Feature Request

Summary:
It would be highly beneficial for go-cron to include functionality to expose metrics in a format that Prometheus can scrape. This would allow users to monitor the performance and health of go-cron jobs within their Prometheus monitoring ecosystem.

Detail:
Currently, go-cron opens an HTTP port that can be used as a health check, as described in the README and implemented in gocron/httpserver.go. Building on this, I propose adding a new endpoint, /metrics, that serves metrics in a Prometheus-compatible format. This would involve metrics such as job execution times, success/failure counts, and other relevant runtime metrics.

Suggested Implementation:

• Extend the HTTP server functionality in gocron/httpserver.go to include a /metrics endpoint.
• Implement a metrics collection system within go-cron that tracks relevant metrics during job execution.
• Format the collected metrics using Prometheus exposition formats, making them available via the /metrics endpoint.

Benefits:

• This feature would enable users to integrate go-cron monitoring with their existing Prometheus setups, providing a unified view of system health and performance.
• It would also allow for alerting on specific conditions related to go-cron jobs, enhancing the ability to respond to issues promptly.

Considerations:

• Care should be taken to ensure that the metrics collection and exposition have minimal impact on the performance of go-cron.
• It would be useful to make the metrics feature configurable, allowing users to enable or disable it as per their requirements.

Thank you for considering this feature request. I believe it would significantly enhance the utility and observability of go-cron in production environments.