syslog-appender-pro/awesomeorganization.js

Syslog Appender for TCP/TLS/UDP connections

const { hostname } = require('os');
const tcp = require('net').createConnection;
const tls = require('tls').connect;
const udp = require('dgram').createSocket;

// REFERENCES
// https://tools.ietf.org/html/rfc5424
// https://tools.ietf.org/html/rfc5425
// https://tools.ietf.org/html/rfc5426
// https://tools.ietf.org/html/rfc6587

const FACILITIES = {
  LOCAL0: 16,
  LOCAL1: 17,
  LOCAL2: 18,
  LOCAL3: 19,
  LOCAL4: 20,
  LOCAL5: 21,
  LOCAL6: 22,
  LOCAL7: 23,
}
exports.FACILITIES = FACILITIES;

const SEVERITIES = {
  ALERT: 1,
  CRITICAL: 2,
  DEBUG: 7,
  EMERGENCY: 0,
  ERROR: 3,
  INFORMATIONAL: 6,
  NOTICE: 5,
  WARNING: 4,
}
exports.SEVERITIES = SEVERITIES;

const isObject = (value) => {
  return typeof value === 'object' && Array.isArray(value) === false
}

const parseStructuredData = (structuredData) => {
  let result = ''
  for (const id in structuredData) {
    if (isObject(structuredData[id]) === true) {
      result += `[${id}`
      for (const param in structuredData[id]) {
        result += ` ${param}="${structuredData[id][param]}"`
      }
      result += ']'
    }
  }
  return result.length === 0 ? '-' : result
}

const rfc5424 = ({ appName, eol, facility, hostname, message, msgId, procId, severity, structuredData, timestamp }) => {
  if (typeof facility === 'string') {
    facility = FACILITIES[facility.toUpperCase()] ? FACILITIES[facility.toUpperCase()] : FACILITIES.LOCAL0
  }
  if (typeof severity === 'string') {
    severity = SEVERITIES[severity.toUpperCase()] ? SEVERITIES[severity.toUpperCase()] : SEVERITIES.DEBUG
  }
  if (isObject(structuredData) === true) {
    structuredData = parseStructuredData(structuredData)
  }
  const priority = Math.imul(facility, 8) + severity
  return Buffer.from(`<${priority}>1 ${timestamp} ${hostname} ${appName} ${procId} ${msgId} ${structuredData} ${message}${eol}`)
}
exports.rfc5424 = rfc5424;

// sync -> async
const rfc5425 = ({
  defaultAppName,
  defaultEol,
  defaultFacility,
  defaultHostname,
  defaultMsgId,
  defaultProcId,
  defaultSeverity,
  defaultStructuredData,
  ca,
  cert,
  checkServerIdentity,
  family,
  host,
  key,
  port,
}) => {
  return ({
    appName = defaultAppName,
    eol = defaultEol,
    facility = defaultFacility,
    hostname = defaultHostname,
    message,
    msgId = defaultMsgId,
    procId = defaultProcId,
    severity = defaultSeverity,
    structuredData = defaultStructuredData,
    timestamp = new Date().toISOString(),
  }) => {
    return new Promise((resolve, reject) => {
      const options = {
        ca,
        cert,
        family,
        host,
        key,
        port,
      }
      if (typeof checkServerIdentity === 'function') {
        options.checkServerIdentity = checkServerIdentity
      }
      const socket = tls(options)
      socket.once('error', reject)
      socket.once('end', resolve)
      socket.once('connect', () => {
        socket.end(
          rfc5424({
            appName,
            eol,
            facility,
            hostname,
            message,
            msgId,
            procId,
            severity,
            structuredData,
            timestamp,
          })
        )
      })
    })
  }
}
exports.rfc5425 = rfc5425;

// async -> sync
const rfc5426 = ({
  defaultAppName,
  defaultEol,
  defaultFacility,
  defaultHostname,
  defaultMsgId,
  defaultProcId,
  defaultSeverity,
  defaultStructuredData,
  family,
  host,
  port,
}) => {
  return new Promise((resolve, reject) => {
    const options = {
      0: {
        type: 'udp6',
      },
      4: {
        type: 'udp4',
      },
      6: {
        ipv6Only: true,
        type: 'udp6',
      },
    }
    const socket = udp(options[family])
    socket.connect(port, host)
    socket.once('error', reject)
    socket.once('connect', () => {
      resolve(
        ({
          appName = defaultAppName,
          eol = defaultEol,
          facility = defaultFacility,
          hostname = defaultHostname,
          message,
          msgId = defaultMsgId,
          procId = defaultProcId,
          severity = defaultSeverity,
          structuredData = defaultStructuredData,
          timestamp = new Date().toISOString(),
        }) => {
          socket.send(
            rfc5424({
              appName,
              eol,
              facility,
              hostname,
              message,
              msgId,
              procId,
              severity,
              structuredData,
              timestamp,
            })
          )
        }
      )
    })
  })
}
exports.rfc5426 = rfc5426;

// sync -> async
const rfc6587 = ({
  defaultAppName,
  defaultEol,
  defaultFacility,
  defaultHostname,
  defaultMsgId,
  defaultProcId,
  defaultSeverity,
  defaultStructuredData,
  family,
  host,
  port,
}) => {
  return ({
    appName = defaultAppName,
    eol = defaultEol,
    facility = defaultFacility,
    hostname = defaultHostname,
    message,
    msgId = defaultMsgId,
    procId = defaultProcId,
    severity = defaultSeverity,
    structuredData = defaultStructuredData,
    timestamp = new Date().toISOString(),
  }) => {
    return new Promise((resolve, reject) => {
      const socket = tcp({
        family,
        host,
        port,
      })
      socket.once('error', reject)
      socket.once('end', resolve)
      socket.once('connect', () => {
        socket.end(
          rfc5424({
            appName,
            eol,
            facility,
            hostname,
            message,
            msgId,
            procId,
            severity,
            structuredData,
            timestamp,
          })
        )
      })
    })
  }
}
exports.rfc6587 = rfc6587;

const syslog = ({
  ca,
  cert,
  checkServerIdentity,
  defaultAppName = process.argv[process.argv.length - 1],
  defaultEol = '\0',
  defaultFacility = FACILITIES.LOCAL0,
  defaultHostname = hostname(),
  defaultMsgId = '-',
  defaultProcId = process.pid,
  defaultSeverity = SEVERITIES.DEBUG,
  defaultStructuredData = '-',
  host = 'localhost',
  port = 514,
  key,
  protocol = 'tcp',
}) => {
  switch (protocol) {
    case 'tls': {
      return rfc5425({
        ca,
        cert,
        checkServerIdentity,
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 0,
        host,
        hostname,
        key,
        port,
      })
    }
    case 'tls4': {
      return rfc5425({
        ca,
        cert,
        checkServerIdentity,
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 4,
        host,
        hostname,
        key,
        port,
      })
    }
    case 'tls6': {
      return rfc5425({
        ca,
        cert,
        checkServerIdentity,
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 6,
        host,
        hostname,
        key,
        port,
      })
    }
    case 'tcp': {
      return rfc6587({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 0,
        host,
        hostname,
        port,
      })
    }
    case 'tcp4': {
      return rfc6587({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 4,
        host,
        hostname,
        port,
      })
    }
    case 'tcp6': {
      return rfc6587({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 6,
        host,
        hostname,
        port,
      })
    }
    case 'udp': {
      return rfc5426({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 0,
        host,
        hostname,
        port,
      })
    }
    case 'udp4': {
      return rfc5426({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 4,
        host,
        hostname,
        port,
      })
    }
    case 'udp6': {
      return rfc5426({
        defaultAppName,
        defaultEol,
        defaultFacility,
        defaultHostname,
        defaultMsgId,
        defaultProcId,
        defaultSeverity,
        defaultStructuredData,
        family: 6,
        host,
        hostname,
        port,
      })
    }
    default: {
      throw Error('Unsupported protocol')
    }
  }
}
exports.syslog = syslog;