Pitometer - Open Source Autonomous Quality Gates

07/06/2019

Imagine releasing software with zero upfront meetings. Imagine a release that was tested and promoted (or rejected) through your pipeline automatically. Imagine being able to mix and match the tools that provide those metrics. Imagine a world where you didn’t constantly argue over release acceptance / quality criteria. Imagine an open source tool that did all of that. Meet Pitometer…

Pitometer is an open source tool which allows you to specify your definitions of software quality in code, pull metrics from anywhere, then automatically grade your software into pass, warning or fail states.

Your pipeline can then leverage that decision to promote or reject the deployment.

Pitometer is a module within the keptn project (more on keptn in future blog posts). However Pitometer can also be used as a standalone tool in any environment, not only cloud native environments.

Simple Example

  • You have an upcoming code deployment.
  • You know the figures you need to hit. The business have signed off on them.
  • You’re using both Prometheus and Dynatrace to monitor various parts of the system.

Criteria 1 - Throughput

  • Measured by: Prometheus
  • Success Criteria: 100 requests per second.

Criteria 2 - Response time

  • Measured by: Dynatrace
  • Success Criteria: Average response time less than 3 seconds.

Translation To Pitometer

Let’s translate the above into Pitometer code.

Crucially, this performance as code specification can be committed to any code repository, just like your source code.

{
  "indicators": [
  {
    "id": "prometheus_throughput",
    "source": "Prometheus",
    "query": "rate(http_requests_total)",
    "grading": {
      "type": "Threshold",
      "thresholds": {
        "lowerWarning": 110,
        "lowerSevere": 100
      },
      "metricScore": 50
    }
  },
  {
    "id": "dynatrace_response_time",
    "source": "Dynatrace",
    "query": {
      "timeseriesId": "com.dynatrace.builtin:service.responsetime",
      "aggregation": "avg"
    },
    "grading": {
        "type": "Threshold",
        "thresholds": {
          "upperSevere": 3000000,
          "upperWarning": 2500000
        },
        "metricScore": 50
      }
  }],
  "objectives": {
    "pass": 90,
    "warning": 75
  }
}

Explanation

We have specified two indicators. The first sources its data from Prometheus by running the rate(http_requests_total) query. Pitometer will then grade the results based on the Threshold grader.

Since we’re using lower thresholds, the results will be evaluated as “are they below the threshold?”.

For example, a throughput value of 112 would be a pass. A throughput value of 109 would be in a warning state. A throughput of 100 or less would mean this indicator is in a fail state.

For thresholds, an indicator that passes gets 100% of the metricScore.

  • An indicator in a warning state = 50% of metricScore.
  • An indicator in a fail state = metricScore value of zero.

The second indicator pulls the average response time data from Dynatrace then evaluates against its thresholds.

  • A response time above 2.5 seconds is in warning state.
  • A response time above 3 seconds is in a severe state.

Both indicators are weighted equally (due to each having a metricScore of 50).

You can adjust the importance of each indicator by assigning different total weights to each metric score.

Outcomes (Objectives)

The final block of code objectives evaluates both indicator results against a threshold.

  • If the total metric score is above 90, the deployment is in a pass state.
  • Between 75 and 90 and the deployment is a warning state.
  • Below 75 and the deployment is in a fail state.

Final Thoughts

  • If you’re using Kubernetes, I highly recommend you use keptn, rather than a standalone implementation of Pitometer.
  • You get all the benefits of Pitometer plus the awesome power of keptn.
  • Pitometer follows the “everything as code” philosophy.
  • No more meetings or arguments about deployment health!
  • Pitometer can assess metrics from any source that is accessible via an API.
  • If you can get the metrics out, Pitometer can evaluate them.

Stay Tuned

If you’d like to know more about keptn or Pitometer, contact me or follow me on LinkedIn.

I’ll be releasing a full working demonstration system of Pitometer soon.

Stay tuned…