Generate synthetic OpenTelemetry data with otelgen

Fully managed
Self-managed

otelgen is a small Go CLI that generates synthetic OTLP logs, traces and metrics. Use it to send test data to fully managed ClickHouse Observability and explore the results in Search and Chart Explorer.

Prerequisites

You need an existing fully managed ClickHouse Observability service and network access to its managed telemetry endpoint. See the fully managed Getting Started guide.

Install otelgen

Install with Homebrew:

brew install krzko/tap/otelgen

Or install with Go:

go install github.com/krzko/otelgen@latest

Set environment variables

Open your ClickHouse Observability service and go to Team Settings → Managed Telemetry. Copy the OTLP HTTP endpoint and API key.Set the endpoint to its host and port, removing the https:// prefix. For example, https://YOUR_OTEL_ENDPOINT:4318 becomes YOUR_OTEL_ENDPOINT:4318. Do not append a signal path such as /v1/logs.

export OTEL_ENDPOINT='YOUR_OTEL_ENDPOINT:4318'
printf "API key: "
read -r -s OTEL_API_KEY
printf "\n"
export OTEL_API_KEY

The commands below use --protocol http without --insecure, so otelgen connects over HTTPS with certificate verification. Removing https:// from the endpoint argument does not disable TLS. Your managed telemetry API key authenticates each request.

Generate traces

Send a short burst of multi-span traces:

otelgen --otel-exporter-otlp-endpoint "${OTEL_ENDPOINT}" \
  --header "authorization=Bearer ${OTEL_API_KEY}" \
  --protocol http \
  --rate 2 --duration 10 \
  traces multi

--rate is traces per second and --duration is the run length in seconds. Omit --insecure so the connection uses HTTPS with certificate verification.

Generate logs

otelgen --otel-exporter-otlp-endpoint "${OTEL_ENDPOINT}" \
  --header "authorization=Bearer ${OTEL_API_KEY}" \
  --protocol http \
  --rate 2 \
  logs multi --duration 10

Generate metrics

Run the following command to generate metrics, then press Ctrl+C after a few seconds to stop it.

otelgen --otel-exporter-otlp-endpoint "${OTEL_ENDPOINT}" \
  --header "authorization=Bearer ${OTEL_API_KEY}" \
  --protocol http \
  --rate 2 \
  metrics sum

otelgen also supports gauge, histogram, up-down-counter and exponential-histogram subcommands under metrics.

Verify in ClickHouse Observability

In your ClickHouse Observability service, open Search and switch between the Logs and Traces sources to confirm new events. Set the time range to Last 15 minutes and look for the default service name otelgen.Open Chart Explorer, select Metrics, and chart otelgen.metrics.sum to verify metrics ingestion.

otelgen is a small Go CLI that generates synthetic OTLP logs, traces and metrics. Use it to confirm that an existing ClickStack OpenTelemetry collector is accepting data and that events surface in the observability UI.This guide assumes the collector is already running with OTLP endpoints on 4317 (gRPC) and 4318 (HTTP).

Prerequisites

This guide assumes you have completed the Getting Started Guide for ClickHouse Observability — Self-managed and have an OpenTelemetry collector running with the OTLP gRPC (4317) and HTTP (4318) endpoints reachable from the machine you run otelgen on. If you secured the collector with an OTLP_AUTH_TOKEN, keep that value handy.

Install otelgen

Install with Homebrew:

brew install krzko/tap/otelgen

Or install with Go:

go install github.com/krzko/otelgen@latest

Set environment variables

Export the collector endpoint and, if the collector is secured, the auth token:

export OTEL_ENDPOINT=<host>:4317
export OTLP_AUTH_TOKEN=<your_otlp_auth_token>

Use the host and port of your collector. For a collector running on the same machine, this is localhost:4317.

Unsecured collectorThe ClickStack OpenTelemetry collector is unauthenticated by default. If you haven’t followed Securing the collector to set an OTLP_AUTH_TOKEN, skip OTLP_AUTH_TOKEN here and drop the --header flag from the commands below.

Generate traces

Send a short burst of multi-span traces:

otelgen --otel-exporter-otlp-endpoint ${OTEL_ENDPOINT} \
  --header "authorization=${OTLP_AUTH_TOKEN}" \
  --protocol grpc --insecure \
  --rate 2 --duration 10 \
  traces multi

--rate is traces per second and --duration is the run length in seconds. --insecure disables TLS on the gRPC connection, which is needed when pointing otelgen at the collector’s plaintext OTLP port.

Generate logs

otelgen --otel-exporter-otlp-endpoint ${OTEL_ENDPOINT} \
  --header "authorization=${OTLP_AUTH_TOKEN}" \
  --protocol grpc --insecure \
  --rate 2 --duration 10 \
  logs multi

Generate metrics

The metrics subcommands don’t honor --duration. Run the command and press Ctrl+C after a few seconds to stop it.

otelgen --otel-exporter-otlp-endpoint ${OTEL_ENDPOINT} \
  --header "authorization=${OTLP_AUTH_TOKEN}" \
  --protocol grpc --insecure \
  --rate 2 \
  metrics sum

otelgen also supports gauge, histogram, up-down-counter and exponential-histogram subcommands under metrics.

Verify in the observability UI

Open the observability UI from the ClickHouse Cloud console. In the Search view, switch the source between Logs and Traces to confirm new events. Set the time range to Last 15 minutes. Open the Chart Explorer, select Metrics, and chart one of the metric names produced by otelgen (for example otelgen.metrics.sum) to verify metrics ingestion.

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Generate synthetic OpenTelemetry data with otelgen