Fixes

Fixes #5179 by @obulat

Description

The frontend k6 load test runs against the local Nuxt app on every CI run. Initially, when the test was added to run against the staging environment, it failed due to CPU limitations. To address this, we temporarily increased the staging CPU from 0.25 vCPU to 2 vCPU. However, our goal is to restore the staging environment to its previous resource levels while still reliably detecting potential memory leaks.

The k6 load tests run agains the locally-ran Nuxt app in the GitHub-hosted CI runners on every CI run, and then again after the PR is merged, against the Nuxt app deployed on staging. The GitHub-hosted CI runners use 4 CPU processor and 16 GB of RAM ¹.

This PR adjusts the k6 test settings to maintain a constant request rate while preventing the tests from overwhelming the staging environment. It uses the constant-arrival-rate executor, which means that the rate of requests per seconds is constant, and does not depend on whether response was received or not.

After experimenting with different configurations, I think the following values will be a good start:

• duration: 4-minute test is ensures that the load test completes within the CI pipeline timeframe, aligning with Playwright tests.
• requests-per-second: I tried to lower this value 4 times, to match the required CPU usage in staging: from 7.28 rps to 1.72 rps. This was achieved by setting the rate for each scenario to 3 per minute. With six scenarios, this configuration results in an overall request rate of approximately 1.72 requests per second.

Here are some statistics from the k6 tests in staging, as well as the last 3 CI runs in this PR:

Deployment

For better testing how the k6 tests catch memory leaks and whether the new values are appropriate, I think the following process should be followed:

1. Merge in the changes reverted in Fix frontend memory leak #4864, and see how the tests go in staging. We should see memory problems, manifested in either in a higher memory consumption in the AWS dashboard, or in the higher request timings/dropped iterations values.
2. Merge in this PR to try to cap the CPU usage at 25% (since 25% of 2 vCPU should be equivalent to 100% of 0.25 vCPU). The values for the k6 tests should improve, but the memory leak should still be detectable.
3. Revert the first change with the memory leak, confirm that the memory and CPU consumptions are within the lower limits of the staging values we want.
4. Reduce the staging task resources.

Testing Instructions

Confirm that the deployment plan makes sense or suggest improvements.
Check the CI report for the load test and see that the requests per minutes are lower, and the test finishes within 4 minutes.

Checklist

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