add logic to automatically detect firmware irrespective of the Linux distribution

shared_modules/domain.tf

@@ -20,19 +20,15 @@ resource "libvirt_domain" "domain" {
 
   # ---- optional UEFI support ------------------------------------
   # Firmware – only add the string when a path is supplied
-  firmware = can(var.uefi_firmware) && length(var.uefi_firmware) > 0 ? var.uefi_firmware : null
+  firmware = local.detected_firmware
 
   # NVRAM block – dynamic block that is evaluated once per VM
   dynamic "nvram" {
-    # create the block once if a firmware path *and* a template were given
+    for_each = (local.detected_firmware != null && local.detected_nvram != null) ? [1] : []
-    for_each = (can(var.uefi_firmware) && length(var.uefi_firmware) > 0
-                && can(var.uefi_nvram_template) && length(var.uefi_nvram_template) > 0
-                ) ? [1] : []
 
     content {
-      # The NVRAM filename is per‑VM, but we can honour an optional suffix
       file     = "/var/lib/libvirt/qemu/nvram/${var.vm_name}-${count.index}${var.uefi_nvram_file_suffix}_VARS.fd"
-      template = var.uefi_nvram_template
+      template = local.detected_nvram
     }
   }
   # ----------------------------------------------------------------

shared_modules/variables.tf

@@ -105,23 +105,25 @@ variable "dns_local_only" {
   default     = false
 }
 
+# Improved UEFI variables with automatic detection
 variable "uefi_firmware" {
   description = <<EOT
-    Path to the UEFI firmware binary (OVMF_CODE.fd, QEMU_CODE.fd, …).
+    Enable UEFI support. Set to true to enable UEFI with auto-detected firmware,
-    Leave empty (or omit on the module call) to create a plain BIOS VM.
+    or provide a specific path to the firmware binary.
+    Set to false or omit to create a plain BIOS VM.
   EOT
   type        = string
-  default     = ""          # “BIOS only” when empty
+  default     = ""
 }
 
 variable "uefi_nvram_template" {
   description = <<EOT
     Path to an NV‑RAM template that backs the UEFI NVRAM.
     If you specify a template, the VM will get a writable NVRAM block.
-    Leave empty for a plain BIOS VM or if you don’t need UEFI NVRAM.
+    Leave empty for a plain BIOS VM or if you don't need UEFI NVRAM.
   EOT
   type        = string
-  default     = ""          # no NVRAM when empty
+  default     = ""
 }
 
 variable "uefi_nvram_file_suffix" {
@@ -135,7 +137,71 @@ variable "uefi_nvram_file_suffix" {
   default     = ""
 }
 
+
 # Computed variable for network domain (derived from vm_name)
 locals {
   computed_network_domain = var.network_domain != "" ? var.network_domain : "${var.vm_name}.local"
+  
+  # List of common UEFI firmware paths in order of preference  
+  uefi_firmware_paths = [
+    "/usr/share/edk2/ovmf/OVMF_CODE.4m.fd",
+    "/usr/share/edk2/x64/OVMF_CODE.4m.fd",
+    "/usr/share/OVMF/OVMF_CODE.4m.fd", 
+    "/usr/share/ovmf/OVMF_CODE.4m.fd",
+    "/usr/share/edk2/ovmf/OVMF_CODE.fd",
+    "/usr/share/edk2/x64/OVMF_CODE.fd",
+    "/usr/share/OVMF/OVMF_CODE.fd",
+    "/usr/share/ovmf/OVMF_CODE.fd"
+  ]
+  
+  uefi_nvram_paths = [
+    "/usr/share/edk2/ovmf/OVMF_VARS.4m.fd",
+    "/usr/share/edk2/x64/OVMF_VARS.4m.fd", 
+    "/usr/share/OVMF/OVMF_VARS.4m.fd",
+    "/usr/share/ovmf/OVMF_VARS.4m.fd",
+    "/usr/share/edk2/ovmf/OVMF_VARS.fd",
+    "/usr/share/edk2/x64/OVMF_VARS.fd",
+    "/usr/share/OVMF/OVMF_VARS.fd",
+    "/usr/share/ovmf/OVMF_VARS.fd"
+  ]
+  
+  # Helper function to find first existing file
+  find_first_existing = {
+    for path in local.uefi_firmware_paths : 
+    path => true if fileexists(path)
+  }
+  
+  # Function to get first available firmware path or null
+  detected_firmware = (
+    var.uefi_firmware == "true" || var.uefi_firmware == "" ? (
+      length(local.find_first_existing) > 0 ? 
+      keys(local.find_first_existing)[0] : 
+      null
+    ) : (
+      var.uefi_firmware != "" ? var.uefi_firmware : null
+    )
+  )
+  
+  # Same for NV-RAM template  
+  find_first_nvram = {
+    for path in local.uefi_nvram_paths : 
+    path => true if fileexists(path)
+  }
+  
+  detected_nvram = (
+    var.uefi_firmware == "true" || var.uefi_firmware == "" ? (
+      length(local.find_first_nvram) > 0 ? 
+      keys(local.find_first_nvram)[0] : 
+      null
+    ) : (
+      var.uefi_nvram_template != "" ? var.uefi_nvram_template : null
+    )
+  )
+  
+  # Validate that both firmware and NVRAM are provided together if one is specified
+  firmware_and_nvram_valid = (
+    (local.detected_firmware != null && local.detected_nvram == null) || 
+    (local.detected_firmware == null && local.detected_nvram == null) ||
+    (local.detected_firmware != null && local.detected_nvram != null)
+  )
 }