42 lines
1.4 KiB
TypeScript
42 lines
1.4 KiB
TypeScript
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import type {
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ISmartMigrationLedgerData,
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} from '../interfaces.js';
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/**
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* Abstract ledger interface — both MongoLedger and S3Ledger implement this.
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*
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* Lifecycle:
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* 1. `init()` — open the underlying store, create empty document if needed
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* 2. `read()` — return the current ledger data
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* 3. `write(data)` — overwrite the ledger with the given data
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* 4. `acquireLock(holderId, ttlMs)` — best-effort lock; returns true on success
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* 5. `releaseLock(holderId)` — clear the lock if we still hold it
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* 6. `close()` — release any resources
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*
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* The ledger data is a single self-contained JSON-serializable object.
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* Both backends store it as a single document (mongo via EasyStore, s3 via
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* a single sidecar object).
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*/
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export abstract class Ledger {
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public abstract init(): Promise<void>;
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public abstract read(): Promise<ISmartMigrationLedgerData>;
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public abstract write(data: ISmartMigrationLedgerData): Promise<void>;
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public abstract acquireLock(holderId: string, ttlMs: number): Promise<boolean>;
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public abstract releaseLock(holderId: string): Promise<void>;
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public abstract close(): Promise<void>;
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}
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/** Build a fresh, empty ledger document. */
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export function emptyLedgerData(): ISmartMigrationLedgerData {
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return {
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currentVersion: null,
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steps: {},
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lock: {
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holder: null,
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acquiredAt: null,
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expiresAt: null,
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},
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checkpoints: {},
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};
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}
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