Support custom levels (#27)

* buildOptions with custom levels

* tests added

* Readme updated

* version updated

* update changelog

* fix typo

* fix levels relationship

* fix comments

* docs

* Apply suggestions from code review

---------

Co-authored-by: Yaser El Dabete Arribas <[email protected]>
Co-authored-by: James Sumners <[email protected]>

Author: 3 people

Readme.md

@@ -178,6 +178,32 @@ This also shows the full structure of a configuration file, which can be loaded
 [tzstring]: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
 [luxon]: https://moment.github.io/luxon/#/zones?id=specifying-a-zone
 
+### Custom levels
+
+Custom [Pino levels](https://github.com/pinojs/pino/blob/HEAD/docs/api.md#opt-customlevels) are supported.
+They must be established through a mapping defined under the `customLevels`
+configuration key. `customLevels` is a hash of hashes. Each key under
+`customLevels` is a custom level name with a value that is a hash with
+keys `level` and `syslogSeverity`. The `level` key maps to the log level number,
+and the `syslogSeverity` key to the name of a spec compliant syslog level:
+"emergency", "alert", "critical", "error", "warning", "notice", "info", or
+"debug".
+
+The following example shows how to add customized levels:
+
+```json
+{
+  "modern": true,
+  "appname": "none",
+  "customLevels": {
+    "customLevel_name": {
+      "level": 70,
+      "syslogSeverity": "alert"
+    }
+  }
+}
+```
+
 ## License
 
 [MIT License](http://jsumners.mit-license.org/)

lib/rfc3164.js

@@ -3,11 +3,11 @@
 const { DateTime } = require('luxon')
 const stringify = require('fast-safe-stringify')
 const through2 = require('through2')
-const utils = require('./utils')
 
 function messageBuilderFactory (options) {
+  const levelToSeverity = options.pinoLevelToSyslogSeverity
   return function (data) {
-    const severity = utils.levelToSeverity(data.level)
+    const severity = levelToSeverity.get(data.level)
     const pri = (8 * options.facility) + severity
     let timestamp = DateTime.fromMillis(data.time, { zone: options.tz }).toFormat('LLL dd HH:mm:ss')
     if (timestamp[4] === '0') {

lib/rfc5424.js

@@ -3,12 +3,12 @@
 const { DateTime } = require('luxon')
 const stringify = require('fast-safe-stringify')
 const through2 = require('through2')
-const utils = require('./utils')
 
 function messageBuilderFactory (options) {
   const version = 1
+  const levelToSeverity = options.pinoLevelToSyslogSeverity
   return function (data) {
-    const severity = utils.levelToSeverity(data.level)
+    const severity = levelToSeverity.get(data.level)
     const pri = (8 * options.facility) + severity
     const tstamp = DateTime.fromMillis(data.time, { zone: options.tz })
       .set({ millisecond: 0 })

lib/transport.js

@@ -3,15 +3,14 @@
 const build = require('pino-abstract-transport')
 const SonicBoom = require('sonic-boom')
 const { Transform, pipeline } = require('stream')
-const { defaults } = require('./utils')
+const { buildOptions } = require('./utils')
 const { messageBuilderFactory: rfc5424 } = require('./rfc5424.js')
 const { messageBuilderFactory: rfc3164 } = require('./rfc3164.js')
 
 module.exports = pinoTransport
 
 function pinoTransport (options) {
-  const opts = Object.assign({}, defaults, options)
-
+  const opts = buildOptions(options)
   const processMessage = opts.modern ? rfc5424(opts) : rfc3164(opts)
 
   let destination

lib/utils.js

@@ -1,5 +1,14 @@
 'use strict'
 
+const pinoLevels = {
+  fatal: 60,
+  error: 50,
+  warn: 40,
+  info: 30,
+  debug: 20,
+  trace: 10
+}
+
 const severity = {
   emergency: 0,
   alert: 1,
@@ -11,31 +20,19 @@ const severity = {
   debug: 7
 }
 
-function levelToSeverity (level) {
-  let result
-  switch (level) {
-    case 10: // pino: trace
-      result = severity.debug
-      break
-    case 20: // pino: debug
-      result = severity.debug
-      break
-    case 30: // pino: info
-      result = severity.info
-      break
-    case 40: // pino: warn
-      result = severity.warning
-      break
-    case 50: // pino: error
-      result = severity.error
-      break
-    case 60: // pino: fatal
-    default:
-      result = severity.critical
-      break
-  }
-  return result
-}
+/**
+ * pinoLevelToSyslogSeverity is used to maintain a relationship between
+ * known or custom pino levels and pino-syslog severity levels.
+ *
+ */
+const pinoLevelToSyslogSeverity = new Map([
+  [pinoLevels.trace, severity.debug],
+  [pinoLevels.debug, severity.debug],
+  [pinoLevels.info, severity.info],
+  [pinoLevels.warn, severity.warning],
+  [pinoLevels.error, severity.error],
+  [pinoLevels.fatal, severity.critical]
+])
 
 const defaults = {
   enablePipelining: true,
@@ -47,11 +44,43 @@ const defaults = {
   messageOnly: false,
   tz: 'UTC',
   newline: false,
-  sync: false
+  sync: false,
+  pinoLevelToSyslogSeverity
+}
+
+/**
+ * Applies user supplied options to override internal defaults.
+ * When the options object contains the `customLevels` property, the custom levels are added to the `pinoLevelToSyslogSeverity`
+ * map along with their transformation into one of the syslog levels.
+ *
+ * When the given severity level does not exist, the default `severity.error` is used.
+ *
+ * @param {*} options
+ * @param {*} args
+ *
+ * @returns {object} Updated options object with any defined custom levels
+ * added to the `pinoLevelToSyslogSeverity` field.
+ */
+function buildOptions (options = {}, args = {}) {
+  const opts = Object.assign({}, defaults, options, args)
+
+  if (options.customLevels == null) {
+    return opts
+  }
+
+  for (const [key, { level, syslogSeverity }] of Object.entries(options.customLevels)) {
+    const sev = severity[syslogSeverity] || severity.error
+
+    pinoLevels[key] = level
+    pinoLevelToSyslogSeverity.set(pinoLevels[key], sev)
+  }
+
+  opts.pinoLevelToSyslogSeverity = pinoLevelToSyslogSeverity
+  return opts
 }
 
 module.exports = {
   severity,
-  levelToSeverity,
+  buildOptions,
   defaults
 }

psyslog.js

@@ -5,7 +5,7 @@ const path = require('path')
 const pump = require('pump')
 const split2 = require('split2')
 const parseJson = require('fast-json-parse')
-const { defaults } = require('./lib/utils')
+const { buildOptions } = require('./lib/utils')
 
 const longOpts = {
   modern: Boolean,
@@ -44,7 +44,7 @@ if (args.config) {
   }
 }
 
-const options = Object.assign({}, defaults, jsonOptions, args)
+const options = buildOptions(jsonOptions, args)
 
 let myTransport
 if (options.modern) {

test/3164.test.js

@@ -202,6 +202,20 @@ test('write synchronously', (t) => {
   psyslog.stdin.write(messages.helloWorld + '\n')
 })
 
+test('sets customLevels', (t) => {
+  t.plan(1)
+  const expected = '<134>Apr  1 16:44:58 MacBook-Pro-3 test[94473]: hello world'
+  const psyslog = spawn('node', [psyslogPath, '-c', configPath('3164', 'appname.json')])
+
+  psyslog.stdout.on('data', (data) => {
+    const msg = data.toString()
+    t.equal(msg, expected)
+    psyslog.kill()
+  })
+
+  psyslog.stdin.write(messages.helloWorld + '\n')
+})
+
 function getConfigPath () {
   const cpath = join.apply(null, [__dirname, 'fixtures', 'configs'].concat(Array.from(arguments)))
   return require(cpath)

test/5424.test.js

@@ -174,6 +174,20 @@ test('uses structured data', (t) => {
   psyslog.stdin.write(messages.helloWorld + '\n')
 })
 
+test('sets customLevels', (t) => {
+  t.plan(1)
+  const expected = '<134>1 2016-04-01T16:44:58Z MacBook-Pro-3 test 94473 - - hello world'
+  const psyslog = spawn('node', [psyslogPath, '-c', configPath('5424', 'custom-level.json')])
+
+  psyslog.stdout.on('data', (data) => {
+    const msg = data.toString()
+    t.equal(msg, expected)
+    psyslog.kill()
+  })
+
+  psyslog.stdin.write(messages.helloWorld + '\n')
+})
+
 function getConfigPath () {
   const cpath = join.apply(null, [__dirname, 'fixtures', 'configs'].concat(Array.from(arguments)))
   return require(cpath)

test/fixtures/configs/3164/custom-level.json

@@ -0,0 +1,8 @@
+{
+  "modern": false,
+  "appname": "test",
+  "messageOnly": true,
+  "customLevels": {
+    "unexpectedCodeBranch": { "level": 70, "syslogSeverity": "alert"}
+  } 
+}

test/fixtures/configs/5424/custom-level.json

@@ -0,0 +1,7 @@
+{
+  "appname": "test",
+  "messageOnly": true,
+  "customLevels": {
+    "unexpectedCodeBranch": { "level": 70, "syslogSeverity": "alert"}
+  } 
+}