Fix the slowness of the Silence UI

ui/app/src/Utils/Api.elm

@@ -7,6 +7,22 @@ import Utils.Date
 import Utils.Types exposing (ApiData(..))
 
 
+map : (a -> b) -> ApiData a -> ApiData b
+map fn response =
+    case response of
+        Success value ->
+            Success (fn value)
+
+        Initial ->
+            Initial
+
+        Loading ->
+            Loading
+
+        Failure a ->
+            Failure a
+
+
 withDefault : a -> ApiData a -> a
 withDefault default response =
     case response of

ui/app/src/Views/AlertList/AlertView.elm

@@ -24,7 +24,10 @@ view labels maybeActiveId alert =
                 |> uncurry (++)
     in
         li
-            [ class "align-items-start list-group-item border-0 alert-list-item p-0 mb-4"
+            [ -- speedup rendering in Chrome, because list-group-item className
+              -- creates a new layer in the rendering engine
+              style [ ( "position", "static" ) ]
+            , class "align-items-start list-group-item border-0 p-0 mb-4"
             ]
             [ div
                 [ class "w-100 mb-2 d-flex align-items-start" ]

ui/app/src/Views/SilenceList/SilenceView.elm

@@ -13,14 +13,18 @@ import Utils.List
 import Utils.Types exposing (Matcher)
 import Utils.Views exposing (buttonLink)
 import Views.FilterBar.Types as FilterBarTypes
-import Views.SilenceForm.Types exposing (SilenceFormMsg(NewSilenceFromMatchers))
 import Views.SilenceList.Types exposing (SilenceListMsg(ConfirmDestroySilence, DestroySilence, FetchSilences, MsgForFilterBar))
 import Views.SilenceForm.Parsing exposing (newSilenceFromAlertLabels)
 
 
 view : Bool -> Silence -> Html Msg
 view showConfirmationDialog silence =
-    li [ class "align-items-start list-group-item border-0 alert-list-item p-0 mb-4" ]
+    li
+        [ -- speedup rendering in Chrome, because list-group-item className
+          -- creates a new layer in the rendering engine
+          style [ ( "position", "static" ) ]
+        , class "align-items-start list-group-item border-0 p-0 mb-4"
+        ]
         [ div [ class "w-100 mb-2 d-flex align-items-start" ]
             [ case silence.status.state of
                 Active ->

ui/app/src/Views/SilenceList/Types.elm

@@ -1,4 +1,4 @@
-module Views.SilenceList.Types exposing (Model, SilenceListMsg(..), initSilenceList)
+module Views.SilenceList.Types exposing (Model, SilenceTab, SilenceListMsg(..), initSilenceList)
 
 import Silences.Types exposing (Silence, State(Active), SilenceId)
 import Utils.Types exposing (ApiData(Initial))
@@ -14,8 +14,15 @@ type SilenceListMsg
     | SetTab State
 
 
+type alias SilenceTab =
+    { silences : List Silence
+    , tab : State
+    , count : Int
+    }
+
+
 type alias Model =
-    { silences : ApiData (List Silence)
+    { silences : ApiData (List SilenceTab)
     , filterBar : FilterBar.Model
     , tab : State
     , showConfirmationDialog : Maybe SilenceId

ui/app/src/Views/SilenceList/Updates.elm

@@ -2,17 +2,26 @@ module Views.SilenceList.Updates exposing (update, urlUpdate)
 
 import Navigation
 import Silences.Api as Api
+import Utils.Api as ApiData
 import Utils.Filter exposing (Filter, generateQueryString)
 import Utils.Types as Types exposing (ApiData(Failure, Loading, Success), Matchers, Time)
 import Views.FilterBar.Updates as FilterBar
-import Views.SilenceList.Types exposing (Model, SilenceListMsg(..))
+import Views.SilenceList.Types exposing (Model, SilenceTab, SilenceListMsg(..))
+import Silences.Types exposing (Silence, State(..))
 
 
 update : SilenceListMsg -> Model -> Filter -> String -> String -> ( Model, Cmd SilenceListMsg )
 update msg model filter basePath apiUrl =
     case msg of
-        SilencesFetch sils ->
-            ( { model | silences = sils }, Cmd.none )
+        SilencesFetch fetchedSilences ->
+            ( { model
+                | silences =
+                    ApiData.map
+                        (\silences -> List.map (groupSilencesByState silences) states)
+                        fetchedSilences
+              }
+            , Cmd.none
+            )
 
         FetchSilences ->
             ( { model
@@ -50,6 +59,28 @@ update msg model filter basePath apiUrl =
             ( { model | tab = tab }, Cmd.none )
 
 
+groupSilencesByState : List Silence -> State -> SilenceTab
+groupSilencesByState silences state =
+    let
+        silencesInTab =
+            filterSilencesByState state silences
+    in
+        { tab = state
+        , silences = silencesInTab
+        , count = List.length silencesInTab
+        }
+
+
+states : List State
+states =
+    [ Active, Pending, Expired ]
+
+
+filterSilencesByState : State -> List Silence -> List Silence
+filterSilencesByState state =
+    List.filter (.status >> .state >> (==) state)
+
+
 urlUpdate : Maybe String -> ( SilenceListMsg, Filter )
 urlUpdate maybeString =
     ( FetchSilences, updateFilter maybeString )

ui/app/src/Views/SilenceList/Views.elm

@@ -4,13 +4,14 @@ import Html exposing (..)
 import Html.Attributes exposing (..)
 import Silences.Types exposing (Silence, State(..), stateToString, SilenceId)
 import Types exposing (Msg(MsgForSilenceList, Noop, UpdateFilter))
-import Utils.Api exposing (withDefault)
 import Utils.String as StringUtils
 import Utils.Types exposing (ApiData(..), Matcher)
 import Utils.Views exposing (buttonLink, checkbox, error, formField, formInput, iconButtonMsg, loading, textField)
 import Views.FilterBar.Views as FilterBar
 import Views.SilenceList.SilenceView
-import Views.SilenceList.Types exposing (Model, SilenceListMsg(..))
+import Views.SilenceList.Types exposing (Model, SilenceListMsg(..), SilenceTab)
+import Html.Lazy exposing (lazy, lazy2, lazy3)
+import Html.Keyed
 
 
 view : Model -> Html Msg
@@ -20,49 +21,69 @@ view { filterBar, tab, silences, showConfirmationDialog } =
             [ label [ class "mb-2", for "filter-bar-matcher" ] [ text "Filter" ]
             , Html.map (MsgForFilterBar >> MsgForSilenceList) (FilterBar.view filterBar)
             ]
-        , ul [ class "nav nav-tabs mb-4" ]
-            (List.map (tabView tab) (groupSilencesByState (withDefault [] silences)))
-        , case silences of
-            Success sils ->
-                silencesView showConfirmationDialog (filterSilencesByState tab sils)
+        , lazy2 tabsView tab silences
+        , lazy3 silencesView showConfirmationDialog tab silences
+        ]
 
-            Failure msg ->
-                error msg
 
-            _ ->
-                loading
-        ]
+tabsView : State -> ApiData (List SilenceTab) -> Html Msg
+tabsView currentTab tabs =
+    case tabs of
+        Success silencesTabs ->
+            List.map (\{ tab, count } -> tabView currentTab count tab) silencesTabs
+                |> ul [ class "nav nav-tabs mb-4" ]
+
+        _ ->
+            List.map (tabView currentTab 0) states
+                |> ul [ class "nav nav-tabs mb-4" ]
 
 
-tabView : State -> ( State, List a ) -> Html Msg
-tabView currentState ( state, silences ) =
-    Utils.Views.tab state currentState (SetTab >> MsgForSilenceList) <|
-        case List.length silences of
+tabView : State -> Int -> State -> Html Msg
+tabView currentTab count tab =
+    Utils.Views.tab tab currentTab (SetTab >> MsgForSilenceList) <|
+        case count of
             0 ->
-                [ text (StringUtils.capitalizeFirst (stateToString state)) ]
+                [ text (StringUtils.capitalizeFirst (stateToString tab)) ]
 
             n ->
-                [ text (StringUtils.capitalizeFirst (stateToString state))
+                [ text (StringUtils.capitalizeFirst (stateToString tab))
                 , span
                     [ class "badge badge-pillow badge-default align-text-top ml-2" ]
                     [ text (toString n) ]
                 ]
 
 
-silencesView : Maybe SilenceId -> List Silence -> Html Msg
-silencesView showConfirmationDialog silences =
-    if List.isEmpty silences then
-        Utils.Views.error "No silences found"
-    else
-        ul [ class "list-group" ]
-            (List.map
-                (\silence ->
-                    Views.SilenceList.SilenceView.view
-                        (showConfirmationDialog == Just silence.id)
-                        silence
-                )
-                silences
-            )
+silencesView : Maybe SilenceId -> State -> ApiData (List SilenceTab) -> Html Msg
+silencesView showConfirmationDialog tab silencesTab =
+    case silencesTab of
+        Success tabs ->
+            tabs
+                |> List.filter (.tab >> (==) tab)
+                |> List.head
+                |> Maybe.map .silences
+                |> Maybe.withDefault []
+                |> (\silences ->
+                        if List.isEmpty silences then
+                            Utils.Views.error "No silences found"
+                        else
+                            Html.Keyed.ul [ class "list-group" ]
+                                (List.map
+                                    (\silence ->
+                                        ( silence.id
+                                        , Views.SilenceList.SilenceView.view
+                                            (showConfirmationDialog == Just silence.id)
+                                            silence
+                                        )
+                                    )
+                                    silences
+                                )
+                   )
+
+        Failure msg ->
+            error msg
+
+        _ ->
+            loading
 
 
 groupSilencesByState : List Silence -> List ( State, List Silence )