README
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pkg/messaging/kubernetes
Intention
pkg/messaging/kubernetes is the current in-tree backend for
pkg/messaging. It makes the queue contract work by wrapping
controller-runtime manager/controller machinery around one watched Kubernetes
object type and translating reconcile events into messaging.Envelope deliveries.
This is a real backend, but it is not evidence of a mature multi-backend queue abstraction. Today the abstraction has one implementation, and that implementation is essentially controller-runtime reconciliation dressed up as a queue.
What Lives Here
MessageQueue, which owns:- manager construction and leader election when run standalone
- watch registration for one object type
- in-process fan-out to registered consumers
Run(), which starts the manager and controller.SetupWithManager(), which registers the controller with an existing controller-runtime manager.Reconcile(), which loads the watched object and converts it into the minimalmessaging.Envelopeunderstood by consumers.
Relationships
- pkg/messaging defines the replay/retry contract this backend is expected to satisfy.
- pkg/messaging/consumer contains the current main consumer pattern this backend drives.
Invariants
- This backend watches exactly one Kubernetes object type per queue instance.
- Leader election is always enabled because Kubernetes does not partition work like an external message broker would.
- Delivery semantics come from controller-runtime reconciliation:
- active objects are replayed by informer/controller startup behavior
- consumer failure causes reconcile failure and therefore retry
- The emitted envelope is intentionally sparse: resource name plus optional deletion timestamp. Consumers are expected to rehydrate real state from the system of record.
Caveats
- This is not an independent queue model. It is a controller-runtime wrapper with queue-like semantics.
- Only one backend exists today. Future Kafka/NATS-style backends are intended by the abstraction but have not yet pressure-tested it.
Documentation
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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type MessageQueue ¶
MessageQueue implements a message queue like interface using shared informers.
func NewForManager ¶ added in v1.17.0
func NewForManager(object client.Object) *MessageQueue
NewForManager creates a queue that can be registered with an existing manager.
func (*MessageQueue) SetupWithManager ¶ added in v1.17.0
func (q *MessageQueue) SetupWithManager(manager crmanager.Manager, consumers ...messaging.Consumer) error
SetupWithManager registers the queue's controller with an existing manager.
Source Files