Documentation
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Overview ¶
Package cancel implements the orchestrator-side cancel controller.
The controller consumes CancelRequest messages from the cancel topic and records the user's cancellation intent. Two distinct paths exist after the request-level intent (RequestStateCancelling) is recorded:
The request has not yet been enrolled into a batch — the controller transitions Cancelling → RequestStateCancelled directly and emits a RequestStatusCancelled log entry. This path is fully owned by the cancel controller.
The request is associated with one or more batch attempts — the controller records cancellation intent on every cancellable attempt and hands each one to speculate. Creating attempts are ignored because their reverse indexes may be incomplete, while Merging and terminal attempts retain their existing outcome for conclude to reconcile.
The split exists so that the terminal write and the work that must precede it (cancelling builds, respeculating dependents) live in the same controller — speculate is the single writer of every non-Cancelling batch state and is already wired with the build/dependent stores. Forward-progress controllers (build, buildsignal, merge) observe BatchStateCancelling via IsBatchStateHalted and short-circuit while speculate drives the batch to its terminal state.
The controller is idempotent: re-delivery of the same CancelRequest after the terminal request transition is a no-op. Re-delivery after a Cancelling write skips that CAS, finds every batch ID containing the request again, and republishes matching attempts already in BatchStateCancelling.
Concurrent producers surface as the intrinsically retryable storage.ErrVersionMismatch; the controller returns the wrapped error as-is so the next attempt sees the new state and takes the other branch. storage.ErrNotFound on the initial Get (the start controller has not yet persisted the request) is returned as-is for the same reason.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Controller ¶
type Controller struct {
// contains filtered or unexported fields
}
Controller handles cancel queue messages. Implements consumer.Controller.
func NewController ¶
func NewController( logger *zap.SugaredLogger, scope tally.Scope, store storage.Storage, registry consumer.TopicRegistry, topicKey consumer.TopicKey, consumerGroup string, ) *Controller
NewController creates a new cancel controller for the orchestrator.
func (*Controller) ConsumerGroup ¶
func (c *Controller) ConsumerGroup() string
ConsumerGroup returns the consumer group for offset tracking.
func (*Controller) Name ¶
func (c *Controller) Name() string
Name returns the controller name for logging and metrics.
func (*Controller) Process ¶
Process processes a cancel delivery from the queue. Returns nil to ack (success), or error to nack (retry).
func (*Controller) TopicKey ¶
func (c *Controller) TopicKey() consumer.TopicKey
TopicKey returns the topic key this controller subscribes to.
Source Files