BE-006 — Prometheus metrics endpoint

[MaryammAli]

Description

Expose /metrics using prom-client with default process metrics plus HTTP request duration/count by route and status.

Acceptance criteria

• /metrics scrapes successfully; per-route histograms present.

Backlog area: A. Bootstrap & Infrastructure · Scope: BackendAcademy (NestJS REST API + WebSocket server)

[shobhamerabacha-star]

Hey maintainers,

I am interested in working on this issue.
Plan:

1. Implement BE-006 — Prometheus metrics endpoint with explicit require_auth checks, secure state storage, and gas optimization.
2. Add Soroban test cases checking unauthorized invocations, edge values, and state updates.

I can start working on this right away. Please assign!

[esegbueadam-sys]

@esegbueadam-sys has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Hi, maintainer. I would like to work on this issue.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @esegbueadam-sys to this issue.

[Husten150]

@Husten150 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I will like to apply

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Husten150 to this issue.

[drips-wave]

Congratulations, @Husten150! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on September 30, 2026.

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[Husten150]

Write-up: Prometheus metrics endpoint

This issue is already implemented. A full src/metrics/ module exists in
app/backend/ with tests. Recording the evidence so it can be verified and
closed rather than re-implemented.

Endpoint

app/backend/src/metrics/metrics.controller.ts:

@ApiTags("metrics")
@Controller("metrics")
export class MetricsController {
  constructor(private metricsService: MetricsService) {}

  @Get()
  @UseGuards(MetricsGuard)
  async getMetrics(): Promise<string> {
    const registry = this.metricsService.getRegistry();
    if (!registry) throw new InternalServerErrorException("Metrics registry not initialized");
    return await registry.metrics();
  }
}

Routes: GET /metrics and GET /metrics/content-type.

Per-route duration/count

app/backend/src/metrics/metrics.interceptor.ts is bound globally in
app/backend/src/app.module.ts via the APP_INTERCEPTOR token, and
metrics.middleware.ts is applied to * in the same file's configure().

Tests

• app/backend/src/metrics/metrics.controller.int.spec.ts
• app/backend/src/metrics/metrics.service.unit.spec.ts

prom-client is a declared dependency in app/backend/package.json.

Two things to confirm before closing

1. Access control. MetricsGuard restricts /metrics. The issue doesn't
   mention auth, so if scraping is meant to be open on an internal network this
   guard may block Prometheus. Worth an explicit decision.
2. Acceptance criterion is about the BackendAcademy service. This code
   lives in app/backend/. The issue body says "Scope: BackendAcademy
   (NestJS REST API + WebSocket server)", and BackendAcademy/ has no metrics
   module at all. If the intended target is BackendAcademy/, this issue is
   not done — it is done for a different service.

I have not ticked the criteria, because of point 2.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@Husten150's PR #907 was approved and merged by @MaryammAli.

🏆 @Husten150: You earned 40 FoxPoints for this contribution! Your current tier: Builder (1,428 total points). Track your full progress on GrantFox.

👏 Great work, @Husten150! Keep contributing to BlockDash-Studios.

[drips-wave]

This issue has been completed by @Husten150 as part of the Stellar Wave Program's 9th Wave 🥳

😎 @Husten150: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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