Documentation
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Overview ¶
Package ackcursor is the durable, acknowledgement-gated cursor behind every at-least-once delivery of an ordered, hash-chained row stream: federation's audit forwarder today, the per-run spool replay over the runner stream and acknowledged SIEM delivery next. The cursor moves only after the receiver acknowledges; a re-sent row is recognised by seq + row hash (a local table reset can reuse a seq, so the position keeps both).
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Cursor ¶
type Cursor[T any] struct { Source Source[T] Sink Sink[T] Store Store // Key reads a row's seq and hash. Key func(T) Pos // Batch is the most rows delivered per Step. Batch int // OnReset is called, before the position is cleared, when the row at the // cursor is gone or changed; its argument is the position that failed. OnReset func(Pos) // contains filtered or unexported fields }
Cursor runs the batch loop. Not safe for concurrent use.
func (*Cursor[T]) Step ¶
Step delivers the next batch and advances the position past what was acknowledged. more is true when the batch was full, so the caller should step again without waiting. On error the position is unchanged, except that a reset already made durable stays reset.
The row at the position and the batch after it come from one read. If that row is gone or carries another hash the stream was reset: rows after it would link to nothing the receiver holds, so Step starts over from the beginning (the receiver skips what it already holds).
type Pos ¶
Pos is a position in the stream: the seq of the last acknowledged row and that row's hash. The zero Pos is the start of the stream.
type Sink ¶
Sink delivers one batch. rows is empty when there is nothing to send (a sink with a liveness signal sends it then). It returns the highest seq the receiver acknowledged; the cursor never moves past the rows read or backwards, so a sink that skips rows it cannot send returns the last seq of the batch.
Source Files