refactor(repo-mutex): use effect.ts (#950)

* refactor(repo-mutex): use effect.ts

* refactor(mutext): run with signal to preserve abort reason

README.md

@@ -50,7 +50,7 @@ In order to run Zerobyte, you need to have Docker and Docker Compose installed o
 ```yaml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     cap_add:
@@ -156,7 +156,7 @@ If you only need to back up locally-mounted folders and don't require remote sha
 ```yaml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     ports:
@@ -195,7 +195,7 @@ If you want to backup a local directory on the same host where Zerobyte is runni
 ```diff
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     cap_add:
@@ -270,7 +270,7 @@ Zerobyte can use [rclone](https://rclone.org/) to support 40+ cloud storage prov
    ```diff
    services:
      zerobyte:
-       image: ghcr.io/nicotsx/zerobyte:v0.37
+       image: ghcr.io/nicotsx/zerobyte:v0.38
        container_name: zerobyte
        restart: unless-stopped
        cap_add:

app/client/components/file-browsers/__tests__/snapshot-tree-browser.test.tsx

@@ -224,29 +224,6 @@ describe("SnapshotTreeBrowser", () => {
 		});
 	});
 
-	test("prefetches using the query path when display and query roots differ", async () => {
-		const requests = mockListSnapshotFiles();
-
-		renderSnapshotTreeBrowser();
-
-		const row = await screen.findByRole("button", { name: "project" });
-		const initialRequestCount = requests.length;
-
-		await userEvent.hover(row);
-
-		await waitFor(() => {
-			expect(requests.length).toBe(initialRequestCount + 1);
-		});
-
-		expect(requests.at(-1)).toEqual({
-			shortId: "repo-1",
-			snapshotId: "snap-1",
-			path: "/mnt/project",
-			offset: "0",
-			limit: "500",
-		});
-	});
-
 	test("shows the query root contents when display and query roots differ", async () => {
 		mockListSnapshotFiles();
 

app/client/components/file-browsers/snapshot-tree-browser.tsx

@@ -5,7 +5,6 @@ import { FileBrowser, type FileBrowserUiProps } from "~/client/components/file-b
 import { useFileBrowser } from "~/client/hooks/use-file-browser";
 import { parseError } from "~/client/lib/errors";
 import { isPathWithin, normalizeAbsolutePath } from "@zerobyte/core/utils";
-import { logger } from "~/client/lib/logger";
 
 function createPathPrefixFns(basePath: string) {
 	return {
@@ -84,16 +83,6 @@ export const SnapshotTreeBrowser = (props: SnapshotTreeBrowserProps) => {
 				}),
 			);
 		},
-		prefetchFolder: (displayPath) => {
-			void queryClient
-				.prefetchQuery(
-					listSnapshotFilesOptions({
-						path: { shortId: repositoryId, snapshotId },
-						query: { path: displayPath, offset: 0, limit: pageSize },
-					}),
-				)
-				.catch((e) => logger.error(e));
-		},
 		pathTransform: displayPathFns,
 	});
 

app/client/modules/backups/routes/backup-details.tsx

@@ -63,9 +63,7 @@ export function ScheduleDetailsPage(props: Props) {
 	const queryClient = useQueryClient();
 	const navigate = useNavigate();
 	const searchParams = useSearch({ from: "/(dashboard)/backups/$backupId/" });
-	const [selectedSnapshotId, setSelectedSnapshotId] = useState<string | undefined>(
-		initialSnapshotId ?? loaderData.snapshots?.at(-1)?.short_id,
-	);
+	const [selectedSnapshotId, setSelectedSnapshotId] = useState<string | undefined>(initialSnapshotId);
 	const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
 	const [snapshotToDelete, setSnapshotToDelete] = useState<string | null>(null);
 

app/server/core/__tests__/repository-mutex.test.ts

@@ -134,6 +134,37 @@ describe("RepositoryMutex", () => {
 		expect(repoMutex.isLocked(repoId)).toBe(false);
 	});
 
+	test("should reject aborted queued acquisitions only after waiter cleanup finishes", async () => {
+		const repoId = "abort-waits-for-cleanup";
+		const releaseHolder = await repoMutex.acquireExclusive(repoId, "holder");
+		const controller = new AbortController();
+		const waitingAcquisition = repoMutex.acquireShared(repoId, "waiter", controller.signal);
+
+		try {
+			await new Promise((resolve) => setTimeout(resolve, 50));
+
+			const waitersBeforeAbort = await db.query.repositoryLockWaitersTable.findMany({
+				where: { repositoryId: { eq: repoId } },
+			});
+
+			expect(waitersBeforeAbort.map((waiter) => waiter.operation)).toEqual(["waiter"]);
+
+			controller.abort(new Error("stop"));
+			await expect(waitingAcquisition).rejects.toThrow("stop");
+
+			const waitersAfterAbort = await db.query.repositoryLockWaitersTable.findMany({
+				where: { repositoryId: { eq: repoId } },
+			});
+
+			expect(waitersAfterAbort).toEqual([]);
+			expect(repoMutex.isLocked(repoId)).toBe(true);
+		} finally {
+			releaseHolder();
+			await db.delete(repositoryLockWaitersTable).where(eq(repositoryLockWaitersTable.repositoryId, repoId));
+			await db.delete(repositoryLocksTable).where(eq(repositoryLocksTable.repositoryId, repoId));
+		}
+	});
+
 	test("should allow concurrent shared locks", async () => {
 		const repoId = "concurrent-shared";
 		const release1 = await repoMutex.acquireShared(repoId, "op1");

app/server/core/repository-mutex.ts

@@ -7,6 +7,7 @@ import {
 	type RepositoryLock,
 	type RepositoryLockWaiter,
 } from "../db/schema";
+import { Effect, Exit, Fiber, Schedule, Scope } from "effect";
 
 type LockType = "shared" | "exclusive";
 
@@ -33,59 +34,30 @@ const LOCK_HEARTBEAT_MS = 5_000;
 const LOCK_POLL_MS = 250;
 const LOCK_POLL_CLEANUP_MS = 5_000;
 
+const REPOSITORY_MUTEX_INSTANCE = Symbol.for("zerobyte.repositoryMutex.instance");
+function getRepositoryMutex() {
+	const globalObject = globalThis as typeof globalThis & Record<symbol, RepositoryMutex | undefined>;
+	const mutex = globalObject[REPOSITORY_MUTEX_INSTANCE];
+
+	if (mutex) return mutex;
+
+	const newMutex = new RepositoryMutex();
+	globalObject[REPOSITORY_MUTEX_INSTANCE] = newMutex;
+	return newMutex;
+}
+
 class RepositoryMutex {
 	private ownerId = `owner_${Bun.randomUUIDv7()}`;
-	private heartbeatTimers = new Map<string, ReturnType<typeof setInterval>>();
 	private nextPollCleanupAt = 0;
 
 	private generateLockId(): string {
 		return `lock_${Bun.randomUUIDv7()}`;
 	}
 
-	private abortReason(signal: AbortSignal) {
+	private abortReason(signal: AbortSignal): Error {
 		return signal.reason || new Error("Operation aborted");
 	}
 
-	private throwIfAborted(signal?: AbortSignal) {
-		if (signal?.aborted) {
-			throw this.abortReason(signal);
-		}
-	}
-
-	private releaseIfAborted(releaseLock: () => void, signal?: AbortSignal) {
-		if (!signal?.aborted) return;
-		releaseLock();
-		throw this.abortReason(signal);
-	}
-
-	private waitForPoll(signal?: AbortSignal) {
-		this.throwIfAborted(signal);
-
-		return new Promise<void>((resolve, reject) => {
-			let settled = false;
-			const timeout = setTimeout(() => settle(resolve), LOCK_POLL_MS);
-
-			const onAbort = () => {
-				settle(() => reject(this.abortReason(signal!)));
-			};
-
-			const cleanup = () => {
-				clearTimeout(timeout);
-				signal?.removeEventListener("abort", onAbort);
-			};
-
-			const settle = (callback: () => void) => {
-				if (settled) return;
-
-				settled = true;
-				cleanup();
-				callback();
-			};
-
-			signal?.addEventListener("abort", onAbort, { once: true });
-		});
-	}
-
 	private cleanupExpired(tx: RepositoryMutexTransaction, now: number) {
 		tx.delete(repositoryLocksTable).where(lte(repositoryLocksTable.expiresAt, now)).run();
 		tx.delete(repositoryLockWaitersTable).where(lte(repositoryLockWaitersTable.expiresAt, now)).run();
@@ -181,43 +153,49 @@ class RepositoryMutex {
 		});
 	}
 
-	private tryAcquireImmediately(request: LockRequest, signal?: AbortSignal) {
-		const locks = this.tryAcquireManyRows([request]);
-		if (!locks || locks.length === 0) return null;
+	private tryAcquireImmediately(request: LockRequest) {
+		return Effect.gen(this, function* () {
+			const locks = this.tryAcquireManyRows([request]);
+			if (!locks || locks.length === 0) return null;
 
-		const [lock] = locks;
-		const releaseLock = this.createRelease(lock);
-		this.releaseIfAborted(releaseLock, signal);
-
-		return releaseLock;
+			const [lock] = locks;
+			return yield* this.createRelease(lock);
+		});
 	}
 
 	private createWaiter(request: LockRequest, waiterId: string) {
-		const now = Date.now();
-
-		db.transaction((tx) => {
-			this.cleanupExpired(tx, now);
-			tx.insert(repositoryLockWaitersTable)
-				.values({
-					id: waiterId,
-					repositoryId: request.repositoryId,
-					type: request.type,
-					operation: request.operation,
-					ownerId: this.ownerId,
-					requestedAt: now,
-					expiresAt: now + LOCK_LEASE_MS,
-					heartbeatAt: now,
-				})
-				.run();
+		return Effect.sync(() => {
+			const now = Date.now();
+			db.transaction((tx) => {
+				this.cleanupExpired(tx, now);
+				tx.insert(repositoryLockWaitersTable)
+					.values({
+						id: waiterId,
+						repositoryId: request.repositoryId,
+						type: request.type,
+						operation: request.operation,
+						ownerId: this.ownerId,
+						requestedAt: now,
+						expiresAt: now + LOCK_LEASE_MS,
+						heartbeatAt: now,
+					})
+					.run();
+			});
 		});
 	}
 
 	private deleteWaiter(waiterId: string) {
-		db.delete(repositoryLockWaitersTable)
-			.where(
-				and(eq(repositoryLockWaitersTable.id, waiterId), eq(repositoryLockWaitersTable.ownerId, this.ownerId)),
-			)
-			.run();
+		return Effect.sync(() =>
+			db
+				.delete(repositoryLockWaitersTable)
+				.where(
+					and(
+						eq(repositoryLockWaitersTable.id, waiterId),
+						eq(repositoryLockWaitersTable.ownerId, this.ownerId),
+					),
+				)
+				.run(),
+		);
 	}
 
 	private deleteWaiterRow(tx: RepositoryMutexTransaction, waiterId: string): void {
@@ -293,97 +271,49 @@ class RepositoryMutex {
 		});
 	}
 
-	private async waitForQueuedLock(request: LockRequest, signal?: AbortSignal) {
-		this.throwIfAborted(signal);
-
+	private waitForQueuedLock(request: LockRequest) {
 		const waiterId = this.generateLockId();
-		this.createWaiter(request, waiterId);
-		this.startHeartbeat("waiter", waiterId);
 
-		try {
-			while (true) {
-				this.throwIfAborted(signal);
-
-				const attempt = this.tryPromoteWaiter(waiterId);
+		const attempt = Effect.sync(() => this.tryPromoteWaiter(waiterId)).pipe(
+			Effect.flatMap((attempt) => {
 				if (attempt.status === "acquired") {
-					this.stopHeartbeat(waiterId);
-					const releaseLock = this.createRelease(attempt.lock);
-					this.releaseIfAborted(releaseLock, signal);
-
-					return releaseLock;
+					return Effect.succeed(attempt.lock);
 				}
 
 				if (attempt.status === "missing") {
-					this.createWaiter(request, waiterId);
-					this.startHeartbeat("waiter", waiterId);
+					return Effect.gen(this, function* () {
+						yield* this.createWaiter(request, waiterId);
+						yield* this.startHeartbeat("waiter", waiterId);
+
+						return yield* Effect.fail("retry");
+					});
 				}
 
-				await this.waitForPoll(signal);
-			}
-		} catch (error) {
-			this.stopHeartbeat(waiterId);
-			this.deleteWaiter(waiterId);
-			this.release({ id: waiterId });
-			throw error;
-		}
-	}
+				return Effect.fail("retry");
+			}),
+		);
 
-	async acquireShared(repositoryId: string, operation: string, signal?: AbortSignal) {
-		this.throwIfAborted(signal);
+		const cleanupAbandonedWaiter = Effect.gen(this, function* () {
+			yield* this.deleteWaiter(waiterId);
+			yield* this.release({ id: waiterId });
+		});
 
-		const request: LockRequest = { repositoryId, type: "shared", operation };
-		const releaseLock = this.tryAcquireImmediately(request, signal);
-		if (releaseLock) {
-			return releaseLock;
-		}
+		return Effect.scoped(
+			Effect.gen(this, function* () {
+				const lock = yield* attempt.pipe(
+					Effect.retry(Schedule.spaced(LOCK_POLL_MS)),
+					Effect.onExit((exit) => {
+						if (Exit.isSuccess(exit)) {
+							return Effect.void;
+						}
 
-		logger.debug(`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation}`);
-		return await this.waitForQueuedLock(request, signal);
-	}
+						return cleanupAbandonedWaiter;
+					}),
+				);
 
-	async acquireExclusive(repositoryId: string, operation: string, signal?: AbortSignal) {
-		this.throwIfAborted(signal);
-
-		const request: LockRequest = { repositoryId, type: "exclusive", operation };
-		const releaseLock = this.tryAcquireImmediately(request, signal);
-		if (releaseLock) {
-			logger.debug(`[Mutex] Acquired exclusive lock for repo ${repositoryId}: ${operation}`);
-			return releaseLock;
-		}
-
-		logger.debug(`[Mutex] Waiting for exclusive lock on repo ${repositoryId}: ${operation}`);
-		const queuedReleaseLock = await this.waitForQueuedLock(request, signal);
-		logger.debug(`[Mutex] Acquired exclusive lock for repo ${repositoryId}: ${operation}`);
-		return queuedReleaseLock;
-	}
-
-	async acquireMany(requests: LockRequest[], signal?: AbortSignal) {
-		this.throwIfAborted(signal);
-
-		if (requests.length === 0) {
-			return () => {};
-		}
-
-		const seenRepositoryIds = new Set<string>();
-		for (const request of requests) {
-			if (seenRepositoryIds.has(request.repositoryId)) {
-				throw new Error(`Duplicate repository lock request: ${request.repositoryId}`);
-			}
-			seenRepositoryIds.add(request.repositoryId);
-		}
-
-		const sortedRequests = [...requests].sort((a, b) => a.repositoryId.localeCompare(b.repositoryId));
-		while (true) {
-			const locks = this.tryAcquireManyRows(sortedRequests);
-			if (locks) {
-				const releaseLocks = this.createReleaseMany(locks);
-				this.releaseIfAborted(releaseLocks, signal);
-
-				return releaseLocks;
-			}
-
-			await this.waitForPoll(signal);
-		}
+				return yield* this.createRelease(lock);
+			}),
+		);
 	}
 
 	isLocked(repositoryId: string) {
@@ -396,69 +326,91 @@ class RepositoryMutex {
 	}
 
 	private createReleaseMany(locks: AcquiredLock[]) {
-		const releases = locks.map((lock) => this.createRelease(lock));
-		let released = false;
+		return Effect.gen(this, function* () {
+			const releases = yield* Effect.all(locks.map((lock) => this.createRelease(lock)));
+			let released = false;
 
-		return () => {
-			if (released) return;
+			return () => {
+				if (released) return;
 
-			released = true;
-			for (const release of releases.toReversed()) {
-				release();
-			}
-		};
+				released = true;
+				for (const release of releases.toReversed()) {
+					release();
+				}
+			};
+		});
 	}
 
 	private createRelease(lock: AcquiredLock) {
-		this.startHeartbeat("lock", lock.id);
-		let released = false;
+		return Effect.gen(this, function* () {
+			const heartbeatFiber = yield* this.startHeartbeat("lock", lock.id);
+			let released = false;
 
-		return () => {
-			if (released) return;
+			return () => {
+				if (released) return;
 
-			released = true;
-			this.stopHeartbeat(lock.id);
-			this.release(lock);
-		};
+				released = true;
+				Effect.runFork(Fiber.interrupt(heartbeatFiber));
+				Effect.runSync(this.release(lock));
+			};
+		});
 	}
 
 	private release(lock: Pick<AcquiredLock, "id">) {
-		const releasedLock = db.transaction((tx) => {
-			const row = tx.query.repositoryLocksTable
-				.findFirst({ where: { AND: [{ id: { eq: lock.id } }, { ownerId: { eq: this.ownerId } }] } })
-				.sync();
+		return Effect.gen(this, function* () {
+			const releasedLock = yield* Effect.sync(() =>
+				db.transaction((tx) => {
+					const row = tx.query.repositoryLocksTable
+						.findFirst({ where: { AND: [{ id: { eq: lock.id } }, { ownerId: { eq: this.ownerId } }] } })
+						.sync();
 
-			if (!row) return null;
+					if (!row) return null;
 
-			tx.delete(repositoryLocksTable)
-				.where(and(eq(repositoryLocksTable.id, lock.id), eq(repositoryLocksTable.ownerId, this.ownerId)))
-				.run();
+					tx.delete(repositoryLocksTable)
+						.where(
+							and(eq(repositoryLocksTable.id, lock.id), eq(repositoryLocksTable.ownerId, this.ownerId)),
+						)
+						.run();
 
-			return row;
+					return row;
+				}),
+			);
+
+			if (!releasedLock) return;
+
+			const duration = Date.now() - releasedLock.acquiredAt;
+
+			yield* logger.effect.debug(
+				`[Mutex] Released ${releasedLock.type} lock for repo ${releasedLock.repositoryId}: ${releasedLock.operation} (held for ${duration}ms)`,
+			);
 		});
-
-		if (!releasedLock) return;
-
-		const duration = Date.now() - releasedLock.acquiredAt;
-		logger.debug(
-			`[Mutex] Released ${releasedLock.type} lock for repo ${releasedLock.repositoryId}: ${releasedLock.operation} (held for ${duration}ms)`,
-		);
 	}
 
-	private startHeartbeat(target: HeartbeatTarget, lockId: string) {
-		this.stopHeartbeat(lockId);
-
-		const heartbeat = () => {
+	private startHeartbeat(
+		target: "waiter",
+		lockId: string,
+	): Effect.Effect<Fiber.RuntimeFiber<void, never>, never, Scope.Scope>;
+	private startHeartbeat(
+		target: "lock",
+		lockId: string,
+	): Effect.Effect<Fiber.RuntimeFiber<void, never>, never, never>;
+	private startHeartbeat(
+		target: HeartbeatTarget,
+		lockId: string,
+	): Effect.Effect<Fiber.RuntimeFiber<unknown, never>, never, Scope.Scope> {
+		const heartbeat = Effect.gen(this, function* () {
 			const now = Date.now();
 			const values = { heartbeatAt: now, expiresAt: now + LOCK_LEASE_MS };
 
-			try {
-				if (target === "lock") {
+			if (target === "lock") {
+				yield* Effect.try(() => {
 					db.update(repositoryLocksTable)
 						.set(values)
 						.where(and(eq(repositoryLocksTable.id, lockId), eq(repositoryLocksTable.ownerId, this.ownerId)))
 						.run();
-				} else {
+				});
+			} else {
+				yield* Effect.try(() => {
 					db.update(repositoryLockWaitersTable)
 						.set(values)
 						.where(
@@ -468,29 +420,142 @@ class RepositoryMutex {
 							),
 						)
 						.run();
-				}
-			} catch (error) {
-				logger.warn(`[Mutex] Failed to heartbeat ${target} ${lockId}: ${String(error)}`);
+				});
 			}
-		};
+		}).pipe(
+			Effect.catchAll((error) =>
+				logger.effect.warn(`[Mutex] Failed to heartbeat ${target} ${lockId}: ${String(error)}`),
+			),
+		);
 
-		const timer = setInterval(heartbeat, LOCK_HEARTBEAT_MS);
-		if (timer && "unref" in timer) {
-			timer.unref();
+		const repeat = heartbeat.pipe(Effect.repeat(Schedule.spaced(LOCK_HEARTBEAT_MS)));
+
+		if (target === "waiter") {
+			// For waiters, we can stop heartbeating when the releaser is dropped, so we use a scoped fiber
+			return repeat.pipe(Effect.forkScoped);
 		}
 
-		this.heartbeatTimers.set(lockId, timer);
+		// For locks, the heartbeat must outlive the acquire scope.
+		// It is interrupted manually by the returned release function.
+		// TODO: max lifetime for lock heartbeats to prevent leaks if the releaser is never called?
+		return repeat.pipe(Effect.forkDaemon);
 	}
 
-	private stopHeartbeat(lockId: string) {
-		const timer = this.heartbeatTimers.get(lockId);
-		if (!timer) {
-			return;
+	private acquireSharedEffect(repositoryId: string, operation: string) {
+		return Effect.gen(this, function* () {
+			const request: LockRequest = { repositoryId, type: "shared", operation };
+			const releaseLock = yield* this.tryAcquireImmediately(request);
+			if (releaseLock) return releaseLock;
+
+			yield* logger.effect.debug(`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation}`);
+			return yield* this.waitForQueuedLock(request);
+		});
+	}
+
+	private acquireExclusiveEffect(repositoryId: string, operation: string) {
+		return Effect.gen(this, function* () {
+			const request: LockRequest = { repositoryId, type: "exclusive", operation };
+			const releaseLock = yield* this.tryAcquireImmediately(request);
+			if (releaseLock) {
+				yield* logger.effect.debug(`[Mutex] Acquired exclusive lock for repo ${repositoryId}: ${operation}`);
+				return releaseLock;
+			}
+
+			yield* logger.effect.debug(`[Mutex] Waiting for exclusive lock on repo ${repositoryId}: ${operation}`);
+			const queuedReleaseLock = yield* this.waitForQueuedLock(request);
+			yield* logger.effect.debug(`[Mutex] Acquired exclusive lock for repo ${repositoryId}: ${operation}`);
+			return queuedReleaseLock;
+		});
+	}
+
+	private acquireManyEffect(requests: LockRequest[]) {
+		return Effect.gen(this, function* () {
+			if (requests.length === 0) {
+				return () => {};
+			}
+
+			const seenRepositoryIds = new Set<string>();
+			for (const request of requests) {
+				if (seenRepositoryIds.has(request.repositoryId)) {
+					throw new Error(`Duplicate repository lock request: ${request.repositoryId}`);
+				}
+				seenRepositoryIds.add(request.repositoryId);
+			}
+
+			const sortedRequests = [...requests].sort((a, b) => a.repositoryId.localeCompare(b.repositoryId));
+
+			const locks = yield* Effect.sync(() => this.tryAcquireManyRows(sortedRequests)).pipe(
+				Effect.flatMap((locks) => {
+					if (locks) return Effect.succeed(locks);
+					return Effect.fail("retry");
+				}),
+				Effect.retry(Schedule.spaced(LOCK_POLL_MS)),
+			);
+
+			return yield* this.createReleaseMany(locks);
+		});
+	}
+
+	private runWithSignal<A, E>(effect: Effect.Effect<A, E>, signal?: AbortSignal) {
+		if (!signal) return Effect.runPromise(effect);
+
+		if (signal.aborted) {
+			return Promise.reject(this.abortReason(signal));
 		}
 
-		clearInterval(timer);
-		this.heartbeatTimers.delete(lockId);
+		return new Promise<A>((resolve, reject) => {
+			const fiber = Effect.runFork(effect);
+			let settled = false;
+			let aborting = false;
+
+			const complete = (callback: () => void) => {
+				if (settled) return;
+
+				settled = true;
+				signal.removeEventListener("abort", onAbort);
+				callback();
+			};
+
+			const onAbort = () => {
+				aborting = true;
+				Effect.runPromise(Fiber.interrupt(fiber)).then(
+					(exit) =>
+						complete(() => {
+							if (Exit.isSuccess(exit)) {
+								resolve(exit.value);
+								return;
+							}
+
+							reject(this.abortReason(signal));
+						}),
+					(error) => complete(() => reject(error)),
+				);
+			};
+
+			signal.addEventListener("abort", onAbort, { once: true });
+
+			Effect.runPromise(Fiber.join(fiber)).then(
+				(value) => complete(() => resolve(value)),
+				(error) => {
+					if (!aborting) {
+						complete(() => reject(error));
+					}
+				},
+			);
+		});
+	}
+
+	async acquireShared(repositoryId: string, operation: string, signal?: AbortSignal) {
+		return await this.runWithSignal(this.acquireSharedEffect(repositoryId, operation), signal);
+	}
+
+	async acquireExclusive(repositoryId: string, operation: string, signal?: AbortSignal) {
+		return await this.runWithSignal(this.acquireExclusiveEffect(repositoryId, operation), signal);
+	}
+
+	async acquireMany(requests: LockRequest[], signal?: AbortSignal) {
+		return await this.runWithSignal(this.acquireManyEffect(requests), signal);
 	}
 }
 
-export const repoMutex = new RepositoryMutex();
+export const repoMutex = getRepositoryMutex();

app/server/modules/repositories/__tests__/repositories.service.test.ts

@@ -208,6 +208,141 @@ describe("repositoriesService repository stats", () => {
 	});
 });
 
+describe("repositoriesService.listSnapshotFiles", () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	test("limits concurrent restic ls commands per repository", async () => {
+		const repository = await createTestRepository(session.organizationId);
+		let active = 0;
+		let maxActive = 0;
+		let releaseAll = false;
+		let exclusiveAcquired = false;
+		let releaseExclusive: (() => void) | undefined;
+		let exclusivePromise: Promise<() => void> | undefined;
+		const releaseWaiters: Array<() => void> = [];
+		const exclusiveController = new AbortController();
+
+		const releaseWaitingCommands = () => {
+			const waiters = releaseWaiters.splice(0);
+			for (const release of waiters) {
+				release();
+			}
+		};
+
+		const resolveWithin = async <T>(promise: Promise<T>, timeoutMs: number) => {
+			return await new Promise<T>((resolve, reject) => {
+				const timeout = setTimeout(() => {
+					reject(new Error(`Expected promise to resolve within ${timeoutMs}ms`));
+				}, timeoutMs);
+
+				promise.then(
+					(value) => {
+						clearTimeout(timeout);
+						resolve(value);
+					},
+					(error) => {
+						clearTimeout(timeout);
+						reject(error);
+					},
+				);
+			});
+		};
+
+		const lsSpy = vi.spyOn(restic, "ls").mockImplementation((_config, snapshotId, _path, options) =>
+			Effect.promise(async () => {
+				active++;
+				maxActive = Math.max(maxActive, active);
+
+				try {
+					if (!releaseAll) {
+						await new Promise<void>((resolve) => releaseWaiters.push(resolve));
+					}
+
+					return {
+						snapshot: {
+							id: snapshotId,
+							short_id: snapshotId,
+							time: new Date().toISOString(),
+							tree: "tree",
+							paths: ["/"],
+							hostname: "host",
+							struct_type: "snapshot" as const,
+							message_type: "snapshot" as const,
+						},
+						nodes: [],
+						pagination: {
+							offset: options.offset ?? 0,
+							limit: options.limit ?? 500,
+							total: 0,
+							hasMore: false,
+						},
+					};
+				} finally {
+					active--;
+				}
+			}),
+		);
+
+		const calls = Array.from({ length: 4 }, (_, index) =>
+			withContext({ organizationId: session.organizationId, userId: session.user.id }, () =>
+				repositoriesService.listSnapshotFiles(repository.shortId, `snapshot-${index}`, "/", {
+					offset: 0,
+					limit: 100,
+				}),
+			),
+		);
+
+		try {
+			await waitForExpect(() => {
+				expect(releaseWaiters).toHaveLength(2);
+			});
+			expect(maxActive).toBe(2);
+
+			exclusivePromise = repoMutex
+				.acquireExclusive(repository.id, "delete", exclusiveController.signal)
+				.then((release) => {
+					exclusiveAcquired = true;
+					releaseExclusive = release;
+					return release;
+				});
+
+			releaseWaitingCommands();
+
+			releaseExclusive = await resolveWithin(exclusivePromise, 2000);
+			expect(exclusiveAcquired).toBe(true);
+			expect(active).toBe(0);
+
+			releaseExclusive();
+			releaseExclusive = undefined;
+
+			await waitForExpect(() => {
+				expect(releaseWaiters).toHaveLength(2);
+			});
+			expect(maxActive).toBe(2);
+
+			releaseWaitingCommands();
+			await Promise.all(calls);
+		} finally {
+			if (releaseExclusive) {
+				releaseExclusive();
+			} else {
+				exclusiveController.abort();
+			}
+			releaseAll = true;
+			releaseWaitingCommands();
+			await Promise.allSettled(calls);
+			if (exclusivePromise) {
+				await Promise.allSettled([exclusivePromise]);
+			}
+		}
+
+		expect(lsSpy).toHaveBeenCalledTimes(4);
+		expect(maxActive).toBeLessThanOrEqual(2);
+	});
+});
+
 describe("repositoriesService.dumpSnapshot", () => {
 	afterEach(() => {
 		vi.restoreAllMocks();

app/server/modules/repositories/repositories.service.ts

@@ -42,6 +42,7 @@ import type { ParsedTask, TaskInput } from "../tasks/tasks.schemas";
 import { Effect } from "effect";
 
 const runningDoctors = new Map<string, AbortController>();
+const lsLimiters = new Map<string, Effect.Semaphore>();
 const RESTORE_TASK_RESOURCE_TYPE = "repository";
 
 type RestoreTaskInput = Extract<TaskInput, { kind: "restore" }>;
@@ -99,6 +100,15 @@ const updateActiveRestoreTask = (restoreId: string, eventName: string, update: (
 	}
 };
 
+const getLsLimiter = (repositoryId: string) => {
+	let limiter = lsLimiters.get(repositoryId);
+	if (!limiter) {
+		limiter = Effect.runSync(Effect.makeSemaphore(2));
+		lsLimiters.set(repositoryId, limiter);
+	}
+	return limiter;
+};
+
 const findActiveRestoreTask = (
 	organizationId: string,
 	repositoryShortId: string,
@@ -469,36 +479,43 @@ const listSnapshotFiles = async (
 		};
 	}
 
-	const releaseLock = await repoMutex.acquireShared(repository.id, `ls:${snapshotId}`);
+	const limiter = getLsLimiter(repository.id);
+	await runEffectPromise(limiter.take(1));
+
 	try {
-		const result = await runEffectPromise(
-			restic.ls(repository.config, snapshotId, path, { organizationId, offset, limit }),
-		);
+		const releaseLock = await repoMutex.acquireShared(repository.id, `ls:${snapshotId}`);
+		try {
+			const result = await runEffectPromise(
+				restic.ls(repository.config, snapshotId, path, { organizationId, offset, limit }),
+			);
 
-		if (!result.snapshot) {
-			throw new NotFoundError("Snapshot not found or empty");
+			if (!result.snapshot) {
+				throw new NotFoundError("Snapshot not found or empty");
+			}
+
+			const response = {
+				snapshot: {
+					id: result.snapshot.id,
+					short_id: result.snapshot.short_id,
+					time: result.snapshot.time,
+					hostname: result.snapshot.hostname,
+					paths: result.snapshot.paths,
+				},
+				files: result.nodes,
+				offset: result.pagination.offset,
+				limit: result.pagination.limit,
+				total: result.pagination.total,
+				hasMore: result.pagination.hasMore,
+			};
+
+			cache.set(cacheKey, result);
+
+			return response;
+		} finally {
+			releaseLock();
 		}
-
-		const response = {
-			snapshot: {
-				id: result.snapshot.id,
-				short_id: result.snapshot.short_id,
-				time: result.snapshot.time,
-				hostname: result.snapshot.hostname,
-				paths: result.snapshot.paths,
-			},
-			files: result.nodes,
-			offset: result.pagination.offset,
-			limit: result.pagination.limit,
-			total: result.pagination.total,
-			hasMore: result.pagination.hasMore,
-		};
-
-		cache.set(cacheKey, result);
-
-		return response;
 	} finally {
-		releaseLock();
+		await runEffectPromise(limiter.release(1));
 	}
 };
 

apps/docs/content/docs/guides/provisioning.mdx

@@ -99,7 +99,7 @@ Mount the provisioning file and set `PROVISIONING_PATH`:
 ```yaml docker-compose.yml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     environment:
       - PROVISIONING_PATH=/config/provisioning.json
     volumes:

apps/docs/content/docs/guides/reverse-proxy.mdx

@@ -100,7 +100,7 @@ If you run Traefik as your reverse proxy, add labels to the Zerobyte service in
 ```yaml docker-compose.yml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     environment:

apps/docs/content/docs/guides/tailscale.mdx

@@ -52,7 +52,7 @@ services:
       - "4096:4096"
 
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     # Uncomment if you need remote mounts (NFS/SMB/WebDAV):

apps/docs/content/docs/installation.mdx

@@ -52,7 +52,7 @@ Create a `docker-compose.yml` file with the following configuration:
 ```yaml docker-compose.yml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     cap_add:
@@ -182,7 +182,7 @@ If you only need to back up locally mounted directories and don't require remote
 ```yaml docker-compose.yml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     ports:
@@ -259,7 +259,7 @@ If you use provisioning, Zerobyte can resolve secrets from environment variables
 ```yaml docker-compose.yml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     cap_add:

apps/docs/content/docs/quickstart.mdx

@@ -111,7 +111,7 @@ Update your `docker-compose.yml` to mount the directory you want to backup:
 ```yaml
 services:
   zerobyte:
-    image: ghcr.io/nicotsx/zerobyte:v0.37
+    image: ghcr.io/nicotsx/zerobyte:v0.38
     container_name: zerobyte
     restart: unless-stopped
     # ... other configuration ...