Set Retention Period for App Service logs in Azure WebApp Deployment

Question

I am deploying a Azure WebService (Linux Container) with az CLI and Biceps files. Below is an excerpt from my logging configuration.

resource appConfigLogs 'Microsoft.Web/sites/config@2021-02-01' = {
  name: 'logs'
  parent: app
  properties: {
    detailedErrorMessages: {
      enabled: true
    }
    failedRequestsTracing: {
      enabled: true
    }
    httpLogs: {
      fileSystem: {
        enabled: true
        retentionInDays: 7
        retentionInMb: 50
      }
    }
  }
}

To my understanding the setting "retentionInDays" corresponds to "Retention Period (Days)" which can be found in the Azure Portal in the WebApp Resource > "Monitoring" > "App Service logs".

When setting via Portal, the App Services Configuration gets updated with an Application setting called "WEBSEITE_HTTPLOGGING_RETENTION_DAYS" set to the respective value.

When setting via ARM Deplyment (see Biceps above), there is no Configuration value set. Is this a bug or do these two settings "retentionInDays" / "Retention Period (Days)" simply not correlate with each other?

Answer 1

When setting via ARM Deployment (see Biceps above), there is no Configuration value set. Is this a bug or do these two settings "retentionInDays" / "Retention Period (Days)" simply not correlate with each other?

This is not a bug."retentionInDays" / "Retention Period (Days)" are not two individual settings. In ARM template configuration in order to use retention period to store logs for a period of time we use this parameter retentionInDays same parameter will be displayed in the portal as RententionPeriod(Days)

We have written an ARM template & tested in our local environment which is working fine.This template will create web app, storage account, enabling app service logs & the application setting WEBSEITE_HTTPLOGGING_RETENTION_DAYS as well as shown below.

You can refer this blogpost for more information about configuring app server logs to a storage account using ARM template.