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    OpenTelemetry async_hooks-based Context Managers

    NPM Published Version Apache License

    This package provides two ContextManager implementations built on APIs from Node.js's async_hooks module. If you're looking for a ContextManager to use in browser environments, consider opentelemetry-context-zone or opentelemetry-context-zone-peer-dep.

    The definition of the ContextManager interface and the problem it solves can be found here.


    Two ContextManager implementations are exported:

    The former should be preferred over the latter as its implementation is substantially simpler than the latter's, and according to Node.js docs,

    While you can create your own implementation [of AsyncLocalStorage] on top of [AsyncHook], AsyncLocalStorage should be preferred as it is a performant and memory safe implementation that involves significant optimizations that are non-obvious to implement.

    AsyncLocalStorage is available in node ^12.17.0 || >= 13.10.0, however AsyncLocalStorageContextManager is not enabled by default for node <14.8.0 because of some important bugfixes which were introduced in v14.8.0 (e.g., nodejs/node#34573).


    It's possible that this package won't track context perfectly when used with certain packages. In particular, it inherits any bugs present in async_hooks. See here for known issues.

    async_hooks is still seeing significant correctness and performance fixes, it's recommended to run the latest Node.js LTS release to benefit from said fixes.

    Prior art

    Context propagation is a big subject when talking about tracing in Node.js. If you want more information about it here are some resources:

    Useful links


    Apache 2.0 - See LICENSE for more information.


    npm i @opentelemetry/context-async-hooks

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    • bogdandrutu
    • dyladan