From cae5a4c70151a605c84634e240115f24fbb46d37 Mon Sep 17 00:00:00 2001
From: Lukasz Mierzwa <l.mierzwa@gmail.com>
Date: Wed, 8 Apr 2026 08:48:36 +0100
Subject: [PATCH] fix(api): fix JSON settings marshalling

Fixes #6696.
---
 CHANGELOG.md              |   4 ++
 cmd/karma/views_test.go   | 104 ++++++++++++++++++++++++++++++++++++++
 internal/config/models.go |  20 ++++----
 3 files changed, 118 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1908550ff..179639ea8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## v0.129
 
+### Fixed
+
+- Settings from the config file were not being pushed to the UI - #6696.
+
 ### Changed
 
 - Switched logging from zerolog to slog. Log output format has changed.
diff --git a/cmd/karma/views_test.go b/cmd/karma/views_test.go
index 45a9d2794..1ac6f1cc1 100644
--- a/cmd/karma/views_test.go
+++ b/cmd/karma/views_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"html/template"
@@ -3008,3 +3009,106 @@ func TestLabelSettings(t *testing.T) {
 		})
 	}
 }
+
+func TestIndexUIDefaultsJSON(t *testing.T) {
+	// Verifies that the index handler embeds a complete, valid JSON object
+	// in the <script id="defaults"> tag, with all UI config fields present
+	// and Refresh serialized as a nanosecond integer.
+	type uiDefaults struct {
+		Refresh              float64 `json:"Refresh"`
+		HideFiltersWhenIdle  bool    `json:"HideFiltersWhenIdle"`
+		ColorTitlebar        bool    `json:"ColorTitlebar"`
+		Theme                string  `json:"Theme"`
+		Animations           bool    `json:"Animations"`
+		MinimalGroupWidth    int     `json:"MinimalGroupWidth"`
+		AlertsPerGroup       int     `json:"AlertsPerGroup"`
+		CollapseGroups       string  `json:"CollapseGroups"`
+		MultiGridLabel       string  `json:"MultiGridLabel"`
+		MultiGridSortReverse bool    `json:"MultiGridSortReverse"`
+	}
+
+	type testCaseT struct {
+		// scenario describes the behaviour being tested
+		name                string
+		refresh             time.Duration
+		expectedRefreshNs   float64
+		alertsPerGroup      int
+		multiGridLabel      string
+		hideFiltersWhenIdle bool
+	}
+
+	testCases := []testCaseT{
+		{
+			// default config values produce correct JSON with 30s refresh
+			name:                "default 30s refresh",
+			refresh:             30 * time.Second,
+			expectedRefreshNs:   30000000000,
+			alertsPerGroup:      5,
+			multiGridLabel:      "",
+			hideFiltersWhenIdle: true,
+		},
+		{
+			// custom config values are all reflected in the embedded JSON
+			name:                "custom config values",
+			refresh:             45 * time.Second,
+			expectedRefreshNs:   45000000000,
+			alertsPerGroup:      15,
+			multiGridLabel:      "cluster",
+			hideFiltersWhenIdle: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockConfig(t.Setenv)
+			config.Config.UI.Refresh = tc.refresh
+			config.Config.UI.AlertsPerGroup = tc.alertsPerGroup
+			config.Config.UI.MultiGridLabel = tc.multiGridLabel
+			config.Config.UI.HideFiltersWhenIdle = tc.hideFiltersWhenIdle
+
+			r := testRouter()
+			setupRouter(r, nil)
+			mockCache()
+			req := httptest.NewRequest("GET", "/", nil)
+			resp := httptest.NewRecorder()
+			r.ServeHTTP(resp, req)
+			if resp.Code != http.StatusOK {
+				t.Fatalf("GET / returned status %d", resp.Code)
+			}
+
+			body := resp.Body.String()
+			re := regexp.MustCompile(`<script type="text/plain" id="defaults">\s*([A-Za-z0-9+/=]+)\s*</script>`)
+			matches := re.FindStringSubmatch(body)
+			if len(matches) < 2 {
+				t.Fatal("Could not find <script id=\"defaults\"> content in HTML response")
+			}
+
+			decoded, err := base64.StdEncoding.DecodeString(matches[1])
+			if err != nil {
+				t.Fatalf("Failed to base64-decode defaults: %v", err)
+			}
+
+			var got uiDefaults
+			if err := json.Unmarshal(decoded, &got); err != nil {
+				t.Fatalf("Failed to parse defaults JSON: %v\nraw: %s", err, string(decoded))
+			}
+
+			expected := uiDefaults{
+				Refresh:              tc.expectedRefreshNs,
+				HideFiltersWhenIdle:  tc.hideFiltersWhenIdle,
+				ColorTitlebar:        config.Config.UI.ColorTitlebar,
+				Theme:                config.Config.UI.Theme,
+				Animations:           config.Config.UI.Animations,
+				MinimalGroupWidth:    config.Config.UI.MinimalGroupWidth,
+				AlertsPerGroup:       tc.alertsPerGroup,
+				CollapseGroups:       config.Config.UI.CollapseGroups,
+				MultiGridLabel:       tc.multiGridLabel,
+				MultiGridSortReverse: config.Config.UI.MultiGridSortReverse,
+			}
+
+			if diff := cmp.Diff(expected, got); diff != "" {
+				t.Errorf("UI defaults mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
diff --git a/internal/config/models.go b/internal/config/models.go
index 079c75f4c..cde9eabb5 100644
--- a/internal/config/models.go
+++ b/internal/config/models.go
@@ -218,15 +218,15 @@ type configSchema struct {
 	} `yaml:"silenceForm" koanf:"silenceForm"`
 	// nolint: maligned
 	UI struct {
-		Refresh              time.Duration
-		HideFiltersWhenIdle  bool   `yaml:"hideFiltersWhenIdle" koanf:"hideFiltersWhenIdle"`
-		ColorTitlebar        bool   `yaml:"colorTitlebar" koanf:"colorTitlebar"`
-		Theme                string `yaml:"theme" koanf:"theme"`
-		Animations           bool   `yaml:"animations" koanf:"animations"`
-		MinimalGroupWidth    int    `yaml:"minimalGroupWidth" koanf:"minimalGroupWidth"`
-		AlertsPerGroup       int    `yaml:"alertsPerGroup" koanf:"alertsPerGroup"`
-		CollapseGroups       string `yaml:"collapseGroups" koanf:"collapseGroups"`
-		MultiGridLabel       string `yaml:"multiGridLabel" koanf:"multiGridLabel"`
-		MultiGridSortReverse bool   `yaml:"multiGridSortReverse" koanf:"multiGridSortReverse"`
+		Refresh              time.Duration `json:",format:nano"`
+		HideFiltersWhenIdle  bool          `yaml:"hideFiltersWhenIdle" koanf:"hideFiltersWhenIdle"`
+		ColorTitlebar        bool          `yaml:"colorTitlebar" koanf:"colorTitlebar"`
+		Theme                string        `yaml:"theme" koanf:"theme"`
+		Animations           bool          `yaml:"animations" koanf:"animations"`
+		MinimalGroupWidth    int           `yaml:"minimalGroupWidth" koanf:"minimalGroupWidth"`
+		AlertsPerGroup       int           `yaml:"alertsPerGroup" koanf:"alertsPerGroup"`
+		CollapseGroups       string        `yaml:"collapseGroups" koanf:"collapseGroups"`
+		MultiGridLabel       string        `yaml:"multiGridLabel" koanf:"multiGridLabel"`
+		MultiGridSortReverse bool          `yaml:"multiGridSortReverse" koanf:"multiGridSortReverse"`
 	}
 }