structured-logging

README

Structured Logging & Prometheus Example

This example demonstrates how to implement Industry Standard Observability in Trellis applications using:

1. log/slog: Go's standard library for structured JSON logging.
2. prometheus: Metrics collection for monitoring.
3. Graceful Shutdown: Proper handling of SIGINT (Ctrl+C) to ensure cleanup.

Usage

Run the example:

go run ./examples/structured-logging

The flow will start and log events to stdout in JSON format.

Cancellation

You can cancel the execution at any time by pressing Ctrl+C. The application handles the intersection signal, cancels the context, and shuts down gracefully.

# JSON Output
{"time":"...","level":"INFO","msg":"received interrupt signal, shutting down..."}

Verifying Metrics

The application exposes a Prometheus metrics endpoint on port :2112.

While the application is running (or after it finishes, as the server stays alive until a second Ctrl+C), check the metrics:

curl http://localhost:2112/metrics | grep trellis

Expected Output:

# HELP trellis_node_visits_total Total number of node visits
# TYPE trellis_node_visits_total counter
trellis_node_visits_total{node_id="start"} 1