[Dashboard] Do not cache index.html to prevent issues where Dashboard…

… doesn't load when the ray version is upgraded. (#42670)

Do not cache index.html to prevent issues where Dashboard doesn't load when the ray version is upgraded.
Explictly sets a long cache time for static files to improve performance for files we know will not change

Signed-off-by: Alan Guo <[email protected]>

dashboard/http_server_head.py

@@ -109,11 +109,13 @@ async def get_index(self, req) -> aiohttp.web.FileResponse:
  "This error message is harmless and can be ignored. "
  f"Error: {e}"
  )
- return aiohttp.web.FileResponse(
+ resp = aiohttp.web.FileResponse(
  os.path.join(
  os.path.dirname(os.path.abspath(__file__)), "client/build/index.html"
  )
  )
+ resp.headers["Cache-Control"] = "no-cache"
+ return resp
 
  @routes.get("/favicon.ico")
  async def get_favicon(self, req) -> aiohttp.web.FileResponse:
@@ -190,6 +192,14 @@ async def metrics_middleware(self, request, handler):
  except Exception as e:
  logger.exception(f"Error emitting api metrics: {e}")
 
+ @aiohttp.web.middleware
+ async def cache_control_static_middleware(self, request, handler):
+ if request.path.startswith("/static"):
+ response = await handler(request)
+ response.headers["Cache-Control"] = "max-age=31536000"
+ return response
+ return await handler(request)
+
  async def run(self, modules):
  # Bind http routes of each module.
  for c in modules:
@@ -203,6 +213,7 @@ async def run(self, modules):
  self.metrics_middleware,
  self.path_clean_middleware,
  self.browsers_no_post_put_middleware,
+ self.cache_control_static_middleware,
  ],
  )
  app.add_routes(routes=routes.bound_routes())