snapshot-restore-py
Runtime Hooks for AWS Lambda SnapStart - Python
Decision gist · record as of 2026-08-14
Yes, if you are using AWS Lambda SnapStart with Python. The library is already pre-installed in Lambda runtimes, so you only need to add it to local development dependencies for testing. It has no external dependencies, a permissive license, and solves a specific optimization problem. Maintenance is dormant but the API is stable and the scope is narrow, so active updates are not critical.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9+.
- Hooks registered in files not imported at the top level of your Lambda handler will be ignored; ensure all hook imports occur before lambda_handler execution.
- Low friction: pure Python wheel with no runtime dependencies.
License · maintenance · safety
Apache License 2.0 (permissive) — Apache License 2.0 (permissive) allows commercial use, modification, and distribution with minimal restrictions—suitable for most projects.
last release 2024-11-13 (639 days) · last repo commit 2024-11-18 · 11 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 2,681,307 downloads/mo, #2,943 on PyPI
Alternatives
Verify before relying
from snapshot_restore_py import register_before_snapshot, register_after_restore
@register_before_snapshot
def setup():
# initialization code
pass
@register_after_restore
def restore():
# post-restore code
pass- Whether the pre-installed version in Lambda runtime matches the PyPI release version and how version mismatches are handled.
- Performance impact of hook registration and execution order on Lambda cold-start times.
- Compatibility with Lambda extensions or other SnapStart-related tooling.
What it is and what it does
Snapshot Restore for Python is a lightweight library that lets you hook into AWS Lambda's SnapStart lifecycle by registering code to run before a snapshot is captured and after it is restored. It provides two decorators (`@register_before_snapshot` and `@register_after_restore`) and corresponding function-based registration methods to control initialization and cleanup around snapshot boundaries. The library has no runtime dependencies and is already bundled in Lambda runtime environments, making it a zero-friction addition to SnapStart-enabled functions.
The main use case is optimizing Lambda cold starts by deferring expensive initialization (database connections, external API calls, resource setup) until after a snapshot is restored, rather than on every invocation. BeforeSnapshot hooks run in reverse registration order; AfterRestore hooks run in registration order. Hooks must be registered at module level to be recognized; registering them inside the handler or in unimported files will be silently ignored.
Use it for
- Initialize database connections or connection pools after snapshot restore to avoid stale connections.
- Warm up external API clients or SDKs after restore to ensure fresh authentication and state.
- Clean up temporary resources or close file handles before snapshot to prevent state corruption.
- Establish logging or monitoring context after restore for accurate request tracing.
- Reload configuration or environment-specific settings after restore in multi-environment deployments.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you are using AWS Lambda SnapStart with Python.
The library is already pre-installed in Lambda runtimes, so you only need to add it to local development dependencies for testing. It has no external dependencies, a permissive license, and solves a specific optimization problem. Maintenance is dormant but the API is stable and the scope is narrow, so active updates are not critical.
Install
snapshot-restore-py on PyPI
Before you install
Low friction: pure Python wheel with no runtime dependencies. Dormant maintenance status (last commit 2024-11-18, no updates since initial release 2024-11-13), but the library is pre-installed in AWS Lambda runtime environments, so local installation is primarily for development and testing.
Requires Python 3.9+. Hooks registered in files not imported at the top level of your Lambda handler will be ignored; ensure all hook imports occur before lambda_handler execution.
License in practice
Apache License 2.0 (permissive) allows commercial use, modification, and distribution with minimal restrictions—suitable for most projects.
Quickstart
from snapshot_restore_py import register_before_snapshot, register_after_restore
@register_before_snapshot
def setup():
# initialization code
pass
@register_after_restore
def restore():
# post-restore code
passVerify before relying
- Whether the pre-installed version in Lambda runtime matches the PyPI release version and how version mismatches are handled.
- Performance impact of hook registration and execution order on Lambda cold-start times.
- Compatibility with Lambda extensions or other SnapStart-related tooling.
Package facts
| License | Apache License 2.0 permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Dormant 639 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 2,681,307 / month, #2,943 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 :: Apache Software LicenseNatural Language :: EnglishOperating System :: OS IndependentProgramming Language :: Python :: 3.12Programming Language :: Python :: 3.13 |
Evidence: snapshot_restore_py-1.0.0-py3-none-any.whl
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