The prometheus_metrics function within the mock-jutsu library is a specialized tool designed to generate high-fidelity Prometheus text exposition data. This function is essential for developers who need to simulate observability telemetry without the overhead of deploying and configuring live exporters or sidecars. By producing authentic mock data that strictly adheres to the Prometheus text-based format, the utility enables the seamless testing of monitoring pipelines, scraping intervals, and data visualization layers. The output includes a sophisticated mix of process-level CPU and memory statistics, Go runtime metrics, and detailed HTTP request telemetry, ensuring a comprehensive representation of a modern cloud-native application.
Technically, the prometheus_metrics function follows the standard Prometheus exposition format, including necessary HELP and TYPE metadata for each metric. It generates complex HTTP counters categorized by method, path, and status code, alongside histograms that utilize monotonic buckets where the +Inf bucket correctly matches the total observation count. This attention to detail ensures that the test data is functionally indistinguishable from real-world metrics, allowing for the validation of complex PromQL queries and alerting rules. Whether integrated via the Python SDK using jutsu.generate('prometheus_metrics') or invoked through the mock-jutsu CLI, the resulting data maintains the structural integrity required by Prometheus-compatible scrapers.
The primary benefit of using mock-jutsu for metric generation is the ability to conduct rigorous integration testing and performance benchmarking. SREs and DevOps engineers can use the JMeter function syntax, ${__mockjutsu(prometheus_metrics,)}, to inject dynamic telemetry into load testing scripts, simulating how monitoring systems behave under high-stress conditions. This approach is invaluable for verifying Grafana dashboard configurations and ensuring that alert thresholds are properly tuned before moving to production. By providing realistic, repeatable test data, this function reduces infrastructure costs and accelerates the development lifecycle, allowing teams to build more resilient observability stacks with confidence.
mockjutsu generate prometheus_metricsmockjutsu bulk prometheus_metrics --count 10mockjutsu export prometheus_metrics --count 10 --format jsonmockjutsu export prometheus_metrics --count 10 --format csvmockjutsu export prometheus_metrics --count 10 --format sqlfrom mockjutsu import jutsujutsu.generate('prometheus_metrics')jutsu.bulk('prometheus_metrics', count=10)jutsu.template(['prometheus_metrics'], count=5)${__mockjutsu_prometheus(prometheus_metrics)}# JMeter Function: __mockjutsu_prometheus# Parameter 1: prometheus_metrics# Parameter 2: (not required for this function)GET /generate/prometheus_metrics# → {"type":"prometheus_metrics","result":"...","status":"ok"}GET /bulk/prometheus_metrics?count=10POST /template {"types":["prometheus_metrics"],"count":1}