Add list of configs in app_settings configuration block

In terraform I declared a function_app resource:

resource "azurerm_windows_function_app" "func" {
  name                = local.func_app_name
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  
  service_plan_id = azurerm_service_plan.asp.id
  
  storage_account_name       = azurerm_storage_account.sa.name
  storage_account_access_key = azurerm_storage_account.sa.primary_access_key

  app_settings = {
    key1 = "value1"
    key2 = "value2"
  }

}

But i have a new requirements to add a new settings to app_settings.

New settings are placed in list because i iterate over it in another place in a code:

locals {
     publish_topics = {
       topicTest = "topic1",
       topicDev  = "topic2"
  }
}

How to add static values and values from a list from locals to app_settings config?

Add list of configs in app_settings configuration block:

Use below terraform code to achieve your requirement.

locals {
    publish_topics = {
       topic1 = "topic1"
       topic2 = "topic2"
  }
}
provider "azurerm" {
  features {}
}

data "azurerm_resource_group" "example" {
  name     = "xxxx"
}

resource "azurerm_service_plan" "example" {
  name                = "jahservice-plan"
  resource_group_name = azurerm_resource_group.example.name
  location            = azurerm_resource_group.example.location
  os_type             = "Windows"
  sku_name            = "Y1"
}
resource "azurerm_storage_account" "sa" {
  name                     = "xxx"
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "LRS"
}
resource "azurerm_windows_function_app" "func" {
  name                = "newfuncj"
  location            = data.azurerm_resource_group.rg.location
  resource_group_name = data.azurerm_resource_group.rg.name
  
  service_plan_id = azurerm_service_plan.example.id
  
  storage_account_name       = azurerm_storage_account.sa.name
  storage_account_access_key = azurerm_storage_account.sa.primary_access_key

  app_settings = merge(
    {
      key1 = "value1"
      key2 = "value2"
    },
    { for topic in local.publish_topics : 
          "topic:${topic}" => topic 
    }
  )
}

Refer here for relevant usage of locals block and retrieving it using foreach.

Update:

You can also use

for key, value in local.publish_topics : key => value as suggested by @michasaucer.