call metric registration in a go routine and don't block sever startup

[mikehelmick]

Release Note

Create metric descriptors in the background during startup.

[sethvargo]

I think this ctx has a timeout from the parent. I think we should create a new per-request context:

ctx, done := context.WithTimeout(context.Background(), 10*time.Second)
defer done()

If we want to limit the overall time the function can run:

go func() {
  ctx, done := context.WithTimeout(context.Background(), 30*time.Second)
  defer done()


  for _, cmrdesc := range descriptorCreateRequests {
    func() {
      subCtx, done := context.WithTimeout(ctx, 5*time.Second)
      defer done()

      if _, err := mclient.CreateMetricDescriptor(subCtx, cmrdesc); err != nil {
        logger.Errorw(...)
      }
    }()
  }
}()

[mikehelmick]

good catch - updated

[sethvargo]

@mikehelmick approved. You didn't enable auto-approve though, so you'll need to click the button.