hushlog 0.1.0

Zero-config PII redaction for Python logging

HushLog

Zero-config PII redaction for Python logging.

Features

• Zero-config -- one call to hushlog.patch() and you're done
• Non-invasive -- wraps existing formatters, no logger rewrites needed
• Performant -- pre-compiled regex with heuristic early-exit checks
• Type-safe -- fully typed with PEP 561 py.typed marker
• Python 3.10+ -- supports Python 3.10 through 3.13

Installation

pip install hushlog

Or with uv:

uv add hushlog

Quick Start

import logging
import hushlog

# Configure logging FIRST, then patch
logging.basicConfig(level=logging.INFO)
hushlog.patch()

logger = logging.getLogger(__name__)

logger.info("User email: [e-mail]")
# Output: User email: [EMAIL REDACTED]

logger.info("Card: 4111-1111-1111-1111")
# Output: Card: [CREDIT_CARD REDACTED]

logger.info("SSN: 123-45-6789")
# Output: SSN: [SSN REDACTED]

How It Works

HushLog wraps your existing logging formatters with a RedactingFormatter that scans the final formatted string for PII patterns. It never replaces loggers or handlers -- your existing logger.info() calls remain unchanged. All regex patterns are pre-compiled at import time with lightweight heuristic pre-checks to minimize overhead on the hot logging path.

What Gets Redacted

Pattern	Example	Output	Notes
Email	[e-mail]	[EMAIL REDACTED]	RFC 5322 subset, @ heuristic pre-check
Credit Card	4111-1111-1111-1111	[CREDIT_CARD REDACTED]	Luhn validated, supports spaces/dashes
SSN	123-45-6789	[SSN REDACTED]	Dashed format only, invalid ranges excluded
Phone	[phone]	[PHONE REDACTED]	US NANP, multiple formats

Configuration

Disable specific built-in patterns or add custom ones:

from hushlog import Config

hushlog.patch(Config(
    disable_patterns=frozenset({"phone"}),
    custom_patterns={"internal_id": r"ID-[A-Z]{3}-[0-9]{6}"},
))

Note: The mask_style option for partial masking (e.g., j***@example.com) is planned for v0.2.0.

Teardown

Call unpatch() to remove HushLog's formatter wrappers and restore the original formatters. This is useful for testing or runtime toggling:

hushlog.unpatch()

Calling unpatch() without a prior patch() is safe (no-op). Calling patch() multiple times is also safe (idempotent).

Limitations

• Only handlers present on the root logger at patch() time are wrapped. Handlers added later will not be redacted.
• Named loggers with propagate=False and their own handlers bypass root-level redaction.
• No structured log support yet (structlog/loguru integrations planned for v0.3.0).
• Phone detection is US NANP only.

Planned

IPv4/IPv6 addresses, AWS keys, Stripe keys, GitHub tokens, JWT tokens, partial masking, and more. See the roadmap for details.

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

License

MIT -- see LICENSE for details.