[Libguestfs] [PATCH 07/10] dib: add appliance check hook in Output_format

[Pino Toscano]

Add a new hook for Output_format's to check for prerequisites on the
appliance (which can be done only when the appliance is run).
---
 dib/dib.ml            |  2 ++
 dib/output_format.ml  | 15 +++++++++++++++
 dib/output_format.mli |  9 +++++++++
 3 files changed, 26 insertions(+)

diff --git a/dib/dib.ml b/dib/dib.ml
index b578750..df83ba1 100644
--- a/dib/dib.ml
+++ b/dib/dib.ml
@@ -703,6 +703,8 @@ let main () =
 
     g#launch ();
 
+    Output_format.check_formats_appliance_prerequisites cmdline.formats g;
+
     (* Prepare the /aux partition. *)
     g#mkfs "ext2" "/dev/sdb";
     g#mount "/dev/sdb" "/";
diff --git a/dib/output_format.ml b/dib/output_format.ml
index f311b8d..851cefc 100644
--- a/dib/output_format.ml
+++ b/dib/output_format.ml
@@ -27,6 +27,7 @@ type format = {
   extra_args : extra_arg list;
   output_to_file : bool;
   check_prerequisites : (unit -> unit) option;
+  check_appliance_prerequisites : (Guestfs.guestfs -> unit) option;
   run_on_filesystem : (Guestfs.guestfs -> string -> string -> unit) option;
   run_on_file : (string -> (string * string) -> string -> unit) option;
 }
@@ -39,6 +40,7 @@ let defaults = {
   extra_args = [];
   output_to_file = true;
   check_prerequisites = None;
+  check_appliance_prerequisites = None;
   run_on_filesystem = None;
   run_on_file = None;
 }
@@ -129,6 +131,19 @@ let check_formats_prerequisites ~formats =
     | { check_prerequisites = None } -> ()
   ) formats
 
+let check_formats_appliance_prerequisites ~formats g =
+  assert !baked;
+
+  (* Run the formats in alphabetical, rather than random order. *)
+  let formats = List.sort compare_formats (FormatSet.elements formats) in
+
+  List.iter (
+    function
+    | { check_appliance_prerequisites = Some fn } ->
+      fn g
+    | { check_appliance_prerequisites = None } -> ()
+  ) formats
+
 let run_formats_on_filesystem ~formats g image_name tmpdir =
   assert !baked;
 
diff --git a/dib/output_format.mli b/dib/output_format.mli
index e935f6f..76683ad 100644
--- a/dib/output_format.mli
+++ b/dib/output_format.mli
@@ -44,6 +44,11 @@ type format = {
       to check whether the requirements for this format (available
       tools, values for command line arguments, etc) are fulfilled. *)
 
+  check_appliance_prerequisites : (Guestfs.guestfs -> unit) option;
+  (** The function which is called after the appliance start to check
+      whether the requirements in the appliance for this format
+      (available features, filesystems, etc) are fulfilled. *)
+
   run_on_filesystem : (Guestfs.guestfs -> string -> string -> unit) option;
   (** The function which is called to perform the export while the
       guest is mounted.
@@ -108,6 +113,10 @@ val set_cardinal : set -> int
 val check_formats_prerequisites : formats:set -> unit
 (** Check the prerequisites in all the formats listed in the [formats] set. *)
 
+val check_formats_appliance_prerequisites : formats:set -> Guestfs.guestfs -> unit
+(** Check the appliance prerequisites in all the formats listed in the
+    [formats] set. *)
+
 val run_formats_on_filesystem : formats:set -> Guestfs.guestfs -> string -> string -> unit
 (** Run the filesystem-based export for all the formats listed in the
     [formats] set. *)
-- 
2.9.3