flufl.lock
NFS-safe file locking with timeouts for POSIX and Windows
Decision gist · record as of 2026-08-14
Yes. This is a mature, actively maintained library with no known vulnerabilities, low install friction, and a permissive license. Install it if you need cross-platform, NFS-safe file locking with timeout support. The main consideration is tuning the lock lifetime correctly for your use case; if you're unsure whether you need NFS safety specifically, a simpler locking mechanism may suffice.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later; lock lifetime must be chosen carefully to balance between process hangs and data corruption risk.
- Low friction installation with only two lightweight runtime dependencies (atpublic, psutil).
- Actively maintained with a recent release; marked Production/Stable and Mature.
License · maintenance · safety
Apache-2.0 (permissive) — Apache-2.0 is permissive; you can use this in commercial and proprietary projects with minimal restrictions beyond attribution and liability disclaimers.
last release 2026-04-27 (109 days)
0 known vulnerabilities (OSV.dev, 2026-08-14) · 3,168,832 downloads/mo, #2,718 on PyPI
Alternatives
Verify before relying
from flufl.lock import Lock
lock = Lock('/tmp/mylock')
with lock:
# critical section
pass- Whether clock synchronization requirements are critical in practice for typical use cases outside distributed NFS environments.
- Performance characteristics under high contention or with very short lock lifetimes.
What it is and what it does
flufl.lock is a file-based locking library that solves the race-condition problem inherent in NFS file systems by using an atomic link-based algorithm inspired by the O_EXCL flag behavior. Instead of relying on exclusive file creation (which is broken on NFS), it creates a unique temporary file and uses the link(2) system call to atomically establish the lock—a technique that works correctly across network file systems and local filesystems alike.
The library is designed for distributed and multi-process environments where you need to coordinate access to shared resources. It supports lock breaking with configurable timeouts, allowing other processes to forcibly acquire a lock if the holder exceeds its declared lifetime. This prevents permanent deadlocks but requires careful tuning: set the lifetime too long and processes will hang waiting; too short and you risk trampling on active locks and corrupting data. It runs on POSIX systems (Linux, macOS) and Windows, making it suitable for cross-platform applications that must coordinate file access.
Use it for
- Serialize access to shared configuration or data files in a distributed system where multiple hosts mount the same NFS volume.
- Prevent concurrent writes to a shared database or log file in a multi-process web application or job queue.
- Implement a distributed task lock so only one worker process executes a critical operation across a cluster.
- Protect against race conditions in CI/CD pipelines or build systems that run on shared network storage.
- Coordinate resource access in containerized or Kubernetes environments where pods may share persistent volumes.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
This is a mature, actively maintained library with no known vulnerabilities, low install friction, and a permissive license. Install it if you need cross-platform, NFS-safe file locking with timeout support. The main consideration is tuning the lock lifetime correctly for your use case; if you're unsure whether you need NFS safety specifically, a simpler locking mechanism may suffice.
Install
flufl-lock on PyPI
Before you install
Low friction installation with only two lightweight runtime dependencies (atpublic, psutil). Actively maintained with a recent release; marked Production/Stable and Mature.
Requires Python 3.10 or later; lock lifetime must be chosen carefully to balance between process hangs and data corruption risk.
License in practice
Apache-2.0 is permissive; you can use this in commercial and proprietary projects with minimal restrictions beyond attribution and liability disclaimers.
Quickstart
from flufl.lock import Lock
lock = Lock('/tmp/mylock')
with lock:
# critical section
passVerify before relying
- Whether clock synchronization requirements are critical in practice for typical use cases outside distributed NFS environments.
- Performance characteristics under high contention or with very short lock lifetimes.
Package facts
| License | Apache-2.0 permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 2 packagesatpublicpsutil |
| Maintenance | Actively maintained 109 days since the last release |
| First released | |
| Downloads | 3,168,832 / month, #2,718 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableDevelopment Status :: 6 - MatureIntended Audience :: DevelopersLicense :: OSI Approved :: Apache Software LicenseOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIXProgramming Language :: PythonProgramming Language :: Python :: 3Topic :: Software Development :: LibrariesTopic :: Software Development :: Libraries :: Python Modules |
Evidence: flufl_lock-9.1.0-py3-none-any.whl
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See also zc.lockfile · portalocker · lockfile · filelock · locket · redlock · fasteners · flufl.bounce · oslo.concurrency · aiorwlock