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Convenience wrapper for exonware-xwlazy - provides 'import xwlazy' alias

Project description

⚡ xwlazy

Fewer "ModuleNotFoundError" detours. Optional auto-install and deferred imports inside a package scope you control, with import-name → PyPI-name mappings (bs4beautifulsoup4, etc.), PEP 668 awareness, and optional audit outputs.

Company: eXonware.com · Author: eXonware Backend Team · Email: connect@exonware.com

Status Python License Automation

For Python 3.8+, xwlazy can install missing dependencies on first real use and defer heavy imports so startup stays lighter. It is built for library authors who want one-line opt-in per package, not for replacing pinned production installs.


🚀 Quick start

1. Install

pip install exonware-xwlazy
# or
pip install xwlazy

xwlazy itself does not use [lazy] / [full] extras; install it directly (commands above) and use [lazy] / [full] on stack packages that depend on it.

  • On a system interpreter, PEP 668 is respected: no silent installs into externally managed environments.
  • Inside a venv, installs use that environment's pip.

2. Enable for your package (one line in __init__.py)

try:
    from exonware.xwlazy import config_package_lazy_install_enabled
    config_package_lazy_install_enabled(__package__ or "yourorg.yourlib", enabled=True, mode="smart")
except ImportError:
    # xwlazy not installed -> normal behavior (no lazy hook)
    pass

Normal import statements stay as they are. Inside the enabled scope you get lazy install and (when policy allows) lazy loading.

3. Zero-code opt-in (optional)

[project]
keywords = ["xwlazy-enabled"]

After pip install -e ., lazy mode can turn on from project metadata.


✨ What you get

Capability What it does
Lazy install First touch on a missing module can trigger pip install for the mapped package.
Lazy loading Selected imports wait until use when your policy enables it.
Per-package scope Each package opts in; others are unchanged.
Keyword opt-in xwlazy-enabled in pyproject.toml enables without code.
Two-stage behavior Import time: log and defer; use time: install then continue.
Policy / audit Allow/deny lists, lockfile, SBOM hooks, PEP 668 checks.
Persist to project Successful installs can append requirements.txt / pyproject.toml. Use XWLAZY_PERSIST_EXTRAS and XWLAZY_NO_PERSIST to control.

Implementation: src/exonware/xwlazy.py; src/xwlazy.py re-exports. src/_old/ is reference-only and is not shipped as the runtime entry.


🗺️ Built-in mappings

Curated table: src/exonware/xwlazy_external_libs.toml (data/ML, DL, viz, web, formats). Override or extend in your tree if you need custom rows.


📊 Benchmarks vs other lazy-import tools

We run xwlazy next to pipimport, deferred-import, lazy-loader, lazy-imports, pylazyimports, lazi, lazy-imports-lite, etc. See benchmarks/20260209-benchmark competition/README.md.

Latest campaign (Feb 2026, representative numbers):

  • medium_load: ~4.06 ms (xwlazy) vs ~4.54 ms next best in that run.
  • heavy_load / enterprise_load (benchmark scenario names): ~14 ms and ~41 ms with auto-install, isolation, and audit enabled.

Many competitors only defer imports, or assume import name == pip name. xwlazy adds mapping-aware installs, optional lockfile/SBOM, and per-package isolation. See the feature matrix in the benchmark README.

Common footgun without mapping:

You write Pip package Without mapping
import bs4 beautifulsoup4 pip install bs4 often wrong
import yaml PyYAML pip install yaml fails
import sklearn scikit-learn pip install sklearn fails
import cv2 opencv-python pip install cv2 fails
import PIL Pillow pip install PIL fails
import attr attrs wrong package

🎛️ Modes and strategies

Strategy Behavior Typical use
smart Uses manifests + mappings Default
pip Plain pip under the hook Explicit pip semantics
wheel Prefer wheels Wheel-rich envs
cached Reuse resolved candidates Repeat runs

No activation → normal imports, no lazy behavior.

from xwlazy import auto_enable_lazy

auto_enable_lazy("xwsystem", mode="smart")

🔒 Security and production

  • Deny list in xwlazy_external_libs.toml ([deny_list]).
  • Lockfile (opt-in): with auditing, ~/.xwlazy/xwlazy.lock.toml.
  • Persist: writes to project requirements.txt / pyproject.toml unless disabled (XWLAZY_NO_PERSIST=1, XWLAZY_PERSIST_EXTRAS=...).
  • SBOM (opt-in): generate_sbom()~/.xwlazy/xwlazy_sbom.toml when auditing is on.
  • Async I/O (default): background worker for persist/lockfile/audit. XWLAZY_ASYNC_IO=0 forces sync.
  • PEP 668: no installs into externally managed interpreters; use a venv.

Set XWLAZY_AUDIT_ENABLED=1 before import if you want lockfile/SBOM writes. Auditing is off by default.

Production pattern: pin deps, pre-install in images, keep lazy as a safety net if you accept the trade-offs.


🔧 Optional mixins (off by default)

Per-call wrapper API, AST rewrite, and type-stub helpers exist behind env flags. We recommend leaving them off; they add complexity and are easy to miscompose with the core hook.

Feature Env var
Per-call wrapper XWLAZY_PER_CALL_API=1
AST lazy transform XWLAZY_AST_LAZY=1
Type-stub tooling XWLAZY_TYPING_TOOLS=1

Prefer config_package_lazy_install_enabled, auto_enable_lazy, or attach for normal work.


🩹 Troubleshooting

from xwlazy import get_all_stats

stats = get_all_stats()
  • Nothing installs: get_lazy_install_stats("your-package") - check enabled and mode, and allow lists.
  • First import slow: first install cost; pre-install with [full] or warm caches.

📚 Docs and tests

Aligned with docs/GUIDE_01_USAGE.md and monorepo GUIDE_63_README.

python tests/runner.py
# or per layer: python tests/0.core/runner.py, python tests/1.unit/runner.py

🌐 Ecosystem

xwlazy combines deferred imports, optional on-demand install, import-name → PyPI mappings, optional lockfile/SBOM, caching, manifests, and deny lists—broader than “defer import only” helpers.

Standalone use is fine; other XW packages use it for scoped lazy policy and lean base installs.

Downstream Role of xwlazy
XWSystem Optional [lazy] / [full] style activation
XWFormats Heavy format backends loaded on demand
XWStorage / XWData / XWNode Optional backends without pinning everything at install
XWAPI / XWAuth Optional server-side extras behind policy
XW libs with [lazy] Shared mapping-aware install and audit hooks

💜 Made with love

We ship xwlazy the same way we ship xwsystem and the rest of the stack: with attention to DX, docs, and long-term maintainability. Thank you for building with eXonware.

Built with ❤️ by eXonware.com — Revolutionizing Python Development Since 2025


📜 License and links

Apache-2.0 - see LICENSE.

⏱️ Async

Implementation under src/ is synchronous (no async/await); it can still be used alongside async apps at import boundaries.

Built with ❤️ by eXonware.com — Revolutionizing Python Development Since 2025 Version: 1.0.1.70 | Updated: 08-Apr-2026

Built with ❤️ by eXonware.com - Revolutionizing Python Development Since 2025

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