Allow using a custom asset path, overriding the embedded UI assets.

server/config/config.go

@@ -39,6 +39,7 @@ type (
 		TLS                 TLS    `yaml:"tls"`
 		Auth                Auth   `yaml:"auth"`
 		EnableUI            bool   `yaml:"enableUi"`
+		UIAssetPath         string `yaml:"uiAssetPath"`
 		EnableOpenAPI       bool   `yaml:"enableOpenApi"`
 		CORS                CORS   `yaml:"cors"`
 		DefaultNamespace    string `yaml:"defaultNamespace"`

server/route/ui.go

@@ -24,15 +24,14 @@ package route
 
 import (
 	"bytes"
-	"embed"
 	"io/fs"
 	"net/http"
 
 	"github.com/labstack/echo/v4"
 )
 
 // SetUIRoutes sets UI routes
-func SetUIRoutes(e *echo.Echo, indexHTML []byte, assets embed.FS) {
+func SetUIRoutes(e *echo.Echo, assets fs.FS) error {
 	assetsHandler := buildUIAssetsHandler(assets)
 	e.GET("/_app/*", assetsHandler)
 	e.GET("/css/*", assetsHandler)
@@ -44,18 +43,28 @@ func SetUIRoutes(e *echo.Echo, indexHTML []byte, assets embed.FS) {
 	e.GET("/logo*", assetsHandler)
 	e.GET("/Temporal_Logo_Animation.gif", assetsHandler)
 	e.GET("/site.webmanifest", assetsHandler)
-	e.GET("/*", buildUIIndexHandler(indexHTML))
+	indexHandler, err := buildUIIndexHandler(assets)
+	if err != nil {
+		return err
+	}
+
+	e.GET("/*", indexHandler)
+
+	return nil
 }
 
-func buildUIIndexHandler(indexHTML []byte) echo.HandlerFunc {
+func buildUIIndexHandler(assets fs.FS) (echo.HandlerFunc, error) {
+	indexHTML, err := fs.ReadFile(assets, "index.html")
+	if err != nil {
+		return nil, err
+	}
+
 	return func(c echo.Context) (err error) {
 		return c.Stream(200, "text/html", bytes.NewBuffer(indexHTML))
-	}
+	}, nil
 }
 
-func buildUIAssetsHandler(assets embed.FS) echo.HandlerFunc {
-	stream := fs.FS(assets)
-	stream, _ = fs.Sub(stream, "generated/ui")
-	handler := http.FileServer(http.FS(stream))
+func buildUIAssetsHandler(assets fs.FS) echo.HandlerFunc {
+	handler := http.FileServer(http.FS(assets))
 	return echo.WrapHandler(handler)
 }

server/server.go

@@ -25,7 +25,9 @@ package server
 import (
 	"embed"
 	"fmt"
+	"io/fs"
 	"net/http"
+	"os"
 
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
@@ -39,9 +41,6 @@ import (
 	"github.com/temporalio/ui-server/v2/server/server_options"
 )
 
-//go:embed generated/ui/index.html
-var uiHTML []byte
-
 //go:embed all:generated/ui
 var uiAssets embed.FS
 
@@ -112,7 +111,16 @@ func NewServer(opts ...server_options.ServerOption) *Server {
 		route.SetSwaggerUIRoutes(e, swaggeruiHTML, swaggeruiAssets)
 	}
 	if cfg.EnableUI {
-		route.SetUIRoutes(e, uiHTML, uiAssets)
+		var assets fs.FS
+		if cfg.UIAssetPath != "" {
+			assets = os.DirFS(cfg.UIAssetPath)
+		} else {
+			assets, err = fs.Sub(uiAssets, "generated/ui")
+			if err != nil {
+				panic(err)
+			}
+		}
+		route.SetUIRoutes(e, assets)
 	}
 
 	s := &Server{