May 2024 Summaries

We monitored our Node service with OpenTelemetry and sent the data to a Coralogix dashboard, and with a little digging found an issue that was causing over a month of latency on all our tasks. A mysterious re-authentication request for security credentials was happening more than once, which we were able to identify by analyzing the traces in detail. We made a small change to save the results of our authentication call locally, obviating repeated requests, and this resulted in a measured drop in the time of housekeeping tasks. The 40ms average reduction in execution time may seem like little, but it translates into significant savings on infrastructure costs over time. Observability tools like OpenTelemetry provide visibility to understand and improve systems in ways we hadn't anticipated, reducing the unknown unknowns and enabling us to catch issues before they cause problems.

The text discusses writing a Playwright check to verify API responses in a user-first manner, focusing on interacting with the UI as a user would, while also intercepting and analyzing the network layer. The example project involves a website that polls an API endpoint upon submitting a form, and the test uses the `page.waitForResponse` method to inspect the response bodies and ensure they match the expected values. The implementation includes filtering out unwanted responses, checking response bodies for specific criteria, and returning the response object once it meets the conditions. The test is run using Playwright's end-to-end testing framework, and the results are logged to verify that the correct API response is being captured.