[Ret2Hell]

Summary by CodeRabbit

• New Features

  • OpenTelemetry tracing with graceful tracer shutdown and request-level spans
  • Prometheus metrics endpoint (/metrics) exposing ingestion, rejection, deduplication, latency, batch size, and error metrics
  • Instrumentation across the ingestion flow to emit per-batch and per-event metrics

• Chores

  • Added OTLP exporter endpoint configuration (OTEL_EXPORTER_OTLP_ENDPOINT)
  • Dependency updates to support tracing and metrics features

[coderabbitai]

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Free

Run ID: 9d555fec-174f-47f7-a822-7f7b53d9498e

📥 Commits

Reviewing files that changed from the base of the PR and between 76eed6d and 5a10422.

📒 Files selected for processing (1)

• internal/observability/tracing.go

🚧 Files skipped from review as they are similar to previous changes (1)

• internal/observability/tracing.go

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📝 Walkthrough

Walkthrough

Adds OpenTelemetry tracing and Prometheus metrics: new OTLP endpoint config, tracer initialization and shutdown, a Prometheus IngestMetrics type, wiring of metrics/tracing into server and handler (including /metrics endpoint), and dependency updates.

Changes

Cohort / File(s)	Summary
Configuration & Modules /.env.example, go.mod, internal/config/config.go	Adds OTEL_EXPORTER_OTLP_ENDPOINT to example env, exposes OTelEndpoint in IngestConfig, and updates go.mod to include OpenTelemetry and Prometheus-related dependencies.
Observability Core internal/observability/metrics.go, internal/observability/tracing.go	Adds IngestMetrics (Prometheus counters/histograms) and NewIngestMetrics(), and adds InitTracer(ctx, serviceName, otlpEndpoint) (func(), error) to initialize an OTLP HTTP exporter and set the global tracer provider.
Server & Handler Integration cmd/ingest/main.go, internal/server/server.go, internal/server/handler.go	Initializes tracer at startup with shutdown, creates IngestMetrics, updates NewServer and NewIngestHandler signatures to accept metrics, wires metrics and tracing into request handling, and exposes the /metrics endpoint.

Sequence Diagram

sequenceDiagram
    participant C as Client
    participant S as Server (Fiber)
    participant H as IngestHandler
    participant T as Tracer (OTel)
    participant M as IngestMetrics (Prometheus)
    participant P as Redpanda Producer
    participant R as Prometheus (scraper)

    C->>S: POST /events
    S->>H: forward request
    H->>T: Start span (ctx)
    T-->>H: span context
    H->>M: Observe BatchSize
    alt validation fails
        H->>M: Increment EventsRejected(reason)
        H-->>C: 4xx
    else validation passes
        H->>H: dedup checks
        alt dedup error
            H->>M: Increment DedupErrors
        else duplicate
            H->>M: Increment EventsDeduplicated
        end
        H->>P: Produce events
        alt produce fails
            H->>M: Increment ProduceErrors
            H-->>C: 5xx
        else produce succeeds
            H->>M: Increment EventsIngested (per-site)
            H->>M: Observe IngestLatency
            H-->>C: 2xx
        end
    end
    H->>T: End span
    R->>M: Scrape /metrics

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐇 I traced each hop and counted each cheer,
Buckets and counters make metrics clear,
I start a span, then watch them grow,
Prometheus hums, OTLP flows,
Hop-hop—observability in gear!

📝 Coding Plan

• Generate coding plan for human review comments

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Note

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud