How to set custom app settings in Microsoft.Web/sites web app?

[MJ Rathbun (bert2)]

We're struggling with the usage of the Microsoft.Web/sites module. In particular we can't find a way to provision it with our custom app settings. This is how we are trying to achieve this:

module myWebApp './Microsoft.Web/sites/deploy.bicep' = {
    // ...
    params: {
        // ...
        siteConfig: {
            // ...
            appSettings: [
                {
                    name: 'MyCustomSetting'
                    value: 'MyCustomValue'
                }
            ]
        }
    }
}

The deployment works without errors, but the web app doesn't get this setting. So is this the correct way? Unfortunately we can't find any usage examples.

[MJ Rathbun (bert2)]

We found out that the Microsoft.Web/sites module seems to overwrite anything that is passed as part of the siteConfig parameter. The way we understand it, the child module Microsoft.Web/sites/config (internally used by the Microsoft.Web/sites module) seems to create a new site configuration without incorporating the values from siteConfig.

Is this intended behavior?

[Alexander Sehr (AlexanderSehr)]

Hey MJ Rathbun (@bert2), excuse the late reply. Discussions are not that commonly used in this repository. It seems the Sites module requires some major overhaul to properly apply the AppSettings (ref #1146).
The properties object for the config is 'complicated' to say the least.
What you tried above does not work because the Sites module does not pass any unknown parameters (in this case appSettings) down to the confirm child-template:

module app_appsettings 'config/deploy.bicep' = {
  name: '${uniqueString(deployment().name, location)}-Site-Config'
  params: {
    name: 'appsettings'
    appName: app.name
    storageAccountId: !empty(storageAccountId) ? storageAccountId : ''
    appInsightId: !empty(appInsightId) ? appInsightId : !empty(appInsightObject) ? appInsight.outputs.resourceId : ''
    functionsWorkerRuntime: !empty(functionsWorkerRuntime) ? functionsWorkerRuntime : ''
    functionsExtensionVersion: !empty(functionsExtensionVersion) ? functionsExtensionVersion : '~3'
    ... <- no other parameters
  }
}

We have discussed this issue recently and somebody should pick the issue up soon. I'll be curious to see the result.

[Alexander Sehr (AlexanderSehr)]

I implemented an update in #1258 that should enable you to apply your own custom app settings

[Alexander Sehr (AlexanderSehr)]

MJ Rathbun (@bert2) Please check out the latest module version. It was reworked and supports CustomAppSettings (aside from a couple other features)