Add support for logging with more than 6 arguments at runtime

[maryamariyan]

Background and Motivation

As part of .NET 6 we updated the new LoggerMessage.Define overloads to use LogDefineOptions. (PR here and issue https://github.com/dotnet/runtime/issues/50913)

Later in .NET 7, for supporting more arguments, we could add a new Define<T> API (where T is a delegate) that would take n arguments, log level, event ID, format string and LogDefineOptions to log message.

Theoretically we need an analyzer that makes sure the arguments of the new Define API are proper (ILogger etc.). The source generator would not be using the new Define (where T is delegate) API. (not source gen friendly).

We welcome API proposals! We have a process to evaluate the value and shape of new API. There is an overview of our process . This template will help us gather the information we need to start the review process. First, please describe the purpose and value of the new API here.

Proposed API

Something like:

public static partial class LoggerMessage
{
+    public static void Define<T>(Microsoft.Extensions.Logging.LogLevel logLevel, Microsoft.Extensions.Logging.EventId eventId, string formatString, Microsoft.Extensions.Logging.LogOptions options) where T : delegate {​ throw null; }​
}

T would be a delegate but an analyzer would need to make sure it takes ILogger, Exception, etc. System.Action<Microsoft.Extensions.Logging.ILogger, T1, T2, ..., Tn, System.Exception?>

TODO

• [ ] Go through the Framework Design Guidelines and API Review Process to further investigate sample usages and investigate alternative designs and risks.

cc: @davidfowl @eerhardt

[ghost]

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Issue Details

---

## Background and Motivation As part of .NET 6 we updated the new `LoggerMessage.Define` overloads to use `LogDefineOptions`. (PR [here](https://github.com/dotnet/runtime/pull/54581) and issue [here](https://github.com/dotnet/runtime/issues/52276)) Later in .NET 7, for supporting more arguments, we could add a new `Define` API (where T is a delegate) that would take n arguments, log level, event ID, format string and `LogDefineOptions` to log message. Theoretically we need an analyzer that makes sure the arguments of the new Define API are proper (ILogger etc.). The source generator would not be using the new Define (where T is delegate) API. (not source gen friendly). We welcome API proposals! We have a process to evaluate the value and shape of new API. There is an overview of our process . This template will help us gather the information we need to start the review process. First, please describe the purpose and value of the new API here. ## Proposed API Something like: ```diff public static partial class LoggerMessage { + public static void Define(Microsoft.Extensions.Logging.LogLevel logLevel, Microsoft.Extensions.Logging.EventId eventId, string formatString, Microsoft.Extensions.Logging.LogOptions options) where T : delegate {​ throw null; }​ } ``` `T` would be a delegate but an analyzer would need to make sure it takes ILogger, Exception, etc. `System.Action` ## TODO - [ ] Go through the [Framework Design Guidelines](https://github.com/dotnet/runtime/blob/main/docs/coding-guidelines/framework-design-guidelines-digest.md) and [API Review Process](https://github.com/dotnet/runtime/blob/main/docs/project/api-review-process.md) to further investigate sample usages and investigate alternative designs and risks. cc: @davidfowl @eerhardt

Author:	maryamariyan
Assignees:	-
Labels:	`api-suggestion`, `area-Extensions-Logging`
Milestone:	-

[abatishchev]

@tarekgh any update on this, please?

[tarekgh]

We couldn't get into this yet because we are occupied with other high-priority tasks.