import { stringify, Column } from "https://deno.land/std@0.170.0/encoding/csv.ts"import { writeAll } from "https://deno.land/std@0.171.0/streams/write_all.ts"
export interface LogOptions { format?: 'csv' | 'json' disableConsoleLogging?: boolean disableFileLogging?: boolean consoleOutput?: 'raw' | 'pretty' logLabel?: string path?: string maxBytes?: number }
enum LogLevels { Debug = 'DEBUG', Info = 'INFO', Warn = 'WARN', Error = 'ERROR'}
export class TinyLogger { #instantiation = getInstantiation() #format: 'csv' | 'json' #consoleOutput: 'raw' | 'pretty' #logLabel: string #path: string #disableConsoleLogging: boolean #disableFileLogging: boolean #encoder = new TextEncoder() #maxBytes: number #byteLength = 0 #currentLogFile = '' #logFileNumber = 0
#logColors: Map<string, string> = new Map( Object.entries( { DEBUG: 'light-blue', INFO: 'cyan', WARN: 'yellow', ERROR: 'red' } ) )
constructor(options: LogOptions) { this.#format = options.format || 'csv' this.#logLabel = options.logLabel || 'log' this.#consoleOutput = options.consoleOutput || 'pretty' this.#path = options.path || './' this.#maxBytes = options.maxBytes || 10485760 this.#disableConsoleLogging = options.disableConsoleLogging || false this.#disableFileLogging = options.disableFileLogging || false this.init() }
private async init() { if (this.#disableConsoleLogging && this.#disableFileLogging) { throw `TinyLogger Error: file logging and console logging cannot both be disabled.` }
if (!isAlphanumeric(this.#logLabel)) { throw 'TinyLogger Error: loglabel contains invalid characters. Label can be alphanumeric characters only.' }
if (!this.#disableFileLogging) { await testFilePath(this.#path) }
if (this.#logLabel !== 'log') { this.#logLabel = `${this.#logLabel}.log` }
const initialFile = this.#format === 'csv' ? `${this.#logLabel}.${this.#instantiation}.csv` : `${this.#logLabel}.${this.#instantiation}.txt`
this.#currentLogFile = this.#path + initialFile }
debug(source: string, message: string) { const data = formatData(this.#format, LogLevels.Debug, source, message)
if (!this.#disableConsoleLogging) { this.logToConsole(LogLevels.Debug, source, message) }
if (!this.#disableFileLogging) { this.writeFile(data) } }
info(source: string, message: string) { const data = formatData(this.#format, LogLevels.Info, source, message)
if (!this.#disableConsoleLogging) { this.logToConsole(LogLevels.Info, source, message) }
if (!this.#disableFileLogging) { this.writeFile(data) } }
warn(source: string, message: string) { const data = formatData(this.#format, LogLevels.Warn, source, message)
if (!this.#disableConsoleLogging) { this.logToConsole(LogLevels.Warn, source, message) }
if (!this.#disableFileLogging) { this.writeFile(data) } }
error(source: string, message: string) { const data = formatData(this.#format, LogLevels.Error, source, message)
if (!this.#disableConsoleLogging) { this.logToConsole(LogLevels.Error, source, message) }
if (!this.#disableFileLogging) { this.writeFile(data) } }
private logToConsole( level: LogLevels, source: string, message: string ) { const time = (new Date()).toISOString() const outputColor = this.#logColors.get(level)
const data = JSON.stringify({ time, [level]: source, message })
switch (this.#consoleOutput) { case 'raw': console.log(`%c${data}`, `color: ${outputColor};`) break
case 'pretty': console.log(`%c[${time}] ${level}: ${source}`, `color: ${outputColor};`) console.log(`%c${message}\n`, `color: light-blue;`) break
} }
private async writeFile(data: string) { const path = this.#path[this.#path.length - 1] === '/' ? this.#path : this.#path + '/'
const newMessageBytes = this.#encoder.encode(data).byteLength this.#byteLength += newMessageBytes
const file = Deno.openSync( this.#currentLogFile, { read: true, write: true, create: true, append: true } )
if (this.#byteLength > this.#maxBytes) { this.#byteLength = 0 this.#logFileNumber++
const nextFileToWrite = this.#format === 'csv' ? `${this.#logLabel}.${this.#instantiation}_${this.#logFileNumber}.csv` : `${this.#logLabel}.${this.#instantiation}_${this.#logFileNumber}.txt`
this.#currentLogFile = path + nextFileToWrite
const nextFile = Deno.openSync( this.#currentLogFile, { read: true, write: true, create: true, append: true } )
await writeAll(nextFile, this.#encoder.encode(data)) nextFile.close() } else { await writeAll(file, this.#encoder.encode(data)) file.close() } }}
function getEol() { const os = Deno.build.os const eol = os === 'windows' ? '\r\n' : '\n' return eol}
function isAlphanumeric(s: string) { return /^[A-Za-z0-9]*$/.test(s);}
function formatData( format: 'csv' | 'json', level: LogLevels, source: string, message: string) { let data: string const time = (new Date()).toISOString()
switch (format) { case 'csv': { const columns: Column = [ 'time', 'level', 'source', 'message' ]
data = stringify( [{ time, level, source, message }], { columns, headers: false } ) } break
case 'json': { data = JSON.stringify({ time, level, source, message }) + getEol() } break }
return data}
async function testFilePath(path: string) { try { await Deno.lstat(path); } catch (err) { if (err instanceof Deno.errors.NotFound) { throw `TinyLogger Error: Invalid Path '${path}'` } throw err; }}
function getInstantiation() { const dateTime = new Date() const dtArray = dateTime.toJSON().split('T')
const time = dtArray[1] const timeSansMiliseconds = time.split('.')[0] const timeForFileName = timeSansMiliseconds.replaceAll(':', '-')
const formattedDateTime = `${dtArray[0]}T${timeForFileName}`
return formattedDateTime}