fix(level): Separate concerns for the "level" parameter

README.md

@@ -76,7 +76,12 @@ logger.info({
 ## Custom Log Levels
 
 As per the Winston documentation, [custom log levels](https://github.com/winstonjs/winston#using-custom-logging-levels) may be used. In order to use such
-levels in LogDNA, [custom levels must be defined](https://github.com/logdna/logger-node#custom-log-levels) for that logger as well.
+levels in LogDNA, [custom levels must be defined](https://github.com/logdna/logger-node#custom-log-levels) for that logger as well. If `levels` is passed to this transport, they
+will **automatically** be configured as custom levels for the LogDNA logger.
+
+Similarly, if no custom winston levels are used, then the Winston [default of "npm" levels](https://github.com/winstonjs/winston#logging-levels) will be automatically configured for LogDNA to understand. 
+
+**NOTE:** The "levels" parameter is in the context of Winston, thus it should be an object where the keys are the level names, and the values are a numeric priority.
 
 ```javascript
   const levels = {
@@ -95,7 +100,6 @@ levels in LogDNA, [custom levels must be defined](https://github.com/logdna/logg
 
   const logdna_options = {
     key: 'abc123'
-  , levels: Object.keys(levels)
   }
   logger.add(new logdnaWinston(logdna_options))
 
@@ -110,6 +114,38 @@ levels in LogDNA, [custom levels must be defined](https://github.com/logdna/logg
   })
 ```
 
+## The `maxLevel` Parameter
+
+Both the Winston logger and the LogDNA logger accept a `level` parameter, but they mean different things:
+
+* For Winston, `level` represents the maximum log level by priority. In other words, anything "higher" in priority number WILL NOT be logged.
+* In LogDNA, `level` represents a default log level which is used in the absence of a level being defined for each log entry. Since Winston always passed a log level, this parameter is not usable in this transport.
+
+To disambiguate the two `level` parameters (even though the LogDNA one cannot be used), this custom transport will accept the `maxLevel` parameter to be used as Winston's `level` parameter. This is **only needed if** `level` has not been defined during Winston's `createLogger` call prior to adding this custom transport.
+
+```js
+const winston = require('winston')
+const logdnaTransport = require('logdna-winston')
+
+const logger = winston.createLogger({
+  level: 'verbose'
+, transports:[new logdnaTransport({key: 'abc123'})]
+})
+logger.silly('This will not be logged')
+logger.verbose('This will be logged')
+
+// ...is the same as this
+ const logger = winston.createLogger({
+  transports:[
+    new logdnaTransport({
+      key: 'abc123'
+    , maxLevel: 'verbose'
+    })
+  ]
+})
+logger.silly('This will not be logged')
+logger.verbose('This will be logged')
+```
 ## Contributors ✨
 
 Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):

index.js

@@ -9,11 +9,32 @@ const pkg = require('./package.json')
  */
 module.exports = class LogDNATransport extends Transport {
   constructor(options) {
-    super(options)
+    const {levels, maxLevel, key, ...opts} = options
+    super({
+      ...opts
+    , levels
+    , level: maxLevel
+    })
 
+    let custom_levels = levels
+    if (!custom_levels) {
+      // Per the winston docs, their 'npm' levels will be used, and those must be
+      // set up as custom levels in LogDNA.
+      // @see https://github.com/winstonjs/winston#logging-levels
+      custom_levels = {
+        error: 0
+      , warn: 1
+      , info: 2
+      , http: 3
+      , verbose: 4
+      , debug: 5
+      , silly: 6
+      }
+    }
     // Create an instance of @logdna/logger
-    this.logger = createLogger(options.key, {
-      ...options
+    this.logger = createLogger(key, {
+      ...opts
+    , levels: Object.keys(custom_levels)
     , UserAgent: `${pkg.name}/${pkg.version}`
     })
   }

test/index.js

@@ -197,7 +197,7 @@ test('Call .log() with a message payload and custom level', (t) => {
   , mac: '9e:a0:f8:20:86:3d'
   , url: 'http://localhost:35870'
   , app: 'LogDNA'
-  , levels: Object.keys(levels)
+  , levels
   }
   logger.add(new logdnaWinston(logdna_options))
 
@@ -303,3 +303,93 @@ test('Error will still be processed if there is no stack trace', (t) => {
   , error
   })
 })
+
+test('If no "levels", then use winston defaults and pass LogDNA custom levels', (t) => {
+  const logger = winston.createLogger()
+
+  const logdna_options = {
+    key: 'abc123'
+  , hostname: 'My-Host'
+  , ip: '192.168.2.100'
+  , mac: '9e:a0:f8:20:86:3d'
+  , url: 'http://localhost:35870'
+  , app: 'LogDNA'
+  , maxLevel: 'silly' // Required for this test since 'info' is the max log level by default
+  }
+  logger.add(new logdnaWinston(logdna_options))
+
+  t.plan(4)
+  t.on('end', async () => {
+    nock.cleanAll()
+  })
+
+  nock(logdna_options.url)
+    .post('/', (body) => {
+      for (const {level} of body.ls) {
+        switch (level) {
+          case 'ERROR':
+          case 'INFO':
+          case 'VERBOSE':
+          case 'SILLY':
+            t.pass(`${level} level received`)
+            continue
+          default:
+            t.fail(`${level} is not configured for this test`)
+        }
+      }
+      return true
+    })
+    .query(() => {
+      return true
+    })
+    .reply(200, 'Ingester response')
+
+  logger.error('This is an error')
+  logger.info('This is an info')
+  logger.verbose('This is verbose, which is supported via LogDNA custom levels')
+  logger.silly('This is silly, which is supported via LogDNA custom levels')
+})
+
+test('Winston is passed "level" when the "maxLevel" param is used', (t) => {
+  const logger = winston.createLogger()
+
+  const logdna_options = {
+    key: 'abc123'
+  , hostname: 'My-Host'
+  , ip: '192.168.2.100'
+  , mac: '9e:a0:f8:20:86:3d'
+  , url: 'http://localhost:35870'
+  , app: 'LogDNA'
+  , maxLevel: 'warn'
+  }
+  logger.add(new logdnaWinston(logdna_options))
+
+  t.plan(2)
+  t.on('end', async () => {
+    nock.cleanAll()
+  })
+
+  nock(logdna_options.url)
+    .post('/', (body) => {
+      for (const {level} of body.ls) {
+        switch (level) {
+          case 'ERROR':
+          case 'WARN':
+            t.pass(`${level} level received`)
+            continue
+          default:
+            t.fail(`${level} is not configured for this test`)
+        }
+      }
+      return true
+    })
+    .query(() => {
+      return true
+    })
+    .reply(200, 'Ingester response')
+
+  logger.error('This error will be logged')
+  logger.warn('This warning will be logged')
+  logger.info('This is an info, but will be ignored due to maxLevel')
+  logger.verbose('This is verbose, but will be ignored due to maxLevel')
+})