Getting Started

xk6-otel-gen is a k6 extension that synthesizes OpenTelemetry traces, metrics, and logs from a declarative YAML topology. It lets you model microservice graphs, journeys, and faults without building real services.

journeys:
  checkout:
    weight: 1.0
    steps:
      - service: frontend
        operation: get_index

The extension can send OTLP/gRPC and OTLP/HTTP telemetry to collectors and can also forward k6 output metrics through the otel-gen output.

Features

Feature	Concrete example
Topology DSL	`services.frontend.operations[].calls[]` models service edges
Journey execution	`runJourney("checkout")` creates one synthetic trace
Fault injection	`error_rate_override`, `latency_inflation`, `disconnect`, `crash`
Per-operation signals	`log_events`, `metrics`, `profile` emit structured logs, custom metrics, and flamegraphs
Span links & exemplars	`messaging` edges link producer↔consumer spans; metrics carry `trace_id` / `span_id`
Pyroscope profiles	synthetic flamegraphs with fault-linked incident variants for diff profiling
OTLP egress	gRPC on `localhost:4317` or HTTP on `localhost:4318`; profiles via `profilesEndpoint`
k6 output integration	`--out otel-gen=endpoint=localhost:4317` forwards k6 output
JSON Schema export	`go run ./cmd/xk6-otel-gen-schema > topology.schema.json`
Topology visualization	`go run ./cmd/xk6-otel-gen-viz -input topology.yaml -output topology.html`

Example fault:

faults:
  - target: operation:payment.authorize_card
    kind: error_rate_override
    severity:
      probability: 1.0
      value: 0.10

Next steps

Quick Start — build k6 and run synthetic traffic.
Building — build a custom k6 binary with this extension.
Usage — the JavaScript API.

xk6-otel-gen Quick Start