@opentelemetry/scope-async-hooks

OpenTelemetry AsyncHooks-based Scope Manager

This package provides async-hooks based scope manager which is used internally by OpenTelemetry plugins to propagate specific scope between function calls and async operations. It only targets NodeJS since async-hooks is only available there.

What is a ScopeManager ?

The definition and why they exist is available on the readme of the scope-base package.

Implementation in NodeJS

NodeJS has a specific API to track async scope: async-hooks, it allows to track creation of new async operation and their respective parent. This package only handle storing a specific object for a given async hooks context.

Limitations

Even if the API is native to NodeJS, it doesn't cover all possible cases of scope propagation but there is a big effort from the NodeJS team to fix those. That's why we generally advise to be on the latest LTS to benefit from performance and bug fixes.

There are known modules that break scope propagation (some of them are listed there), so it's possible that the scope manager doesn't work with them.

Prior arts

Context propagation is a big subject when talking about tracing in NodeJS, if you want more informations about that here are some resources:

• https://www.npmjs.com/package/continuation-local-storage (which was the old way of doing context propagation)
• Datadog's own implementation for their Javascript tracer: here
• OpenTracing implementation: here
• Discussion about context propagation by the NodeJS diagnostics working group: here

Useful links

• For more information on OpenTelemetry, visit: https://opentelemetry.io/
• For more about OpenTelemetry JavaScript: https://github.com/open-telemetry/opentelemetry-js
• For help or feedback on this project, join us on gitter

License

Apache 2.0 - See LICENSE for more information.

Changelog

0.3.0

Released 2019-12-13

:rocket: (Enhancement)

• opentelemetry-core, opentelemetry-node, opentelemetry-plugin-dns, opentelemetry-plugin-document-load, opentelemetry-plugin-grpc, opentelemetry-plugin-postgres, opentelemetry-plugin-redis, opentelemetry-tracing, opentelemetry-types
  • #569 chore: allow parent span to be null
• opentelemetry-plugin-document-load
  • #546 chore: fixing issue when metric time is 0 in document-load plugin
  • #469 chore: fixing problem with load event and performance for loadend
• opentelemetry-plugin-http, opentelemetry-plugin-https
  • #548 fix(plugin-http): adapt to current @types/node
• Other
  • #510 chore(circleci): remove duplicate compile step
  • #514 ci: enumerate caching paths manually
  • #470 chore: remove examples from lerna packages
• opentelemetry-core, opentelemetry-metrics, opentelemetry-types
  • #507 feat: direct calling of metric instruments
  • #517 chore: update dependencies gts and codecov
  • #497 chore: bump typescript version to ^3.7.2
• opentelemetry-metrics
  • #475 add shutdown method on MetricExporter interface
• opentelemetry-core, opentelemetry-plugin-document-load, opentelemetry-tracing, opentelemetry-web
  • #466 chore: fixing coverage for karma using istanbul

:bug: (Bug Fix)

• opentelemetry-exporter-jaeger
  • #609 Jaeger no flush interval
• opentelemetry-plugin-dns
  • #613 fix(plugin-dns): remove from default plugin list
• opentelemetry-plugin-http
  • #589 fix(plugin-http): correct handling of WHATWG urls
  • #580 fix(plugin-http): http.url attribute
• opentelemetry-shim-opentracing
  • #577 fix: add missing main in package.json
• opentelemetry-exporter-zipkin
  • #526 fix: zipkin-exporter: don't export after shutdown
• opentelemetry-plugin-grpc
  • #487 fix(grpc): use correct supportedVersions
• opentelemetry-core
  • #472 fix(core): add missing semver dependency

:books: (Refine Doc)

• Other
  • #574 chore: add CHANGELOG.md
  • #575 Add exporter guide
  • #534 feat: add redis plugin example
  • #562 chore(web-example): Added a README for the existing example
  • #537 examples(tracing): add multi exporter example
  • #484 chore: update README for new milestones
• opentelemetry-plugin-mongodb-core
  • #564 docs: add usage for mongodb-core plugin #543)
• opentelemetry-metrics
  • #490 chore: update metrics README
• opentelemetry-plugin-redis
  • #551 chore: fix minor typo
• opentelemetry-exporter-prometheus
  • #521 chore: update prometheus exporter readme with usage and links
• opentelemetry-types
  • #512 chore: minor name change
• opentelemetry-plugin-postgres
  • #473 chore(plugin): postgres-pool plugin skeleton

:sparkles: (Feature)

• opentelemetry-core, opentelemetry-exporter-collector
  • #552 Collector exporter
• opentelemetry-node, opentelemetry-plugin-mysql
  • #525 feat: mysql support
• opentelemetry-plugin-redis
  • #503 feat(plugin): implement redis plugin
• opentelemetry-plugin-mongodb-core
  • #205 feat: add mongodb plugin
• opentelemetry-exporter-prometheus
  • #483 feat: Add prometheus exporter
• opentelemetry-metrics
  • #500 feat: add ConsoleMetricExporter
  • #468 feat: validate metric names
• opentelemetry-scope-zone-peer-dep, opentelemetry-scope-zone, opentelemetry-web
  • #461 feat(scope-zone): new scope manager to support async operations in web
• opentelemetry-core, opentelemetry-plugin-document-load
  • #477 feat(traceparent): setting parent span from server
• opentelemetry-core, opentelemetry-metrics, opentelemetry-types
  • #463 feat: implement labelset
• opentelemetry-metrics, opentelemetry-types
  • #437 feat(metrics): add registerMetric and getMetrics