roz-logs

Structured logging for Python with optional OpenTelemetry (OTLP) export to providers like Seq.

roz-logs is a thin, dependency-free wrapper over the standard library logging module. It gives you:

• Structured fields — pass key=value pairs to any log call, rendered as readable key=value text or as JSON.
• Context binding — log.bind(device="pi-01") returns a child logger that stamps every record with that context.
• One-call setup — configure() installs handlers/formatters and reads sensible defaults from environment variables.
• Opt-in cloud export — set ROZ_LOGS_OTLP_ENDPOINT to ship logs to any OTLP/HTTP collector (Seq, Grafana, an OpenTelemetry Collector, …). With no endpoint set, it logs to the console and has zero heavy dependencies — ideal for offline/embedded use such as the Raspberry Pi card sorter.

Install

pip install roz-logs            # console logging, no extra deps
pip install "roz-logs[otlp]"    # + OpenTelemetry OTLP export

Usage

from roz_logs import configure, get_logger

configure(service_name="card-sorter")        # call once at startup
log = get_logger(__name__)

log.info("sorted card", card="Black Lotus", bin=3)
# 2026-06-24T19:40:00+00:00 INFO     [card-sorter] __main__: sorted card card="Black Lotus" bin=3

job = log.bind(job_id="abc123")               # bound context
job.warning("reject bin full", bin=9)

try:
    risky()
except Exception:
    log.exception("operation failed", op="sort")   # includes traceback

JSON output (great for log shippers):

configure(service_name="card-sorter", json_output=True)
# {"timestamp": "...", "level": "INFO", "service": "card-sorter", "logger": "...", "message": "sorted card", "card": "Black Lotus", "bin": 3}

Configuration

Every configure() argument falls back to an environment variable, so you can deploy without touching code:

ROZ_LOGS_JSON accepts any of 1, true, yes, on (case-insensitive) to switch from the human-readable TextFormatter to the line-delimited JsonFormatter; anything else keeps text output.

OTLP export (shipping to Seq and other collectors)

The core library has zero runtime dependencies and only ever writes to the console. Cloud/collector export is opt-in through the otlp extra, which pulls in the OpenTelemetry SDK and the OTLP/HTTP log exporter:

pip install "roz-logs[otlp]"

Once installed, setting an OTLP endpoint makes configure() attach a second handler (in addition to the console) that batches log records and exports them over OTLP/HTTP:

export ROZ_LOGS_OTLP_ENDPOINT="http://localhost:5341/ingest/otlp/v1/logs"
export ROZ_LOGS_OTLP_HEADERS="X-Seq-ApiKey=<your-api-key>"

Under the hood build_otlp_handler() wires up an OpenTelemetry LoggerProvider (tagged with service.name = your service_name), a BatchLogRecordProcessor, and an OTLPLogExporter pointed at your endpoint, then returns a stdlib logging.Handler bridging the two. Records flow:

log.info(...) → stdlib logging → OTLP LoggingHandler → BatchLogRecordProcessor
             → OTLPLogExporter (HTTP) → Seq / OTel Collector / Grafana / …

For Seq the endpoint is http://<host>:5341/ingest/otlp/v1/logs and the API key travels in a header (X-Seq-ApiKey). Any OTLP/HTTP logs endpoint works the same way.

Graceful degradation: if you request an endpoint but the otlp extra is not installed, roz-logs logs a warning and keeps console logging working rather than crashing — so the same code runs on a constrained device (console only) and a server (console + OTLP) with no changes.

Development

pip install pytest pytest-cov
pytest                        # runs unit tests with a 90% coverage gate

# to exercise the OTLP code paths, install the extra into your test env:
pip install opentelemetry-sdk opentelemetry-exporter-otlp-proto-http

License

MIT