impossible to write timestamps to status objects without causing controller to loop

[clux]

A small diff to a controller like:

diff --git src/manager.rs src/manager.rs
index 544b495..277f25c 100644
--- src/manager.rs
+++ src/manager.rs
@@ -26,9 +26,10 @@ pub struct FooSpec {
     info: String,
 }
 
-#[derive(Deserialize, Serialize, Clone, Debug, Default, JsonSchema)]
+#[derive(Deserialize, Serialize, Clone, Debug, JsonSchema)]
 pub struct FooStatus {
     is_bad: bool,
+    last_updated: Option<DateTime<Utc>>,
 }
 
 // Context for our reconciler
@@ -54,6 +55,7 @@ async fn reconcile(foo: Foo, ctx: Context<Data>) -> Result<ReconcilerAction, Err
     let new_status = serde_json::to_vec(&json!({
         "status": FooStatus {
             is_bad: foo.spec.info.contains("bad"),
+            last_updated: Some(Utc::now()),
         }
     }))
     .context(SerializationFailed)?;

Causes the controller to spin repeatedly:

Dec 23 13:46:51.991  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:51.997  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.003  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.008  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.014  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.020  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.027  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.032  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.037  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.056  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.074  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.086  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.100  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })
Dec 23 13:46:52.113  INFO controller::manager: Reconciled (ObjectRef { kind: (), name: "bad", namespace: Some("default") }, ReconcilerAction { requeue_after: Some(1800s) })

Related to #318 and #279. It was slightly annoying then, but now it's actually preventing things, so we have to tackle it one way or another.

[nightkr]

On one hand, it could be argued that the client shouldn't send no-op patches to the apiserver anyway. On the other, doing that kind of diffing locally could be pretty error-prone..

Then again, any local filtering mechanism would need to implement the same logic anyway.

[clux]

On one hand, it could be argued that the client shouldn't send no-op patches to the apiserver anyway. On the other, doing that kind of diffing locally could be pretty error-prone..

Oh, that is a good point. Yeah, this probably isn't a bug.
Sorry, just second guessing everything before the release 😅

[clux]

hm, then again, doing a noop update to the server is kind of useful to a controller to indicate that work has been done and the thing isn't dead...

EDIT: particularly if the only thing changes was the status object. It's a bit difficult to check every single status property before writing our current one in a reconciler. At the very least it will cause very hairy reconcilers.

[clux]

Closing in favour of #279 - will explain there.