zc.lockfile
Basic inter-process locks
Decision gist · record as of 2026-08-14
Yes, if you need portable file-based inter-process locking without external dependencies. The package is stable, actively maintained, and has no known vulnerabilities. The aging maintenance status (330 days since last release) is not a concern given the mature, narrow scope of the library. The unclear license treatment warrants a quick review if you have strict licensing requirements, but the ZPL-2.1 is OSI-approved and widely used in the Zope ecosystem.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later; does not support Python 3.7 or 3.8.
- Low friction: pure Python wheel with only setuptools as a runtime dependency.
- Maintenance status is aging—last release was 330 days ago—but the repository remains active with recent commits and no archived status.
License · maintenance · safety
ZPL-2.1 (unclear) — Licensed under ZPL-2.1 (Zope Public License), which is OSI-approved but less common than MIT or Apache 2.0. License treatment is marked unclear; review the license terms if proprietary use or redistribution is planned.
last release 2025-09-18 (330 days) · last repo commit 2025-09-22 · 20 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 3,226,469 downloads/mo, #2,694 on PyPI
Alternatives
Verify before relying
import zc.lockfile
lock = zc.lockfile.LockFile('mylock')
try:
# critical section
pass
finally:
lock.close()- Whether the ZPL-2.1 license is compatible with your project's licensing constraints
- Performance characteristics under high contention or with many concurrent lock attempts
- Behavior on network filesystems or non-POSIX systems beyond Windows and POSIX
What it is and what it does
zc.lockfile is a lightweight library for creating and managing inter-process locks using the filesystem. Rather than locking files themselves, it uses lock files as a coordination mechanism—the actual resource being protected can be any shared state. The library provides a LockFile class that acquires an OS-level lock on a named file; attempting to lock the same file from another process raises LockError. Lock files persist after release and can optionally include process ID and hostname information for debugging in containerized environments.
The package is designed for scenarios where multiple processes need to serialize access to a shared resource without a dedicated lock server. It is commonly used by database implementations (like ZODB file storage) to mediate access to data files. The implementation is portable across Windows and POSIX systems and supports both CPython and PyPy.
Use it for
- Serialize access to a shared database file from multiple worker processes in a multiprocessing application.
- Prevent concurrent writes to a configuration or state file in a distributed system.
- Coordinate startup or initialization across multiple container instances by using a lock file on a shared volume.
- Implement a simple job-locking mechanism to ensure only one instance of a scheduled task runs at a time.
- Mediate access to a shared resource in a legacy system that predates modern concurrency primitives.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need portable file-based inter-process locking without external dependencies.
The package is stable, actively maintained, and has no known vulnerabilities. The aging maintenance status (330 days since last release) is not a concern given the mature, narrow scope of the library. The unclear license treatment warrants a quick review if you have strict licensing requirements, but the ZPL-2.1 is OSI-approved and widely used in the Zope ecosystem.
Install
zc-lockfile on PyPI
Before you install
Low friction: pure Python wheel with only setuptools as a runtime dependency. Maintenance status is aging—last release was 330 days ago—but the repository remains active with recent commits and no archived status.
Requires Python 3.9 or later; does not support Python 3.7 or 3.8.
License in practice
Licensed under ZPL-2.1 (Zope Public License), which is OSI-approved but less common than MIT or Apache 2.0. License treatment is marked unclear; review the license terms if proprietary use or redistribution is planned.
Quickstart
import zc.lockfile
lock = zc.lockfile.LockFile('mylock')
try:
# critical section
pass
finally:
lock.close()Verify before relying
- Whether the ZPL-2.1 license is compatible with your project's licensing constraints
- Performance characteristics under high contention or with many concurrent lock attempts
- Behavior on network filesystems or non-POSIX systems beyond Windows and POSIX
Package facts
| License | ZPL-2.1 unclear |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagesetuptools |
| Maintenance | Aging 330 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 3,226,469 / month, #2,694 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/StableIntended Audience :: DevelopersLicense :: OSI Approved :: Zope Public LicenseNatural Language :: EnglishOperating System :: Microsoft :: WindowsOperating System :: POSIXProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: Software Development |
Evidence: zc_lockfile-4.0-py3-none-any.whl
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See also flufl.lock · locket · pid · portalocker · lockfile · fasteners · filelock · pyodide-lock · PyMySQLLock · kazoo