22 lines
1.4 KiB
Markdown
22 lines
1.4 KiB
Markdown
# Logging structured traces
|
|
|
|
In order to have meaningful and useful log traces, you should follow
|
|
some general guidelines described in the [Project Guidelines](http://doc-internal.cartodb.net/platform/guidelines.html#structured-logging).
|
|
|
|
In this project there is a specific logger in place that takes care of
|
|
format and context of the traces for you. Take a look at [logger.js](https://github.com/CartoDB/Windshaft-cartodb/blob/cf82e1954e2244861e47fce0c2223ee466a5cd64/lib/utils/logger.js)
|
|
(NOTE: that file will be moved soon to a common module).
|
|
|
|
The logger is instantiated as part of the [app startup process](https://github.com/CartoDB/Windshaft-cartodb/blob/cf82e1954e2244861e47fce0c2223ee466a5cd64/app.js#L53),
|
|
then passed to middlewares and other client classes.
|
|
|
|
There are many examples of how to use the logger to generate traces
|
|
throughout the code. Here are a few of them:
|
|
|
|
```js
|
|
lib/api/middlewares/logger.js: res.locals.logger.info({ client_request: req }, 'Incoming request');
|
|
lib/api/middlewares/logger.js: res.on('finish', () => res.locals.logger.info({ server_response: res, status: res.statusCode }, 'Response sent'));
|
|
lib/api/middlewares/profiler.js: logger.info({ stats, duration: stats.response / 1000, duration_ms: stats.response }, 'Request profiling stats');
|
|
lib/api/middlewares/tag.js: res.on('finish', () => logger.info({ tags: res.locals.tags }, 'Request tagged'));
|
|
```
|