vast-log-python

Python structured logging library implementing the VAST logging standard, built on structlog + orjson for high performance.

Mirrors the API of vast-log-go.

Features

• VAST standard field naming (_service, _id, _ip, _time, _level, _msg, _file)
• JSON output via orjson (fast, sorted keys)
• Kubernetes Downward API integration
• Custom fields support
• Structured, context-bound logging via structlog

Installation

pip install vast-log

Quick Start

import vast_log

cfg = vast_log.Config(
    service="my-service",
    instance_id="pod-abc123",
    ip="10.0.0.1",
    custom={"region": "us-west-2", "env": "production"},
)

logger = vast_log.new(cfg)

logger.info("service started", port=8080, version="1.0.0")
logger.warning("high memory usage", used_mb=900, limit_mb=1024)
logger.error("database connection failed", db_host="postgres:5432")

Output:

{"_file": "basic.py:14", "_id": "pod-abc123", "_ip": "10.0.0.1", "_level": "INFO", "_msg": "service started", "_service": "my-service", "_time": "2024-01-15T10:30:45.123456Z", "env": "production", "port": 8080, "region": "us-west-2", "version": "1.0.0"}

Kubernetes

import vast_log

# Reads SERVICE_NAME, POD_NAME, POD_IP from environment
cfg = vast_log.from_k8s_env()
logger = vast_log.new(cfg)

K8s Downward API env vars:

Env Var	VAST Field
SERVICE_NAME	_service
POD_NAME	_id
POD_IP	_ip

Log Levels

Level	Description
DEBUG	Local debugging only, not used in production
INFO	Normal operation (default level)
WARNING	Recoverable issues
ERROR	Unrecoverable issues, service still available
CRITICAL	Critical issues causing service unavailability