JSON

{"type":"Metric","data":{"type":"gauge","contains":"default","tainted":null,"thresholds":[],"submetrics":null},"metric":"vus"}
{"type":"Point","data":{"time":"2017-05-09T14:34:45.625742514+02:00","value":5,"tags":null},"metric":"vus"}
{"type":"Metric","data":{"type":"trend","contains":"time","tainted":null,"thresholds":["avg<1000"],"submetrics":null},"metric":"http_req_duration"}
{"type":"Point","data":{"time":"2017-05-09T14:34:45.239531499+02:00","value":459.865729,"tags":{"group":"::my group::json","method":"GET","status":"200","url":"https://quickpizza.grafana.com/api/tools"}},"metric":"http_req_duration"}

Each line either has information about a metric, or logs a data point (sample) for a metric. Lines consist of three items:

• type - can have the values Metric or Point where Metric means the line is declaring a metric, and Point is an actual data point (sample) for a metric.
• data - is a dictionary that contains lots of stuff, varying depending on the "type" above.
• metric - the name of the metric.

Metric

This line has metadata about a metric. Here, "data" contains the following:

• "type" - the metric type (“gauge”, “rate”, “counter” or “trend”)
• "contains" - information on the type of data collected (can e.g. be “time” for timing metrics)
• "tainted" - has this metric caused a threshold to fail?
• "threshold" - are there any thresholds attached to this metric?
• "submetrics" - any derived metrics created as a result of adding a threshold using tags.

Point

This line has actual data samples. Here, "data" contains these fields:

• "time" - timestamp when the sample was collected
• "value" - the actual data sample; time values are in milliseconds
• "tags" - dictionary with tagname-tagvalue pairs that can be used when filtering results data

Processing JSON output

You can use jq to process the k6 JSON output.

You can quickly create filters to return a particular metric of the JSON file:

bash

Copy

bash Copy

jq '. | select(.type=="Point" and .metric == "http_req_duration" and .data.tags.status >= "200")' myscript-output.json

And calculate an aggregated value of any metric:

bash

Copy

bash Copy

jq '. | select(.type=="Point" and .metric == "http_req_duration" and .data.tags.status >= "200") | .data.value' myscript-output.json | jq -s 'add/length'

bash

Copy

bash Copy

jq '. | select(.type=="Point" and .metric == "http_req_duration" and .data.tags.status >= "200") | .data.value' myscript-output.json | jq -s min

bash

Copy

bash Copy

jq '. | select(.type=="Point" and .metric == "http_req_duration" and .data.tags.status >= "200") | .data.value' myscript-output.json | jq -s max

For more advanced cases, check out the jq Manual

Summary export

If you want to see only the aggregated data, you can export the end-of-test summary to a JSON file. For more details, refer to the handleSummary() topic in the end-of-test summary docs .

Read more

• Metrics

Was this page helpful?

No

Suggest an edit in GitHub

Create a GitHub issue

Email [email protected]

Help and support

Community

Related resources from Grafana Labs

Additional helpful documentation, links, and articles:

24 Sep

Performance testing and observability in Grafana Cloud

Optimize user experiences with Grafana Cloud. Learn real-time insights, performance testing with k6, and continuous validation with Synthetic Monitoring.

60 min

User-centered observability: load testing, real user monitoring, and synthetics

Learn how to use load testing, synthetic monitoring, and real user monitoring (RUM) to understand end users' experience of your apps. Watch on demand.