Logging

Logging is via the standard env_logger crate. Control verbosity with RUST_LOG:

RUST_LOG=info   ./target/release/datapress-duckdb
RUST_LOG=debug  ./target/release/datapress-datafusion
RUST_LOG=warn,datapress_core=debug ./target/release/datapress-duckdb

If unset, logging is effectively off — set at least RUST_LOG=info in production.

Request log format

Every HTTP request emits one line via actix's Logger middleware:

%a "%r" %s %b bytes %Dms

Token	Meaning
%a	Remote IP
%r	First line of request (method + path + version)
%s	Response status
%b	Response size in bytes
%D	Time-to-respond in milliseconds

Example:

INFO  actix_web::middleware::logger 10.0.0.42 "POST /api/v1/datasets/accidents/query HTTP/1.1" 200 81234 bytes 12ms

Startup log

On boot, DataPress logs:

• The bind address (e.g. Listening on http://0.0.0.0:8080).
• The worker count.
• The active backend.
• The full route table (versioned + legacy + probes).
• shutdown_timeout_secs and request_timeout_ms settings.

This is invaluable when debugging "why doesn't /foo work?" — the answer is usually right there in the route table.

Trade-offs

• The logger middleware adds ~1 µs per request; negligible at any realistic QPS.
• Logging at debug is noisy on hot paths (per-batch logs from the DataFusion scan). Use it for development only.