gizlang:journal

Shared log coordinates. Durable publication, retention and product events remain with their storage owners; no database or wire adapter is imported.

import * as Journal from "gizlang:journal";

Types

Position

type Position = { shard: string; history: string; sequence: i64; operation: i64; }

A place in a journal: its shard, its history, the sequence of the commit and the operation within it.

• shard: string
• history: string
• sequence: i64
• operation: i64

Acknowledgement

type Acknowledgement = { floor: i64; observed: Position; }

Explicit acceptance of terminal outcomes through a request floor and cut. Product owners retain pending intents and decide what is safely collectible.

• floor: i64
• observed: gizlang_journal.Position

Functions

validAcknowledgement

function validAcknowledgement(acknowledgement: Acknowledgement, history: string, maximumCut: i64): bool

Whether ACKNOWLEDGEMENT is valid for HISTORY: it observes the end of a commit of HISTORY at most MAXIMUMCUT.

boundary

function boundary(history: string, sequence: i64): Position

The position at the end of commit SEQUENCE of HISTORY.

compare

function compare(a: Position, b: Position): i64 throws string

Histories are incomparable; a new history requires a snapshot.

Effects: fail.

cursor

function cursor(position: Position): string

Exact coordinates encoded in an opaque, URL-safe, checksummed envelope.

Effects: fail.

readCursor

function readCursor(text: string): Position throws string

The position that text spells (the form cursor writes), or why it is not one.

Effects: fail.

retained

function retained(position: Position, history: string, first: i64, last: i64): bool

Whether POSITION is in HISTORY and in the commits FIRST to LAST that the journal keeps.

Effects: fail.

Constants

COMMIT_END

const COMMIT_END = 9223372036854775807

The position that no commit reaches: the open end of a range.

SHARD

const SHARD = "local"

The name of the shard of a local journal.