feat: support custom raw logger

src/internal.ts

@@ -2,4 +2,4 @@
 // and only meant for consumption by Netlify Teams.
 // While we try to adhere to semver, this file is not considered part of the public API.
 
-export { systemLogger, LogLevel } from './lib/system_logger.js'
+export { systemLogger, LogLevel, StructuredLogger } from './lib/system_logger.js'

src/lib/system_logger.ts

@@ -1,5 +1,3 @@
-import { env } from 'process'
-
 const systemLogTag = '__nfSystemLog'
 
 const serializeError = (error: Error): Record<string, unknown> => {
@@ -18,61 +16,61 @@ export enum LogLevel {
   Debug = 1,
   Log,
   Error,
+  Silent = Number.POSITIVE_INFINITY,
 }
 
-class SystemLogger {
+type RawLogger = (...data: unknown[]) => void
+
+export class StructuredLogger {
   private readonly fields: Record<string, unknown>
   private readonly logLevel: LogLevel
+  private readonly rawLogger?: RawLogger
 
-  constructor(fields: Record<string, unknown> = {}, logLevel = LogLevel.Log) {
+  constructor(logLevel: LogLevel, rawLogger?: RawLogger, fields: Record<string, unknown> = {}) {
     this.fields = fields
     this.logLevel = logLevel
+    this.rawLogger = rawLogger
   }
 
-  private doLog(logger: typeof console.log, message: string) {
-    if (env.NETLIFY_DEV && !env.NETLIFY_ENABLE_SYSTEM_LOGGING) {
-      return
-    }
+  private doLog(message: string, level: string, defaultLogger: RawLogger) {
+    const logger = this.rawLogger ?? defaultLogger
 
-    logger(systemLogTag, JSON.stringify({ msg: message, fields: this.fields }))
+    logger(systemLogTag, JSON.stringify({ msg: message, fields: this.fields, level }))
   }
 
   log(message: string) {
     if (this.logLevel > LogLevel.Log) {
       return
     }
 
-    this.doLog(console.log, message)
+    this.doLog(message, 'log', console.log)
   }
 
   debug(message: string) {
     if (this.logLevel > LogLevel.Debug) {
       return
     }
 
-    this.doLog(console.debug, message)
+    this.doLog(message, 'debug', console.debug)
   }
 
   error(message: string) {
     if (this.logLevel > LogLevel.Error) {
       return
     }
 
-    this.doLog(console.error, message)
+    this.doLog(message, 'error', console.error)
   }
 
   withLogLevel(level: LogLevel) {
-    return new SystemLogger(this.fields, level)
+    return new StructuredLogger(level, this.rawLogger, this.fields)
   }
 
   withFields(fields: Record<string, unknown>) {
-    return new SystemLogger(
-      {
-        ...this.fields,
-        ...fields,
-      },
-      this.logLevel,
-    )
+    return new StructuredLogger(this.logLevel, this.rawLogger, {
+      ...this.fields,
+      ...fields,
+    })
   }
 
   withError(error: unknown) {
@@ -82,4 +80,4 @@ class SystemLogger {
   }
 }
 
-export const systemLogger = new SystemLogger()
+export const systemLogger = new StructuredLogger(LogLevel.Log)

test/unit/system_logger.js

@@ -1,29 +1,44 @@
-const process = require("process")
-
 const test = require('ava')
 
-const { systemLogger, LogLevel } = require('../../dist/internal')
+const { systemLogger, LogLevel, StructuredLogger } = require('../../dist/internal')
+
+const consoleDebug = console.debug
+const consoleError = console.error
+const consoleLog = console.log
+
+test.afterEach(() => {
+  console.debug = consoleDebug
+  console.error = consoleError
+  console.log = consoleLog
+})
 
-test('Log Level', (t) => {
-  const originalDebug = console.debug
+test('Log levels', (t) => {
+  const logs = {
+    debug: [],
+    error: [],
+    log: [],
+  }
+  console.debug = (...message) => logs.debug.push(message)
+  console.error = (...message) => logs.error.push(message)
+  console.log = (...message) => logs.log.push(message)
 
-  const debugLogs = []
-  console.debug = (...message) => debugLogs.push(message)
+  systemLogger.debug('debug 1')
+  t.is(logs.debug.length, 0)
 
-  systemLogger.debug('hello!')
-  t.is(debugLogs.length, 0)
+  systemLogger.log('log 1')
+  t.is(logs.log.length, 1)
 
-  systemLogger.withLogLevel(LogLevel.Debug).debug('hello!')
-  t.is(debugLogs.length, 1)
+  systemLogger.withLogLevel(LogLevel.Debug).debug('debug 2')
+  t.is(logs.debug.length, 1)
 
-  systemLogger.withLogLevel(LogLevel.Log).debug('hello!')
-  t.is(debugLogs.length, 1)
+  systemLogger.withLogLevel(LogLevel.Debug).error('error 1')
+  t.is(logs.error.length, 1)
 
-  console.debug = originalDebug
+  systemLogger.withLogLevel(LogLevel.Silent).error('error 2')
+  t.is(logs.error.length, 1)
 })
 
 test('Fields', (t) => {
-  const originalLog = console.log
   const logs = []
   console.log = (...message) => logs.push(message)
   systemLogger.withError(new Error('boom')).withFields({ foo: 'bar' }).log('hello!')
@@ -34,26 +49,49 @@ test('Fields', (t) => {
   t.is(log.fields.foo, 'bar')
   t.is(log.fields.error, 'boom')
   t.is(log.fields.error_stack.split('\n').length > 2, true)
-
-  console.log = originalLog
+  t.is(log.level, 'log')
 })
 
-test('Local Dev', (t) => {
-  const originalLog = console.log
-  const logs = []
-  console.log = (...message) => logs.push(message)
-  systemLogger.log('hello!')
-  t.is(logs.length, 1)
+test('Accepts a custom raw logger', (t) => {
+  const logs = {
+    debug: [],
+    error: [],
+    log: [],
+  }
+  console.debug = () => {
+    throw new Error('Unexpected `console.debug` call')
+  }
+  console.error = () => {
+    throw new Error('Unexpected `console.error` call')
+  }
+  console.log = () => {
+    throw new Error('Unexpected `console.log` call')
+  }
+  const rawLogger = (tag, payload) => {
+    t.is(tag, '__nfSystemLog')
 
-  process.env.NETLIFY_DEV= "true"
-  systemLogger.log('hello!')
-  t.is(logs.length, 1)
+    const { msg, fields, level } = JSON.parse(payload)
+    const bucket = logs[level]
+
+    t.truthy(bucket)
+
+    bucket.push({ fields, msg })
+  }
+
+  const logger = new StructuredLogger(LogLevel.Log, rawLogger, {})
+
+  logger.debug('debug 1')
+  t.is(logs.debug.length, 0)
+
+  logger.log('log 1')
+  t.is(logs.log.length, 1)
+
+  logger.withLogLevel(LogLevel.Debug).debug('debug 2')
+  t.is(logs.debug.length, 1)
 
-  process.env.NETLIFY_ENABLE_SYSTEM_LOGGING= "true"
-  systemLogger.log('hello!')
-  t.is(logs.length, 2)
+  logger.withLogLevel(LogLevel.Debug).error('error 1')
+  t.is(logs.error.length, 1)
 
-  delete process.env.NETLIFY_DEV
-  delete process.env.NETLIFY_ENABLE_SYSTEM_LOGGING
-  console.log = originalLog
+  logger.withLogLevel(LogLevel.Silent).error('error 2')
+  t.is(logs.error.length, 1)
 })