Bunyan and Express

Demonstrates how to set up and use Bunyan with Cloud Logging in a Node.js Express application.

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For detailed documentation that includes this code sample, see the following:

Code sample

Node.js

To learn how to install and use the client library for Logging, see Logging client libraries.

To authenticate to Logging, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

// Imports the Google Cloud client library for Bunyan.
const lb = require('@google-cloud/logging-bunyan');

// Import express module and create an http server.
const express = require('express');

async function startServer() {
  const {logger, mw} = await lb.express.middleware({
    logName: 'samples_express',
  });
  const app = express();

  // Install the logging middleware. This ensures that a Bunyan-style `log`
  // function is available on the `request` object. This should be the very
  // first middleware you attach to your app.
  app.use(mw);

  // Setup an http route and a route handler.
  app.get('/', (req, res) => {
    // `req.log` can be used as a bunyan style log method. All logs generated
    // using `req.log` use the current request context. That is, all logs
    // corresponding to a specific request will be bundled in the Stackdriver
    // UI.
    req.log.info('this is an info log message');
    res.send('hello world');
  });

  const port = process.env.PORT || 8080;

  // `logger` can be used as a global logger, one not correlated to any specific
  // request.
  logger.info({port}, 'bonjour');

  // Start listening on the http server.
  const server = app.listen(port, () => {
    console.log(`http server listening on port ${port}`);
  });

  app.get('/shutdown', (req, res) => {
    res.sendStatus(200);
    server.close();
  });
}

startServer();

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