MVD CP-52334 multi-version driver API/CLI - incremental update

When scanning a host for drivers, don't remove and re-create them but
instead update an entry if it already exists.

Signed-off-by: Christian Lindig <[email protected]>

ocaml/xapi/xapi_host_driver.ml

@@ -58,6 +58,34 @@ module Variant = struct
     debug "Destroying driver variant %s" (Ref.string_of self) ;
     Db.Driver_variant.destroy ~__context ~self
 
+  (** create' is like create but updates an exisiting entry if it
+      exists. This avoids entries becoming stale *)
+  let create' ~__context ~name ~version ~driver ~hw_present ~priority
+      ~dev_status =
+    let open Xapi_database.Db_filter_types in
+    (* driver and name identify a variant uniquely *)
+    let driver' = Eq (Field "driver", Literal (Ref.string_of driver)) in
+    let name' = Eq (Field "name", Literal name) in
+    let expr = And (driver', name') in
+    match Db.Driver_variant.get_refs_where ~__context ~expr with
+    | [] ->
+        create ~__context ~name ~version ~driver ~hw_present ~priority
+          ~dev_status
+    | [self] ->
+        debug "%s: updating existing entry for variant %s" __FUNCTION__ name ;
+        Db.Driver_variant.set_version ~__context ~self ~value:version ;
+        Db.Driver_variant.set_priority ~__context ~self ~value:priority ;
+        Db.Driver_variant.set_status ~__context ~self ~value:dev_status ;
+        Db.Driver_variant.set_hardware_present ~__context ~self
+          ~value:hw_present ;
+        self
+    | variants ->
+        warn "%s: multiple entries for %s found; recreating one" __FUNCTION__
+          name ;
+        variants |> List.iter (fun self -> destroy ~__context ~self) ;
+        create ~__context ~name ~version ~driver ~hw_present ~priority
+          ~dev_status
+
   let select ~__context ~self =
     debug "%s: %s" __FUNCTION__ (Ref.string_of self) ;
     let drv = Db.Driver_variant.get_driver ~__context ~self in
@@ -86,6 +114,37 @@ let destroy ~__context ~self =
   variants |> List.iter (fun self -> Variant.destroy ~__context ~self) ;
   Db.Host_driver.destroy ~__context ~self
 
+(** create' is like create except it checks if an entry exists and
+    modifies it. This avoids ref/UUIDs becoming stale *)
+let create' ~__context ~host ~name ~friendly_name ~_type ~description ~info:inf
+    ~active_variant ~selected_variant =
+  let null = Ref.null in
+  let open Xapi_database.Db_filter_types in
+  let host' = Eq (Field "host", Literal (Ref.string_of host)) in
+  let name' = Eq (Field "name", Literal name) in
+  let expr = And (host', name') in
+  match Db.Host_driver.get_refs_where ~__context ~expr with
+  | [] ->
+      (* no such entry exists - create it *)
+      create ~__context ~host ~name ~friendly_name ~info:inf
+        ~active_variant:null ~selected_variant:null ~description ~_type
+  | [self] ->
+      (* one existing entry - update it *)
+      info "%s: updating host driver %s" __FUNCTION__ name ;
+      Db.Host_driver.set_friendly_name ~__context ~self ~value:name ;
+      Db.Host_driver.set_info ~__context ~self ~value:inf ;
+      Db.Host_driver.set_active_variant ~__context ~self ~value:null ;
+      Db.Host_driver.set_selected_variant ~__context ~self ~value:null ;
+      Db.Host_driver.set_description ~__context ~self ~value:description ;
+      Db.Host_driver.set_type ~__context ~self ~value:_type ;
+      self
+  | drivers ->
+      warn "%s: more than one entry for driver %s; destroying them" __FUNCTION__
+        name ;
+      drivers |> List.iter (fun self -> destroy ~__context ~self) ;
+      create ~__context ~host ~name ~friendly_name ~info:inf
+        ~active_variant:null ~selected_variant:null ~description ~_type
+
 (** Runs on the host where the driver is installed *)
 let select ~__context ~self ~variant =
   let drv = Ref.string_of self in
@@ -126,19 +185,18 @@ let reset ~__context ~host =
 let scan ~__context ~host =
   T.Mock.install () ;
   let null = Ref.null in
-  reset ~__context ~host ;
   drivertool ["list"]
   |> T.parse
   |> List.iter @@ fun (_name, driver) ->
      let driver_ref =
-       create ~__context ~host ~name:driver.T.name ~friendly_name:driver.T.name
+       create' ~__context ~host ~name:driver.T.name ~friendly_name:driver.T.name
          ~info:driver.T.info ~active_variant:null ~selected_variant:null
          ~description:driver.T.descr ~_type:driver.T.ty
      in
      driver.T.variants
      |> List.iter @@ fun (name, v) ->
         let var_ref =
-          Variant.create ~__context ~name ~version:v.T.version
+          Variant.create' ~__context ~name ~version:v.T.version
             ~driver:driver_ref ~hw_present:v.T.hw_present ~priority:v.T.priority
             ~dev_status:v.T.dev_status
         in