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 already part of an active batch — the controller performs a single intent CAS on the batch (advancing it to BatchStateCancelling) and hands off to the speculate controller by publishing the batch ID to TopicKeySpeculate. The speculate controller then owns: cancelling any in-flight Build entity for the batch, fanning out to dependents, the terminal CAS to BatchStateCancelled, and publishing to conclude. Cancel does no terminal write and no downstream fan-out on the batch path.
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 (score, 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 the Cancelling write skips the mark-cancelling step and proceeds straight to the batch lookup. On the batch path, re-delivery against an already Cancelling batch re-publishes to TopicKeySpeculate (a cheap no-op nudge the speculate controller absorbs).
Concurrent producers surface as storage.ErrVersionMismatch; the controller returns the wrapped error as-is and relies on the base controller layer to classify it as retryable 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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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