feat: flush & flushSync

lib/proto.js

@@ -38,7 +38,6 @@ const constructor = class Pino {}
 const prototype = {
   constructor,
   child,
-  flush,
   isLevelEnabled,
   version,
   get level () { return this[getLevelSym]() },
@@ -97,8 +96,3 @@ function write (obj, msg, num) {
   if (stream instanceof SonicBoom) stream.write(s)
   else stream.write(flatstr(s))
 }
-
-function flush () {
-  const stream = this[streamSym]
-  if ('flushSync' in stream) stream.flushSync()
-}

lib/tools.js

@@ -11,6 +11,7 @@ const {
   messageKeyStringSym,
   serializersSym,
   formatOptsSym,
+  streamSym,
   endSym,
   stringifiersSym,
   stringifySym,
@@ -197,11 +198,21 @@ function createArgsNormalizer (defaultOptions) {
   }
 }
 
+function flush () {
+  this[streamSym].flush()
+}
+
+function flushSync () {
+  this[streamSym].flushSync()
+}
+
 module.exports = {
   noop,
   getPrettyStream,
   asChindings,
   asJson,
   genLog,
-  createArgsNormalizer
+  createArgsNormalizer,
+  flush,
+  flushSync
 }

pino.js

@@ -9,7 +9,7 @@ const time = require('./lib/time')
 const proto = require('./lib/proto')
 const symbols = require('./lib/symbols')
 const { mappings, genLsCache, assertNoLevelCollisions } = require('./lib/levels')
-const { createArgsNormalizer, asChindings } = require('./lib/tools')
+const { createArgsNormalizer, asChindings, flush, flushSync, noop } = require('./lib/tools')
 const { version, LOG_VERSION } = require('./lib/meta')
 const {
   chindingsSym,
@@ -82,10 +82,13 @@ function pino (...args) {
   const time = (timestamp instanceof Function)
     ? timestamp : (timestamp ? epochTime : nullTime)
 
+  const extreme = stream.minLength === 4096
   const levels = mappings(customLevels)
 
   const instance = {
     levels,
+    flush: extreme ? flush : noop,
+    flushSync: extreme ? flushSync : noop,
     [streamSym]: stream,
     [timeSym]: time,
     [stringifySym]: stringify,
@@ -98,7 +101,6 @@ function pino (...args) {
     [chindingsSym]: chindings
   }
   Object.setPrototypeOf(instance, proto)
-
   if (customLevels) genLsCache(instance)
 
   events(instance)

test/extreme.test.js

@@ -7,6 +7,7 @@ const { test } = require('tap')
 const { fork } = require('child_process')
 const writer = require('flush-write-stream')
 const { once } = require('./helper')
+const pino = require('..')
 
 test('extreme mode', async ({is, teardown}) => {
   const now = Date.now
@@ -119,7 +120,40 @@ test('throw an error if extreme is passed', async ({throws}) => {
   })
 })
 
-test('flush does nothing without extreme mode', async () => {
-  var instance = require('..')()
+test('flush is a no-op with non-extreme destinations', async ({is}) => {
+  const instance = require('..')()
+  is(instance.flush.toString(), 'function noop () {}')
+})
+
+test('logger.flush calls dest.flush on extreme destinations', async ({pass, fail}) => {
+  const dest = pino.extreme()
+  var passed = false
+  setTimeout(() => { if (passed === false) fail() })
+  const flush = dest.flush
+  dest.flush = () => {
+    passed = true
+    dest.flush = flush
+    pass('synchronously flushed')
+  }
+  const instance = require('..')(dest)
   instance.flush()
 })
+
+test('flushSync is a no-op with non-extreme destinations', async ({is}) => {
+  const instance = require('..')()
+  is(instance.flushSync.toString(), 'function noop () {}')
+})
+
+test('logger.flushSync calls dest.flushSync on extreme destinations', async ({pass, fail}) => {
+  const dest = pino.extreme()
+  var passed = false
+  setTimeout(() => { if (passed === false) fail() })
+  const flushSync = dest.flushSync
+  dest.flushSync = () => {
+    passed = true
+    dest.flushSync = flushSync
+    pass('synchronously flushed')
+  }
+  const instance = require('..')(dest)
+  instance.flushSync()
+})