Daniel Ehrenberg | AsyncContext: Observability in JavaScript through TC39 and WinterCG

To measure the performance of distributed applications, it’s useful to see where an operation comes from, chain them together, and build a distributed trace. OpenTelemetry calls these ‘span IDs’. But how do you keep track of the current span in JavaScript? Node.js’s AsyncLocalStorage is one option that can work, but it is missing in some places (e.g., the browser) and has a performance cost associated with it. This talk introduces AsyncContext, a mechanism to make this possible across all JavaScript environments. AsyncContext is being proposed as a standard, in a collaboration between TC39 and WinterCG.
About the speaker:
Daniel Ehrenberg is a software engineer on Bloomberg’s JavaScript Infrastructure and Tooling engineering team. He serves as the Vice President of Ecma International and contributes to Ecma TC39, the JavaScript standards committee. Daniel has dabbled in WebAssembly and web standards as well, while at Bloomberg as well as in previous positions at Igalia, a free software cooperative, and at Google on the V8 team, the JavaScript engine in Chrome.