Structured logging for express.js app in GKE
npm install gc-json-logger-express
!Health
!License
The logger makes use of async_hooks module which is currently experimental. However, the use of async_hooks mechanism was at basic.
``bash
npm install --save gc-json-logger gc-json-logger-express
yarn add gc-json-logger gc-json-logger-express
`
`js
const { Logger, Severity } = require('gc-json-logger');
const { log } = require('gc-json-logger-express');
const express = require('express');
const app = express();
/ Set desired application log level /
Logger.setLevel(Severity.DEBUG);
/ Filter sensitive data or transform log entry /
app.use(
log((_req, _res, entry) => {
const severity = entry.meta.httpRequest?.status >= 500 ? Severity.ERROR : entry.severity;
return { ...entry, severity };
})
);
app.use(express.text());
app.use(express.json());
app.use((req, res) => res.status(500).send(req.body));
app.listen(3000);
`
`bash`
curl -X POST "http://localhost:3000/echo" \
-H "Content-Type: text/plain" \
-d 'Hello world!'
`json`
{
"severity": "INFO",
"timestamp": "2022-01-01T00:00:00.000Z",
"message": "200 POST /echo",
"httpRequest": {
"protocol": "HTTP/1.1",
"requestSize": "141",
"remoteIp": "::ffff:127.0.0.1",
"requestUrl": "http://localhost:3000/echo",
"requestMethod": "POST",
"userAgent": "curl/7.79.1",
"serverIp": "::ffff:127.0.0.1:3000"
},
"logging.googleapis.com/operation": {
"id": "135af3bd-1cde-4b72-92ac-3106e7514714"
}
}
`json``
{
"severity": "ERROR",
"timestamp": "2022-01-01T00:00:00.000Z",
"message": "500 POST /echo (13ms)",
"httpRequest": {
"latency": "13ms",
"responseSize": "258",
"status": 500
},
"logging.googleapis.com/operation": {
"id": "135af3bd-1cde-4b72-92ac-3106e7514714"
},
"meta": {
"request": {
"headers": {
"host": "localhost:3000",
"user-agent": "curl/7.79.1",
"accept": "/",
"content-type": "text/plain",
"content-length": "12"
},
"body": "Hello world!"
},
"response": {
"headers": {
"x-powered-by": "Express",
"content-type": "text/html; charset=utf-8",
"content-length": "12",
"etag": "W/\"c-00hq6RNueFa8QiEjhep5cJRHWAI\""
},
"body": "Hello world!"
}
}
}