How to stop info and debug messages from Azure function host

Question

The Azure function infrastructure spits out a lot of info and debug messages which I want to filter out. Log level filtering seems to be specific to Application Insights which if disabled for my function app.

e.g.

Starting JobHost

Starting Host (HostId ...

FUNCTIONS_WORKER_RUNTIME value: 'dotnet-isolated'

Adding Function descriptor provider for language dotnet-isolated.

...

Poll for function ...

Function 'xxxx' will wait 335.6767 ms before polling queue ...

Executing HTTP request: { "requestId": "623275a0-e13e-41ff-9dc0-e6020fa01538", "method": "GET", "userAgent": "HealthCheck/1.0...

...

I tried the following in host.json.

"logging": {

    "logLevel": {

        "default": "None",

        "Function": "Error",

        "Function.Myfunction": "Error",

        "Function.Myfunction.User": "Error",

        "Azure.Core": "Warning",

        "Azure.Storage.Blobs": "Error",

        "Azure.Storage.Queues": "Error",

        "Host.Aggregator": "Error",

        "Host.Results": "Error"

    }

},

The function uses Serilog. Tried the following settings.

"Serilog": {

    "MinimumLevel": {

        "Default": "Error",

        "Override": {

            "Microsoft": "Error",

            "System": "Error",

            "MicroElements": "Error",

            "Microsoft.EntityFrameworkCore": "Error",

            "Zenfolio.Common.EntityFramework": "Error",

            "Azure": "Warning",

            "Azure.Core": "Warning",

            "Azure.Storage.Blobs": "Warning",

            "Azure.Storage.Files": "Warning",

            "Azure.Storage.Queues": "Warning",

            "Microsoft.Azure.Functions.Worker.Extensions.Storage": "Warning",

            "Microsoft.Azure.Functions.Worker": "Warning",

            "Microsoft.Extensions.Azure": "Warning",

            "Microsoft.Extensions.Configuration": "Warning",

            "Microsoft.Azure.WebJobs.Extensions.Storage.Blobs": "Warning",

            "Microsoft.Azure.WebJobs.Extensions.Storage": "Warning"

        }

    },

    "WriteTo": []

},

None of the log level settings in host.json and Serilog work.

Answer 1

Hello @Stanley Yau

Here are a few suggestions that might help:

1. Set a higher log level: The execution logs you want to get rid of are generated by the function runtime. You can set a higher log level to filter information and keep your self-defined info. For example, in your host.json, you can set the log level for Function and Function.MyFunctionName.User to Error
2. Use Azure portal to override: After deploying in Azure, if you want to override logging, you can add the AzureFunctionsJobHost__path__to__setting setting in Application Settings in the function Configuration.
3. Disable specific function logging: In host.json, while logging your function telemetry information, you can use the log level None to disable the specified category log
4. Disable built-in logging: If you want to disable built-in logging, you can delete the AzureWebJobsDashboard app setting

Please note that these changes might affect your custom information logs.

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