[Breaking change]: Revert the Console Formatter Default in .NET 6 Containers

[mthalman]

Description

The breaking change will occur in .NET 6.0.5 (May 2022 servicing) and is related to the default console formatter configured in aspnet containers. See dotnet/dotnet-docker#3706 for details.

Version

Other (please put exact version in description textbox)

Previous behavior

In previous servicing releases of .NET 6, aspnet container images were configured with the Logging__Console__FormatterName environment variable set to Json. This resulted in the console output similar to the following:

{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Now listening on: http://localhost:7000/","State":{"Message":"Now listening on: http://localhost:7000/","address":"http://localhost:7000/","{OriginalFormat}":"Now listening on: {address}"}}
{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Now listening on: http://localhost:7001/","State":{"Message":"Now listening on: http://localhost:7001/","address":"http://localhost:7001/","{OriginalFormat}":"Now listening on: {address}"}}
{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Now listening on: http://localhost:7002/","State":{"Message":"Now listening on: http://localhost:7002/","address":"http://localhost:7002/","{OriginalFormat}":"Now listening on: {address}"}}
{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Application started. Press Ctrl\u002BC to shut down.","State":{"Message":"Application started. Press Ctrl\u002BC to shut down.","{OriginalFormat}":"Application started. Press Ctrl\u002BC to shut down."}}
{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Hosting environment: Development","State":{"Message":"Hosting environment: Development","envName":"Development","{OriginalFormat}":"Hosting environment: {envName}"}}
{"EventId":0,"LogLevel":"Information","Category":"Microsoft.Hosting.Lifetime","Message":"Content root path: C:\\Users\\shirh\\source\\temp\\web50","State":{"Message":"Content root path: C:\\Users\\shirh\\source\\temp\\web50","contentRoot":"C:\\Users\\shirh\\source\\temp\\web50","{OriginalFormat}":"Content root path: {contentRoot}"}}

New behavior

Starting in .NET 6.0.5, aspnet containers will revert the Logging__Console__FormatterName change and leave it unset, resulting in output similar to the following:

warn: Microsoft.AspNetCore.Server.HttpSys.MessagePump[37]
      Overriding address(es) ''. Binding to endpoints added to UrlPrefixes instead.
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: http://localhost:7000/
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: http://localhost:7001/
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: http://localhost:7002/
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
      Content root path: C:\Users\shirh\source\temp\web50

Type of breaking change

• Binary incompatible: Existing binaries may encounter a breaking change in behavior, such as failure to load/execute or different run-time behavior.
• Source incompatible: Source code may encounter a breaking change in behavior when targeting the new runtime/component/SDK, such as compile errors or different run-time behavior.

Reason for change

When the change to use JSON formatting was made in the .NET 6 GA release, this broken many scenarios that relied on the original simple formatting as described in dotnet/dotnet-docker#2725.

Recommended action

If users do not want this change and want to continue using the JSON formatting, they can configure their container to use this by setting the Logging__Console__FormatterName environment variable to Json.

Feature area

Other (please put exact area in description textbox)

Affected APIs

No response

[gewarren]

Related to #27906.