Marc Mintel
5397309103
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41 lines
1.5 KiB
Plaintext
41 lines
1.5 KiB
Plaintext
# Asynchronous Logging
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Asynchronous logging enables the minimum overhead of Pino.
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Asynchronous logging works by buffering log messages and writing them in larger chunks.
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```js
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const pino = require('pino')
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const logger = pino(pino.destination({
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dest: './my-file', // omit for stdout
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minLength: 4096, // Buffer before writing
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sync: false // Asynchronous logging
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}))
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```
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It's always possible to turn on synchronous logging by passing `sync: true`.
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In this mode of operation, log messages are directly written to the
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output stream as the messages are generated with a _blocking_ operation.
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* See [`pino.destination`](/docs/api.md#pino-destination)
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* `pino.destination` is implemented on [`sonic-boom` ⇗](https://github.com/mcollina/sonic-boom).
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### AWS Lambda
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Asynchronous logging is disabled by default on AWS Lambda or any other environment
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that modifies `process.stdout`. If forcefully turned on, we recommend calling `dest.flushSync()` at the end
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of each function execution to avoid losing data.
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## Caveats
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Asynchronous logging has a couple of important caveats:
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* As opposed to the synchronous mode, there is not a one-to-one relationship between
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calls to logging methods (e.g. `logger.info`) and writes to a log file
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* There is a possibility of the most recently buffered log messages being lost
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in case of a system failure, e.g. a power cut.
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See also:
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* [`pino.destination` API](/docs/api.md#pino-destination)
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* [`destination` parameter](/docs/api.md#destination)
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