Goroutines inside a middleware

When starting new Goroutines inside a middleware or handler, you SHOULD NOT use the original context inside it, you have to use a read-only copy.

  1. func main() {
  2.     r := gin.Default()
  4.     r.GET("/long_async", func(c *gin.Context) {
  5.         // create copy to be used inside the goroutine
  6.         cCp := c.Copy()
  7.         go func() {
  8.             // simulate a long task with time.Sleep(). 5 seconds
  9.             time.Sleep(5 * time.Second)
  11.             // note that you are using the copied context "cCp", IMPORTANT
  12.             log.Println("Done! in path " + cCp.Request.URL.Path)
  13.         }()
  14.     })
  16.     r.GET("/long_sync", func(c *gin.Context) {
  17.         // simulate a long task with time.Sleep(). 5 seconds
  18.         time.Sleep(5 * time.Second)
  20.         // since we are NOT using a goroutine, we do not have to copy the context
  21.         log.Println("Done! in path " + c.Request.URL.Path)
  22.     })
  24.     // Listen and serve on 0.0.0.0:8080
  25.     r.Run(":8080")
  26. }