Bug report- azurerm_logic_app_standard virtual_network_subnet_id is always reset when connecting to virtual network using azurerm_app_service_virtual_network_swift_connection

[arne21a]

Is there an existing issue for this?

• I have searched the existing issues

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Version of the module you are using

5.7.11

Rover Version

rover:1.4.6-2305.1807

Terraform Version

v1.4.6 on linux_arm64

AzureRM Provider Version

3.75.0

Affected Resource(s)/Data Source(s)

azurerm_logic_app_standard, azurerm_app_service_virtual_network_swift_connection

Terraform Configuration Files

logic_app_standard = {
  las1 = {
    name                 = "logicapp2"
    resource_group_key   = "la_test"
    app_service_plan_key = "asp1"
    storage_account_key  = "sa1"
    version              = "~4"
    # Required for virtual network integration
    vnet_integration = {
      vnet_key   = "vnet"
      subnet_key = "la_test_subnet"
      lz_key     = "sandbox_level3"
      # subnet_id = ""
    }
  }
}

Expected Behaviour

A azurerm_logic_app_standard and a azurerm_app_service_virtual_network_swift_connection is created. The azurerm_logic_app_standard recognizes the external configuration and does not overwrite it.

Actual Behaviour

A azurerm_logic_app_standard and a azurerm_app_service_virtual_network_swift_connection are created. The azurerm_app_service_virtual_network_swift_connection sets the subnet_id attribute of the azurerm_logic_app_standard which does not recognizes the external configuration and tries to overwrite it.
This issue is discussed in this issue with close to 50 upvotes:
hashicorp/terraform-provider-azurerm#17930

The issue mentions two possible workarounds:

1. Lifecycle policy. Thats not an option with CAF
2. Not using the azurerm_app_service_virtual_network_swift_connection. Instead use the subnet_id attribute of azurerm_logic_app_standard.

Option two works for us, but the change from azurerm_app_service_virtual_network_swift_connection to the subnet_id attribute comes with a downtime. Therfore i would consider this workaround a "breaking change" to CAF.

I will provide our solution as a PR, it is on the maintainers to decide if thats a good idea for everyone.

Steps to Reproduce

No response

Important Factoids

No response

References

No response