Function tryAcquireLockDir

packages/core/src/util/effect-flock.ts:169–217

(lockDir: string, key: string)

      type Handle = { token: string; metaPath: string; heartbeatPath: string; lockDir: string }

      const tryAcquireLockDir = (lockDir: string, key: string) =>
        Effect.gen(function* () {
          const token = randomUUID()
          const metaPath = path.join(lockDir, "meta.json")
          const heartbeatPath = path.join(lockDir, "heartbeat")

          // Atomic mkdir — the POSIX lock primitive
          const created = yield* atomicMkdir(lockDir)

          if (!created) {
            if (!(yield* isStale(lockDir, heartbeatPath, metaPath))) return yield* new NotAcquired()

            // Stale — race for breaker ownership
            const breakerPath = lockDir + ".breaker"

            const claimed = yield* fs.makeDirectory(breakerPath, { mode: 0o700 }).pipe(
              Effect.as(true),
              Effect.catchIf(
                (e) => e.reason._tag === "AlreadyExists",
                () => cleanStaleBreaker(breakerPath),
              ),
              Effect.catchIf(isPathGone, () => Effect.succeed(false)),
              Effect.orDie,
            )

            if (!claimed) return yield* new NotAcquired()

            // We own the breaker — double-check staleness, nuke, recreate
            const recreated = yield* Effect.gen(function* () {
              if (!(yield* isStale(lockDir, heartbeatPath, metaPath))) return false
              yield* forceRemove(lockDir)
              return yield* atomicMkdir(lockDir)
            }).pipe(Effect.ensuring(forceRemove(breakerPath)))

            if (!recreated) return yield* new NotAcquired()
          }

          // We own the lock dir — write heartbeat + meta with exclusive create
          yield* exclusiveWrite(heartbeatPath, "", lockDir, "heartbeat already existed")

          const metaJson = encodeMeta({ token, pid: process.pid, hostname, createdAt: new Date().toISOString() })
          yield* exclusiveWrite(metaPath, metaJson, lockDir, "meta.json already existed")

          return { token, metaPath, heartbeatPath, lockDir } satisfies Handle
        }).pipe(
          Effect.withSpan("EffectFlock.tryAcquire", {
            attributes: { key },
          }),
        )

      // -- retry wrapper (preserves Handle type) --