otlpeek exporter

Overview

otlpeek is an OpenTelemetry exporter that lets you peek into your otlp streams.

Problem statement

Thanks to various text exposition formats, you can test metrics easily, both manually and programatically.

This is not quite the case with otlp data.

As of today, I could not find an opentelemetry-contrib exporter to solve this in a compact way.

Alternatives include deploying a proper tracing solution, but that might be a too much overhead in CI/CD pipelines, or for quick local testing.

Features

otlpeek can be built into custom OpenTelemetry Collector distributions and when it's added to metrics, logs, or traces pipelines, it will a expose

• a high level overview at /
• the last 100 entries by resource groups at /metrics, /logs, /traces in JSON format

Overview:

otlpeek - Look into otlp streams
Last activity: 2025-06-19 10:14:06

Summary:
  Traces:  12 entries  (browse: /traces)
  Metrics: 7 entries  (browse: /metrics)
  Logs:    5 entries  (browse: /logs)

Use /traces, /metrics, or /logs to view raw gRPC messages in JSON format.

Example /traces endpoint:

{
  "count": 1,
  "data": {
    "map[service.name:simple-service-2]": [
      {
        "resource": {
          "attributes": {
            "service.name": "simple-service-2"
          }
        },
        "scopeSpans": [
          {
            "scope": {
              "name": "",
              "version": ""
            },
            "spans": [
              {
                "attributes": {
                  "http.method": "GET",
                  "http.route": "/api/users",
                  "http.status_code": 500
                },
                "endTimeUnixNano": 1664827201000000000,
                "kind": "Server",
                "name": "GET /api/users",
                "parentSpanId": "",
                "spanId": "",
                "startTimeUnixNano": 1664827200000000000,
                "status": {
                  "code": "Ok",
                  "message": ""
                },
                "traceId": ""
              }
            ]
          }
        ],
        "timestamp": "2025-06-19T14:24:50.22939118+02:00"
      }
    ]
  },
  "type": "traces"
}

Trying it out

You can build the custom OpenTelemetry Collector with the otlpeek exporter using:

ocb --config builder-config.yaml

Then run it:

dist/otlpeek --config=cmd/config.yaml

Alternatively, you can also built it into a Docker image via this Dockerfile.

You can also drop it into any Kubernetes cluster via this example manifest.