Add Build.get_previous database lookup

db/builder_db.ml

@@ -382,6 +382,21 @@ module Build = struct
          LIMIT 1
       |}
 
+  let get_previous =
+    Caqti_request.find_opt
+      id
+      Caqti_type.(tup2 id Meta.t)
+      {| SELECT b.id,
+           b.uuid, b.start_d, b.start_ps, b.finish_d, b.finish_ps,
+           b.result_kind, b.result_code, b.result_msg,
+           b.main_binary, b.job
+         FROM build b, build b0
+         WHERE b0.id = ? AND b0.job = b.job AND
+           (b0.start_d > b.start_d OR b0.start_d = b.start_d AND b0.start_ps > b.start_ps)
+         ORDER BY b.start_d DESC, b.start_ps DESC
+         LIMIT 1
+      |}
+
   let add =
     Caqti_request.exec
       t

db/builder_db.mli

@@ -146,6 +146,9 @@ sig
   val get_latest :
     (id, id * Meta.t * file option, [< `Many | `One | `Zero > `One `Zero ])
       Caqti_request.t
+  val get_previous :
+    (id, id * Meta.t, [< `Many | `One | `Zero > `One `Zero ])
+      Caqti_request.t
   val add : (t, unit, [< `Many | `One | `Zero > `Zero ]) Caqti_request.t
   val get_by_hash :
     (Cstruct.t, string * t, [< `Many | `One | `Zero > `One `Zero]) Caqti_request.t

test/builder_db.ml

@@ -233,6 +233,22 @@ let test_build_get_latest (module Db : CONN) =
   Alcotest.(check (option Testable.file)) "same main binary" main_binary' (Some main_binary);
   Alcotest.(check Testable.uuid) "same uuid" meta.uuid uuid'
 
+let test_build_get_previous (module Db : CONN) =
+  add_second_build (module Db) >>= fun () ->
+  Db.find_opt Builder_db.Build.get_by_uuid uuid'
+  >>| get_opt "no build" >>= fun (id, _build) ->
+  Db.find_opt Builder_db.Build.get_previous id
+  >>| get_opt "no previous build" >>| fun (_id, meta) ->
+  Alcotest.(check Testable.uuid) "same uuid" meta.uuid uuid
+
+let test_build_get_previous_none (module Db : CONN) =
+  Db.find_opt Builder_db.Build.get_by_uuid uuid
+  >>| get_opt "no build" >>= fun (id, _build) ->
+  Db.find_opt Builder_db.Build.get_previous id >>| function
+  | None -> ()
+  | Some (_id, meta) ->
+    Alcotest.failf "Got unexpected result %a" Uuidm.pp meta.uuid
+
 let test_build_get_by_hash (module Db : CONN) =
   add_second_build (module Db) >>= fun () ->
   Db.find_opt Builder_db.Build.get_by_hash main_binary.sha256
@@ -293,6 +309,8 @@ let () =
       test_case "One build (meta data)" `Quick (with_build_db test_build_get_all_meta);
       test_case "Get latest build" `Quick (with_build_db test_build_get_latest);
       test_case "Get build by hash" `Quick (with_build_db test_build_get_by_hash);
+      test_case "Get previous build" `Quick (with_build_db test_build_get_previous);
+      test_case "Get previous build when first" `Quick (with_build_db test_build_get_previous_none);
     ];
     "build-artifact", [
       test_case "Get all by build" `Quick (with_build_db test_artifact_get_all_by_build);