@5app/logger 中文文档教程
logger
在 prod 中输出 json 并在 dev 中输出漂亮消息的简单控制台记录
Usage
npm install --save @5app/logger
const logger = require('@5app/logger');
logger.info('An email was sent', {
email: 'customer@5app.com',
template: 'template1',
});
logger.error(new Error('Unknown playlist 123'));
Options
器 可以选择使用以下环境变量自定义记录器：
LOGS_FORMAT: if set tojson, the logger will log messages in json format instead of pretty messages (default behaviour).LOGS_LEVEL: minimum logging level, by default it will bedebug. Accepted values are'debug','info','warn', and'error'TAG: release tag (e.g. docker image tag) to be added to the log messages
Logging levels
日志记录级别（从低到高优先级）：'debug', “信息”、“警告” 和 “错误”。 记录器提供具有以下签名的记录函数：logger.
下面是如何使用记录器的示例：
logger.error('An error happened', new ApiError('The api call failed', 404)); // will log the message, the error message, the stack trace, and the statusCode error property
logger.warn('Be warned', {a: 1, b: Date.now(), c: 'some string'});
logger.info('An event happened', {a: 1, b: Date.now(), c: 'some string'});
logger.debug('A minor operation', {a: 1, b: Date.now(), c: 'some string'});
Fetching context dynamically
除了提供上下文对象外，您也可以使用 logger.addContext 提供一个函数，该函数将在每个日志上调用以获取上下文对象。
如果您使用 async_hooks 或 cls-hooked 以类似于线程本地存储的方式存储请求元数据。
例如，您可以执行以下操作，而不必将 correlationId 显式传递给每个日志：
const asyncLocalStorage = new AsyncLocalStorage();
expressApp.use((req, res, next) {
const correlationId = req.get('X-Correlation-Id') || uuidV4();
asyncLocalStorage.run({correlationId}, () => next());
});
logger.addContext(() => asyncLocalStorage.getStore());
logger.info('User profile updated', {userId: 1234});
输出将如下所示：
{"level":"info","timestamp":"2021-02-23T17:55:43.011Z","correlationId":"12bf5b37-e0b8-56e0-8dcf-dc8c4aefc123","userId":1234}
logger
Simple console logger that outputs json in prod and pretty messages on dev
Usage
npm install --save @5app/logger
const logger = require('@5app/logger');
logger.info('An email was sent', {
email: 'customer@5app.com',
template: 'template1',
});
logger.error(new Error('Unknown playlist 123'));
Options
The logger can optionally be customised using the following environment variables:
LOGS_FORMAT: if set tojson, the logger will log messages in json format instead of pretty messages (default behaviour).LOGS_LEVEL: minimum logging level, by default it will bedebug. Accepted values are'debug','info','warn', and'error'TAG: release tag (e.g. docker image tag) to be added to the log messages
Logging levels
Logging levels are (from lower to higher priority): 'debug', 'info', 'warn', and 'error'. The logger provides the logging functions with the following signatures: logger.<level>(message, objectOrError)
Here is an example of how the logger can be used:
logger.error('An error happened', new ApiError('The api call failed', 404)); // will log the message, the error message, the stack trace, and the statusCode error property
logger.warn('Be warned', {a: 1, b: Date.now(), c: 'some string'});
logger.info('An event happened', {a: 1, b: Date.now(), c: 'some string'});
logger.debug('A minor operation', {a: 1, b: Date.now(), c: 'some string'});
Fetching context dynamically
In addition to providing a context object, you can also use logger.addContext to provide a function which will be called on every log to get a context object.
This can be helpful if you are using async_hooks or cls-hooked to store request metadata similarly to thread-local storage.
For instance, you can do the following without having to explicitly pass the correlationId to each log:
const asyncLocalStorage = new AsyncLocalStorage();
expressApp.use((req, res, next) {
const correlationId = req.get('X-Correlation-Id') || uuidV4();
asyncLocalStorage.run({correlationId}, () => next());
});
logger.addContext(() => asyncLocalStorage.getStore());
logger.info('User profile updated', {userId: 1234});
And the output will look like:
{"level":"info","timestamp":"2021-02-23T17:55:43.011Z","correlationId":"12bf5b37-e0b8-56e0-8dcf-dc8c4aefc123","userId":1234}
