import ( "github.com/grafana/grafana/pkg/middleware" "github.com/grafana/grafana/pkg/util" ) func myHandler(ctx *middleware.Context, w http.ResponseWriter, r *http.Request) { // some code that may cause an error if err != nil { ctx.JsonApiErr(w, err.Error(), http.StatusInternalServerError) return } // code that runs if there was no error respData := util.DummyData() ctx.JsonOK(w, respData) }In this example, `JsonApiErr` is used to return an error message in JSON format if an error occurs in the handler function. The response status code is also set to 500. The `JsonOK` function in the `Context` package can be used to return a successful response in JSON format with a status code of 200. Overall, the `github.com.grafana.grafana.pkg.middleware` package library provides useful middleware components and utilities for developing web applications with the Grafana framework.