direct-logger
based on https://github.com/wesleytodd/loggerr
Logger call API is interoperable with pino logger.
Features:
- Synchronous output (great for cli's, browser and tools)
- Levels (built-in and customizable)
- Formatting (built-in and customizable)
-
direct-loggeris dependency free (formatters are not) - Always captures stack trace on error logs
- Tiny filesize
- The
cliformatter🚀
Install
$ yarn add direct-logger
Usage
const { Logger } = require('direct-logger')
const logger = Logger()
logger.error(new Error('My error message'))
// Thu Apr 16 2015 22:05:27 GMT-0500 (CDT) [error] - {"msg":"Error: My error message\n<STACK TRACE>"}
logger.info('Something happened', {
foo: 'info about what happened'
})
// Thu Apr 16 2015 22:05:27 GMT-0500 (CDT) [info] - {"msg":"Something happened","foo":"info about what happened"}Log Levels
Each log level can be directed to a different output stream or disabled entirely. The default levels are as follows:
fatalerror-
warn(default) infodebugtrace
Constants are available for setting and referencing the levels and their streams. These constants are the all uppercase version of the level. Here is an example of setting the log level:
const logger = Logger({
level: Logger.DEBUG
})
logger.debug('Foo')
// Thu Apr 16 2015 22:05:27 GMT-0500 (CDT) [debug] - {"msg":"Foo"}Customize Levels
You can fully customize the levels for your purposes. For example, here
we implement pino compatible levels:
const log = Logger({
level: [ 'trace', 'debug', 'info', 'warn', 'error', 'fatal' ]
})
log.trace('Example trace log')Log Formatting
direct-logger supports formatting via formatter functions. The default
formatter outputs a timestamp, the log level and the messages formatted
as json. But you can provide a custom formatter function with the formatter
options. Formatter functions take three parameters: date, level, data.
Say we want to output the log message with a color based on the level:
const Logger = require('direct-logger')
const chalk = require('chalk')
const logger = Logger({
formatter: (date, level, data) => {
var color
switch (Logger.levels.indexOf(level)) {
case Logger.FATAL:
case Logger.ERROR:
color = chalk.red
break
case Logger.WARN:
color = chalk.yellow
break
case Logger.INFO:
case Logger.DEBUG:
color = chalk.white
break
}
return color(data.msg)
}
})There are a few built-in in formatters:
-
default: Outputs date, level and json -
cli: Outputs the message and json data, colorized and formatted -
bunyan: Compatible format tobunyan -
browser: Relies onconsole.log, so just returns thedata
For these built-in formatters can specify the string name of the formatter for built-in formatters:
const log = Logger({
formatter: 'cli'
})To use the cli formatter you can require it and pass the formatter options:
const log = Logger({
formatter: require('direct-logger/formatters/cli')
})Output Streams
You can output each level to it's own stream. The method is simple, just pass an
array of streams corresponding to each level as the streams option. The simplest
way is to just map over Logger.levels, this is how we set the defaults:
Logger({
streams: Logger.levels.map(function (level, i) {
return i > Logger.WARN ? process.stdin : process.stderr
})
})The most useful reason to specify an output stream to to redirect logs to files. Here is an example of how to do that:
const logfile = fs.createWriteStream('./logs/stdout.log', {
flags: 'a',
encoding: 'utf8'
})
Logger({
streams: Logger.levels.map(() => logfile)
})Redact secrets
const logger = Logger({
secrets: ["1234"],
secretsHideCharsCount: false, // default false
secretsStringSubstition: "***", // used when secretsHideCharsCount is true
secretsRepeatCharSubstition: "*", // used when secretsHideCharsCount is false
})
logger.info("secret is 123454678") // output "secret is ****5678"
logger.addSecret("5678")
logger.secretsHideCharsCount = true
logger.info("secret is 123454678") // output "secret is ***"
logger.deleteSecret("1234")
logger.info("secret is 123454678") // output "secret is 1234***"
const hasSecret = logger.hasSecret("54678") // hasSecret === trueArguments order
Arguments orders are reversible.
// classical
logger.debug("Hello world !", { foo: "bar" })
// pino compatible
logger.debug({ foo: "bar" }, "Hello world !")
// string message can be replaced by object having a `toString` method
logger.debug({ foo: "bar" }, new Error("Here is a message"))
logger.debug(new Error("Here is another message"), { foo: "bar" })Set Level
logger.setLevel("warn")
logger.minLevel("debug")
logger.maxLevel("info")