dbbasic-logs

Structured logging with TSV storage and compression.

Philosophy: "Log everything. Query anything. Compress the rest."

Part of the DBBasic family of tiny Python modules.

Features

• Simple API: One-line logging, no setup required
• Structured: TSV format with JSON context
• Unix-Native: Plain text files, grep-able, compressible
• Zero Config: Works out of the box
• Searchable: Built-in search with regex support
• Compressed: Automatic gzip compression for old logs
• Multiple Log Types: Separate files for app, errors, and access logs

Installation

pip install dbbasic-logs

Quick Start

from dbbasic_logs import log

# Basic logging
log.info("User logged in", user_id=42, ip="192.168.1.1")
log.warning("Rate limit approaching", user_id=42, count=95)
log.error("Payment failed", order_id=123, error="Timeout")
log.debug("Cache miss", key="user:42")

# Exception logging with automatic stack traces
try:
    process_payment(order)
except Exception as e:
    log.exception("Payment processing failed", order_id=order.id)
    raise

# HTTP access logging
log.access(
    method="GET",
    path="/api/users",
    status=200,
    duration=0.05,
    ip=request.remote_addr
)

Storage Format

Logs are stored as TSV (tab-separated values) files organized by type and date:

data/logs/
  app/
    2025-10-09.tsv         # Today's application logs
    2025-10-08.tsv.gz      # Yesterday's logs (compressed)
    2025-10-07.tsv.gz      # Older logs (compressed)
  errors/
    2025-10-09.tsv         # Today's error logs with stack traces
    2025-10-08.tsv.gz
  access/
    2025-10-09.tsv         # Today's HTTP access logs
    2025-10-08.tsv.gz

TSV Format

Each log entry is a single line with 4 tab-separated columns:

timestamp   level   message   context

Example:

1696886400  INFO    User logged in  {"user_id":42,"ip":"192.168.1.1"}
1696886401  ERROR   Payment failed  {"order_id":123,"error":"Timeout"}

Querying Logs

Python API

from dbbasic_logs import log

# Search for errors in last 7 days
errors = log.search("ERROR", log_type='errors', days=7)
for error in errors:
    print(f"{error['timestamp']}: {error['message']}")
    print(f"  Context: {error['context']}")

# Find user activity (regex search)
user_logs = log.search(r"user_id.*42", log_type='all', days=30)

# Get recent logs
recent = log.tail('app', lines=100)

# Find slow requests
slow_requests = log.search(r'duration.*[5-9]\.', log_type='access', days=1)

Command Line (Unix Way)

# All errors today
grep ERROR data/logs/app/2025-10-09.tsv

# All errors last 7 days (including compressed)
zgrep ERROR data/logs/app/2025-10-*.tsv*

# Specific user activity
zgrep 'user_id.*42' data/logs/app/*.tsv*

# Count 500 errors
grep "status.*500" data/logs/access/2025-10-09.tsv | wc -l

# Slow requests (> 1 second)
grep "duration.*[1-9]\." data/logs/access/2025-10-09.tsv

# View logs with the included script
./scripts/view-logs.sh tail app 100
./scripts/view-logs.sh search ERROR app 7
./scripts/view-logs.sh today errors
./scripts/view-logs.sh errors 1

Log Rotation & Compression

The included rotation script automatically:

• Compresses yesterday's logs (10:1 compression ratio)
• Deletes old logs based on retention policy
• Keeps errors longer than access logs

Setup Automatic Rotation

# Install to cron (runs daily)
sudo cp scripts/rotate-logs.sh /etc/cron.daily/dbbasic-logs-rotate
sudo chmod +x /etc/cron.daily/dbbasic-logs-rotate

Manual Rotation

./scripts/rotate-logs.sh

Custom Retention Policies

# Set custom retention (in days)
export APP_RETENTION_DAYS=30      # App logs (default: 30)
export ACCESS_RETENTION_DAYS=7    # Access logs (default: 30)
export ERROR_RETENTION_DAYS=90    # Error logs (default: 90)

./scripts/rotate-logs.sh

Configuration

Custom Log Directory

from dbbasic_logs import DBBasicLogger

# Use custom directory
logger = DBBasicLogger(log_dir='/var/log/myapp')
logger.info("Custom location", app="myapp")

Environment Variable

# Set globally via environment
export LOG_DIR=/var/log/myapp

# Now all logs go to /var/log/myapp
python your_app.py

Integration Examples

Flask Application

from flask import Flask, request
from dbbasic_logs import log
import time

app = Flask(__name__)

@app.before_request
def log_request_start():
    request.start_time = time.time()

@app.after_request
def log_request_end(response):
    duration = time.time() - request.start_time

    log.access(
        method=request.method,
        path=request.path,
        status=response.status_code,
        duration=duration,
        ip=request.remote_addr,
        user_agent=request.user_agent.string
    )

    return response

@app.route('/api/users/<user_id>')
def get_user(user_id):
    log.info("Fetching user", user_id=user_id, ip=request.remote_addr)

    try:
        user = User.get(user_id)
        if not user:
            log.warning("User not found", user_id=user_id)
            return {"error": "Not found"}, 404

        return user.to_dict()
    except Exception as e:
        log.exception("Error fetching user", user_id=user_id)
        return {"error": "Internal error"}, 500

Django Middleware

from dbbasic_logs import log
import time

class LoggingMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        start_time = time.time()

        response = self.get_response(request)

        duration = time.time() - start_time
        log.access(
            method=request.method,
            path=request.path,
            status=response.status_code,
            duration=duration,
            ip=request.META.get('REMOTE_ADDR'),
        )

        return response

Background Job Queue

from dbbasic_logs import log

def process_jobs(handlers):
    jobs = get_pending_jobs()
    log.info("Processing jobs", count=len(jobs))

    for job in jobs:
        try:
            log.info("Starting job", job_id=job['id'], type=job['type'])
            start = time.time()

            result = handlers[job['type']](job['payload'])

            duration = time.time() - start
            log.info("Job completed", job_id=job['id'], duration=duration)
        except Exception as e:
            log.exception("Job failed", job_id=job['id'], type=job['type'])

Performance

Benchmarks

Operation	Time	Notes
Write log	0.1ms	Append to file
Search today	0.5s	grep 10MB file
Search compressed	2s	zgrep 1MB file
Tail recent	0.01s	Read last N lines

Storage

Daily Logs	Uncompressed	Compressed	30 Days Total
Low traffic	1MB	100KB	3MB
Medium traffic	10MB	1MB	30MB
High traffic	100MB	10MB	300MB

Even high-traffic sites: < 1GB for 30 days of logs

Comparison to Alternatives

vs. Sentry (Error Tracking SaaS)

Sentry:

• Setup: SDK integration, API keys
• Cost: $29-$299/month
• Features: Grouping, alerts, dashboards
• Privacy: Sends errors to third-party

dbbasic-logs:

• Setup: Import and use
• Cost: $0
• Features: TSV storage, grep search
• Privacy: All local

vs. Python logging + RotatingFileHandler

Python stdlib:

# 8 lines just for config
import logging
from logging.handlers import RotatingFileHandler

handler = RotatingFileHandler('app.log', maxBytes=10000, backupCount=5)
formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
handler.setFormatter(formatter)
logger = logging.getLogger('app')
logger.addHandler(handler)

logger.info("User logged in", extra={'user_id': 42})  # Awkward

dbbasic-logs:

from dbbasic_logs import log

log.info("User logged in", user_id=42)  # Natural

vs. ELK Stack

ELK:

• Setup: Docker compose with 3 services
• Memory: 4GB+ RAM
• Complexity: High

dbbasic-logs:

• Setup: Import
• Memory: 0 (just files)
• Complexity: Low

Design Principles

1. Foundational: All other DBBasic modules use this
2. Simple: One-line logging, no setup
3. Structured: TSV format, queryable
4. Unix-Native: Plain text, grep-able, compressible
5. Zero Config: Works out of the box

Security & Privacy

What NOT to Log

Never log sensitive data:

# BAD - Don't do this
log.info("User logged in", password=password)  # ❌
log.info("Payment", credit_card=card_number)   # ❌

# GOOD - Log safely
log.info("User logged in", user_id=user.id)    # ✓
log.info("Payment", order_id=order.id)         # ✓

Log File Permissions

Protect your logs:

# Restrict access to logs
chmod 700 data/logs
chmod 600 data/logs/*/*.tsv*

Contributing

This module is part of the DBBasic project. Contributions welcome!

• GitHub: https://github.com/askrobots/dbbasic-logs
• Documentation: https://dbbasic.com/logs-spec

License

MIT License - see LICENSE file for details

Credits

Created as part of the DBBasic project - a collection of tiny, composable Python web framework modules.

Philosophy: Keep it simple. Keep it readable. Keep it under 500 lines.