
TheXenocide
Yun-Ting
missisjana
Bug Report
When publishing my app with
dotnet publish --self-contained -p:PublishAot=true -r win-x64 -o outand then running it, the app crashes on startup with an open telemetry stack:libraries:
more information: https://docs.microsoft.com/en-us/dotnet/core/deploying/native-aot