bunyan-serializer
Version:
a lightweight module to pretty print a bunyan stream.
74 lines (67 loc) • 3.04 kB
JavaScript
/**
* createPrettySerializer is a thunk that takes configuration parameters and returns a bunyan serializer function.
* @param {boolean} options.showName Enables printing the logger name in logs. (false)
* @param {boolean} options.showHostname Enables printing the hostname in logs. (false)
* @param {boolean} options.showPid Enables printing the process id in the logs. (true)
* @param {boolean} options.showTime Enables printing the timestamp in the logs. (true)
* @param {boolean} options.showError Enables printing errors in the logs. (true)
* @param {boolean} options.showSilly Prints additional debug information into the logs. (false)
* @return {bunyanSerializer} Returns a pretty formatting bunyanSerializer function that converts bunyan write input to human readable text.
*/
export default function createPrettySerializer( { showName = false
, showHostname = false
, showPid = true
, showTime = true
, showError = true
, showSilly = false
} = {}) {
/**
* Mapping of bunyan level numbers to log levels
* @type {Object}
*/
const LEVEL_MAP = { 10: 'TRACE'
, 20: 'DEBUG'
, 30: 'INFO'
, 40: 'WARN'
, 50: 'ERROR'
, 60: 'FATAL'
}
/**
* prettySerializer takes arguments from a bunyan WritableStream's write method and formats output in a human readable format.
* @param {...Object} args - args that were passed to WritableStream.prototype.write()
* @return {string} human readable string
*/
return function prettySerializer(...args) {
try {
let [record, ...rest] = args
try {
record = typeof record === 'string' ? JSON.parse(record) : record
} catch(err) {
return `NOPARSE|${record}`
}
const { name, hostname, pid, level, msg, time, v, err } = record
let levelName = level ? LEVEL_MAP[level] : 'UNKNOWN'
let output = `${levelName}`
if(showName && name)
output += `|NAME=${name}`
if(showHostname && hostname)
output += `|HOSTNAME=${hostname}`
if(showPid && pid)
output += `|PID=${pid}`
if(showTime && time)
output += `|${time}`
if(v)
output += `|V=${v}`
output += `|${msg}`
if(showError && err) {
const { message, stack } = err
output += `|ERR=${message}\n${stack}`
}
if(showSilly)
output += `\nSILLY => KEYS=[${Object.keys(record).join(', ')}]`
return output
} catch(err) {
return `INTERNAL|ERR=an error occurred formatting output => ${err.message || err}`
}
}
}