Structured Logging

Overview

Structured logging captures logs as machine-readable fields instead of free-form strings.

Why It Matters

• Better filtering and aggregation
• Easier correlation across services
• Cleaner alert rule definitions

flowchart TD
    A[Service Log Event] --> B[JSON Formatter]
    B --> C[Log Collector]
    C --> D[Search Platform]

Practical Example

logger.LogInformation(
    "Order created {@OrderEvent}",
    new
    {
        OrderId = "ord-4021",
        CustomerId = "cust-77",
        Amount = 149.90m,
        Currency = "USD"
    });

Production Example

Multi-service systems commonly emit JSON logs to centralized pipelines, enabling dashboards by endpoint, tenant, and error class.

Common Pitfalls

• Mixing text and JSON formats in the same service
• Inconsistent field naming across teams
• Nested payloads that are difficult to query

Key Takeaways

• Structured logs are easier for tools and humans to analyze.
• Shared field conventions improve cross-team observability.
• Flat, stable schemas simplify long-term operations.