Contexts complient with kube-builder

[kuritka]

In order to migration operator-sdk 1.0 we should use contexts to be kube-builder compliant. To achieve this, I reuse default Background context from reconciliation loop. see: https://book.kubebuilder.io/cronjob-tutorial/controller-implementation.html#implementing-a-controller;

func (r *CronJobReconciler) Reconcile(req ctrl.Request) (ctrl.Result, error) {
    ctx := context.Background()
    log := r.Log.WithValues("cronjob", req.NamespacedName)

I changed

• depresolver doesn't hold context internally
• update tests
• use default context instead of context.TODO() within reconciliation queue

[ytsarev]

Btw I was always wondering of a real difference between TODO() vs Background()

I guess I found the answer https://essential-go.programming-books.io/context-todo-vs-context-background-d5224e27ff724a33a79cb4e03a5eb333#:~:text=TODO%20returns%20a%20non%2Dnil%2C%20empty%20Context%20.&text=Background%20returns%20a%20non%2Dnil,level%20Context%20for%20incoming%20requests.

The difference is NONE, lol

[ytsarev]

Why do we still use TODO() there?

[kuritka]

@ytsarev good question: The point is that you are creating i.e. WithCancel context from existing context.

If you use Background context, you explicitly say: Hey, I'm using context from the top of the tree, usually main package and this context will instantiate another context(s) WithCancel, WithDeadline...

If you use context.TODO() you explicitly say: function just requires some context argument so I will pass TODO which is doing nothing, just to compile. For instance, our tests..

[ytsarev]

@kuritka cool, makes total sense