prototype: add instance default sidebar dock feature toggle and client init script

pkg/api/frontend_settings.go

@@ -0,0 +1,27 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+// Note: This is a minimal example showing how to add feature toggles to the boot payload.
+// Integrate with Grafana's actual frontend boot data code path (where the server renders JSON into the page).
+func frontendSettingsHandler(w http.ResponseWriter, r *http.Request) {
+	// Example existing boot data:
+	boot := map[string]interface{}{
+		"settings": map[string]interface{}{},
+	}
+
+	// Add our feature toggle into the front-end settings payload.
+	settings := boot["settings"].(map[string]interface{})
+
+	settings["featureToggles"] = map[string]interface{}{
+		"default_sidebar_docked": setting.FeatureToggleConfig.DefaultSidebarDocked,
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	_ = json.NewEncoder(w).Encode(boot)
+}

pkg/setting/feature_toggles.go

@@ -0,0 +1,21 @@
+package setting
+
+import (
+	"gopkg.in/ini.v1"
+)
+
+// FeatureToggles holds lightweight feature flags that can be set via grafana.ini
+type FeatureToggles struct {
+	// DefaultSidebarDocked determines the default state of the left navigation when no per-browser
+	// preference exists in localStorage (grafana.navigation.docked).
+	DefaultSidebarDocked bool `json:"default_sidebar_docked"`
+}
+
+var FeatureToggleConfig = &FeatureToggles{DefaultSidebarDocked: true}
+
+// loadFeatureToggles reads [feature_toggles] section from the provided INI file.
+// This is a minimal helper; integrate it into your existing settings loader.
+func loadFeatureToggles(cfg *ini.File) {
+	sec := cfg.Section("feature_toggles")
+	FeatureToggleConfig.DefaultSidebarDocked = sec.Key("default_sidebar_docked").MustBool(true)
+}

public/scripts/set-default-sidebar.js

@@ -0,0 +1,43 @@
+// This script runs very early (before frontend bundles) so we cannot import @grafana/data here.
+// Disable the lint rule that forbids direct localStorage usage for this file.
+/* eslint-disable no-restricted-syntax */
+
+(function () {
+  try {
+    let key = 'grafana.navigation.docked';
+
+    // If already set (user choice exists), do nothing.
+    if (localStorage.getItem(key) !== null) {
+      return;
+    }
+
+    // Try the server-provided boot data (common Grafana pattern)
+    let serverDefault;
+    if (
+      typeof window !== 'undefined' &&
+      window.grafanaBootData &&
+      window.grafanaBootData.settings &&
+      window.grafanaBootData.settings.featureToggles
+    ) {
+      serverDefault = window.grafanaBootData.settings.featureToggles.default_sidebar_docked;
+    }
+
+    // Fallback: a page-global var you can set for quick testing in index.html
+    let globalDefault = typeof window !== 'undefined' ? window.__defaultSidebarDocked : undefined;
+
+    // If neither is provided, leave the existing Grafana default (true/docked).
+    let val =
+      typeof serverDefault !== 'undefined'
+        ? serverDefault
+        : typeof globalDefault !== 'undefined'
+          ? globalDefault
+          : undefined;
+
+    if (typeof val !== 'undefined') {
+      // localStorage stores strings; Grafana historically uses 'true'/'false' for this key.
+      localStorage.setItem(key, val ? 'true' : 'false');
+    }
+  } catch (e) {
+    // Keep page stable if something goes wrong
+  }
+})();

public/views/index.html

@@ -267,6 +267,13 @@
 
     <div id="reactRoot"></div>
 
+    <!-- Insert this just before the inline script that assigns window.grafanaBootData -->
+    <script>
+      // Optional quick local override for testing without changing server code:
+      // window.__defaultSidebarDocked = false;
+    </script>
+    <script src="/public/scripts/set-default-sidebar.js"></script>
+
     <script nonce="[[.Nonce]]">
       window.grafanaBootData = {
         user: [[.User]],