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Default console logger formatting in container images

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The default console formatter that's configured in aspnet containers has changed.

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 console output formatted similarly to the following:

txt 
{"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:\\source\\temp\\web50","State":{"Message":"Content root path: C:\\source\\temp\\web50","contentRoot":"C:\\source\\temp\\web50","{OriginalFormat}":"Content root path: {contentRoot}"}}

New behavior

Starting in .NET 6.0.5, aspnet container images have the Logging__Console__FormatterName environment variable unset by default. This results in simple, multiline, human-readable console output similar to the following:

txt 
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:\source\temp\web50

Version introduced

.NET 6.0.5 (May 2022 servicing)

Type of breaking change

This change can affect source compatibility.

Reason for change

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

If you want to continue using the JSON formatting, you can configure your container to use it by setting the Logging__Console__FormatterName environment variable value to Json.

Affected APIs

None.

See also