logging

The tracing crate is the modern standard for instrumentation in async Rust. It provides structured logging with spans (representing work) and events (point-in-time records). Spans can be nested, creating a tree that represents causality. I instrument

Debugging distributed requests is miserable without a stable request id, so I generate it once at the edge, echo it back via x-request-id, and attach it to every log line with a child logger. I keep this intentionally boring because it delivers 80% of

Custom middleware lets me inspect or modify every request and response. I implement both __init__ (called once at startup) and __call__ (for each request). By storing start time in the request, I can measure total processing time including view and te

Production debugging is about logs that are searchable. Emit JSON with consistent keys (requestid, memberid, duration). Even if you later add Lograge, this structure maps cleanly.

The log crate provides logging macros (error!, warn!, info!, debug!, trace!) that are backend-agnostic. Libraries use log, and applications choose the backend (env_logger, simple_logger, or tracing). This decouples logging from the implementation. I u

If you ever need to hand logs to support, you don’t want secrets in them. Filter params at the framework level; then add custom filters for app-specific fields (API keys, tokens).

Comprehensive request logging provides visibility into API usage patterns, performance bottlenecks, and security incidents. I log structured JSON that includes request method, path, parameters (sanitized to exclude passwords), response status, duratio

Structured logging outputs JSON-formatted log entries for machine parsing. Each log line includes timestamp, level, message, and contextual fields like request_id, user_id, and service. Structured logs enable powerful queries in Elasticsearch through

SLF4J provides a logging facade, Logback implements it efficiently. I use logger levels—TRACE, DEBUG, INFO, WARN, ERROR—to control verbosity. Parameterized logging with {} placeholders improves performance versus string concatenation. MDC (Mapped Diag

Proper logging is critical for production debugging. I configure loggers for different apps and libraries. I use file handlers for persistence and console handlers for development. Log rotation prevents disk fill-up. I set appropriate levels (DEBUG, I

Adding unique request IDs helps trace logs across distributed systems. I generate a UUID for each request and attach it to both the request object and response headers. I also add it to the logging context so all log entries for that request include t

I’ve started using log/slog for services that want structured logs without a heavy dependency. The key is treating the request logger as data: create a base logger with JSON output, then derive a request logger with fields like request_id and path. I