Virheloki

Virheloki, literally "error log" in Finnish, is a term used in information technology to denote a log that records errors and exceptions occurring in software systems. It is part of the broader logging and observability stack and is commonly used by Finnish-speaking engineering teams. The term focuses on faults and their diagnosis rather than routine operational messages.

A virheloki entry typically includes a timestamp, a severity level, an error code or type, a concise message, and, when available, a stack trace, module name, and contextual identifiers such as request_id or session_id. Logs may be kept as plain text or stored in structured formats like JSON to enable effective indexing and searching in centralized systems.

Purposes include troubleshooting, root cause analysis, and post-incident reviews. Virheloki supports alerting when error rates rise and complements tracing and metrics in assessing application reliability across services and environments.

Implementation considerations include adopting structured logging, standardizing fields across components, log rotation and retention policies, and masking or avoiding sensitive data. Centralizing virheloki in a log-management platform facilitates cross-service correlation and long-term analysis, while being mindful of performance overhead.

Common challenges are format heterogeneity, high data volume, privacy concerns, and the need for appropriate access controls. When integrated with monitoring dashboards and incident response playbooks, virheloki contributes to robust observability practices.

See also: logging, error handling, stack trace, log rotation, observability.