[backend][observability] No Prometheus /metrics endpoint

[Xhristin3]

Severity

High

Files

app/backend/src/main.ts, app/backend/src/monitoring/metrics.controller.ts (does not exist), monitoring/alert_rules.yml

Description

No /metrics endpoint exposed. Prometheus scraping infra (monitoring/prometheus.yml) points at the backend but there's nothing to scrape. alert_rules.yml alerts reference metrics that aren't being exported.

Acceptance Criteria

• Add MetricsController at GET /metrics that serves Prometheus text format
• Wire default Node metrics + custom business metrics (events.created, payments.completed, notifications.failed, rate_limited.total)
• Scrape interval aligned with monitoring/prometheus.yml

[anonfedora]

I'd like to work on this issue because it aligns with my experience implementing monitoring and observability solutions in backend applications.

I have experience integrating Prometheus metrics, exposing scrape endpoints, defining custom business metrics, and ensuring monitoring configurations align with alerting rules. I'm confident in implementing the /metrics endpoint, wiring both default Node.js and application-specific metrics, and validating the setup against the existing Prometheus infrastructure.

[olufunsoolutayo]

Hello maintainer. I'm interested in this issue because implementing a proper Prometheus metrics endpoint is key to making the backend observable and ensuring existing monitoring and alerting work as intended. I have experience with TypeScript/Node.js backends and production monitoring, and I'm confident implementing the /metrics endpoint, exposing both default Node and custom business metrics, and aligning the implementation with the project's Prometheus configuration and acceptance criteria.

[clintjeff2]

Hello, I have 6 years of experience working on tasks like this and handling similar challenges across backend, frontend, and smart-contract development. I have carefully read and fully understood the task requirements, and I am confident I can deliver a clean, efficient, and well-tested solution promptly. I always ensure high-quality implementation, maintainability, and adherence to best practices.

Pull request in 5 hours.

[grantfox-oss]

🦊 GrantFox — @olufunsoolutayo has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #522)
2. Your PR will be reviewed by the Gatheraa maintainers

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