lib: added logger api in node core by mertcanaltin · Pull Request #60468 · nodejs/node

mertcanaltin · 2025-10-28T19:09:56Z

for: #49296 (comment)

I try a draft development for new logger api, and i try create some benchmark for pino and node:logger package

nodejs-github-bot · 2025-10-28T19:10:01Z

Review requested:

@nodejs/performance

lib/logger.js

mertcanaltin · 2025-10-29T19:25:12Z

thats my first performance results:

I think need improvement for child logger area, but ı'm so happy because other results it looks nice.
cc @mcollina @Qard @trentm @jsumners

node:logger vs pino

➜ node git:(mert/create-logger-api/node-core) ✗ ./node benchmark/logger/vs-pino.js n=100000
logger/vs-pino.js scenario="simple" logger="node-logger" n=100000: 5,240,540.823813018
logger/vs-pino.js scenario="child" logger="node-logger" n=100000: 2,635,847.7027229806
logger/vs-pino.js scenario="disabled" logger="node-logger" n=100000: 159,436,487.67795104
logger/vs-pino.js scenario="fields" logger="node-logger" n=100000: 3,619,336.304205216
logger/vs-pino.js scenario="simple" logger="pino" n=100000: 3,398,489.9761368227
logger/vs-pino.js scenario="child" logger="pino" n=100000: 4,489,799.803418606
logger/vs-pino.js scenario="disabled" logger="pino" n=100000: 119,772,384.56038144
logger/vs-pino.js scenario="fields" logger="pino" n=100000: 1,257,930.8609750536

lib/logger.js

benchmark/logger/basic-json.js

benchmark/logger/vs-pino.js

lib/logger.js

mertcanaltin · 2025-10-29T22:14:10Z

I now learn this feat in Pino

pinojs/pino#2281

I will try add in node:logger

lib/logger.js

mcollina · 2025-10-30T08:49:22Z

This will require support for serializers

mertcanaltin · 2025-10-30T10:58:34Z

This will require support for serializers

I wonder, should we name them like Pino does (built-in serializers), or go with something like standardSerializers ?

test/parallel/test-log-basic.js

lib/logger.js

mcollina · 2025-11-08T10:30:09Z

This will require support for serializers

I wonder, should we name them like Pino does (built-in serializers), or go with something like standardSerializers ?

Follow pino and we’ll change it

mertcanaltin · 2025-11-10T13:29:32Z

This will require support for serializers

I wonder, should we name them like Pino does (built-in serializers), or go with something like standardSerializers ?

Follow pino and we’ll change it

I tryed serializer implement for logger, and some bench result repaired

and fields and simple are experiencing a decline; I will try to resolve these

fields: 3.62M → 2.16M (-40%)
simple: 5.24M → 4.87M (-7%)

previously, the results for the child logger were quite slow at around 70%, but the new results have dropped to 18% and have actually improved significantly.

I continue to try new methods.

➜  node git:(mert/create-logger-api/node-core) ✗ ./node benchmark/logger/vs-pino.js n=100000
logger/vs-pino.js scenario="simple" logger="node-logger" n=100000: 4,868,164.032787085
logger/vs-pino.js scenario="child" logger="node-logger" n=100000: 3,894,327.425314102
logger/vs-pino.js scenario="disabled" logger="node-logger" n=100000: 160,503,080.85663706
logger/vs-pino.js scenario="fields" logger="node-logger" n=100000: 2,157,462.3927336666
logger/vs-pino.js scenario="simple" logger="pino" n=100000: 3,424,706.4418693925
logger/vs-pino.js scenario="child" logger="pino" n=100000: 4,753,595.477010947
logger/vs-pino.js scenario="disabled" logger="pino" n=100000: 122,100,122.10012211
logger/vs-pino.js scenario="fields" logger="pino" n=100000: 1,411,215.99189962
➜  node git:(mert/create-logger-api/node-core) ✗

mertcanaltin · 2025-11-10T14:12:02Z

This will require support for serializers

I wonder, should we name them like Pino does (built-in serializers), or go with something like standardSerializers ?

Follow pino and we’ll change it

I tryed serializer implement for logger, and some bench result repaired

and fields and simple are experiencing a decline; I will try to resolve these

fields: 3.62M → 2.16M (-40%) simple: 5.24M → 4.87M (-7%)

previously, the results for the child logger were quite slow at around 70%, but the new results have dropped to 18% and have actually improved significantly.

I continue to try new methods.
➜  node git:(mert/create-logger-api/node-core) ✗ ./node benchmark/logger/vs-pino.js n=100000
logger/vs-pino.js scenario="simple" logger="node-logger" n=100000: 4,868,164.032787085
logger/vs-pino.js scenario="child" logger="node-logger" n=100000: 3,894,327.425314102
logger/vs-pino.js scenario="disabled" logger="node-logger" n=100000: 160,503,080.85663706
logger/vs-pino.js scenario="fields" logger="node-logger" n=100000: 2,157,462.3927336666
logger/vs-pino.js scenario="simple" logger="pino" n=100000: 3,424,706.4418693925
logger/vs-pino.js scenario="child" logger="pino" n=100000: 4,753,595.477010947
logger/vs-pino.js scenario="disabled" logger="pino" n=100000: 122,100,122.10012211
logger/vs-pino.js scenario="fields" logger="pino" n=100000: 1,411,215.99189962
➜  node git:(mert/create-logger-api/node-core) ✗ 

I inspected pino and I learn some patterns, than I applied this commit and new results! 1ededc7

I used this patterns

removed the cost of serializing bindings in each log for the child logger,
skipped unnecessary serializer checks,
used direct string concatenation instead of object merging,
sped up type checking

simple: 6.06M vs 3.48M ops/s (+74% faster)
child: 5.76M vs 4.41M ops/s (+31% faster)
disabled: 174M vs 146M ops/s (+19% faster)
fields: 2.13M vs 1.36M ops/s (+56% faster)

➜  node git:(mert/create-logger-api/node-core) ✗ ./node benchmark/logger/vs-pino.js n=100000
logger/vs-pino.js scenario="simple" logger="node-logger" n=100000: 6,062,182.962986493
logger/vs-pino.js scenario="child" logger="node-logger" n=100000: 5,758,903.394222795
logger/vs-pino.js scenario="disabled" logger="node-logger" n=100000: 174,026,539.04720467
logger/vs-pino.js scenario="fields" logger="node-logger" n=100000: 2,126,059.37552321
logger/vs-pino.js scenario="simple" logger="pino" n=100000: 3,477,918.037575009
logger/vs-pino.js scenario="child" logger="pino" n=100000: 4,407,389.658686015
logger/vs-pino.js scenario="disabled" logger="pino" n=100000: 145,551,509.22359914
logger/vs-pino.js scenario="fields" logger="pino" n=100000: 1,363,125.197883181
➜  node git:(mert/create-logger-api/node-core) ✗

mertcanaltin · 2025-11-20T21:38:11Z

hello @mcollina do you any comments or suggestions for this end commits, I'm curious 🙏 .

codecov · 2025-11-29T16:46:57Z

Codecov Report

❌ Patch coverage is 88.79056% with 76 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.70%. Comparing base (e7d6728) to head (e2b603f).
⚠️ Report is 142 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/logger.js	87.90%	71 Missing ⚠️
lib/internal/logger/serializers.js	93.50%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60468      +/-   ##
==========================================
- Coverage   89.74%   89.70%   -0.04%     
==========================================
  Files         674      678       +4     
  Lines      204395   206665    +2270     
  Branches    39274    39565     +291     
==========================================
+ Hits       183427   185399    +1972     
- Misses      13275    13420     +145     
- Partials     7693     7846     +153

Files with missing lines	Coverage Δ
lib/internal/bootstrap/realm.js	`96.21% <100.00%> (+0.21%)`	⬆️
lib/internal/process/pre_execution.js	`97.34% <100.00%> (+1.37%)`	⬆️
src/node_options.cc	`76.32% <100.00%> (-0.06%)`	⬇️
src/node_options.h	`97.95% <100.00%> (+0.06%)`	⬆️
lib/internal/logger/serializers.js	`93.50% <93.50%> (ø)`
lib/logger.js	`87.90% <87.90%> (ø)`

... and 188 files with indirect coverage changes

🚀 New features to boost your workflow:

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lib/logger.js

lib/internal/logger/serializers.js

…g levels

AugustinMauroy

LGTM !

doc/api/logger.md

test/es-module/test-require-module-transpiled.js

benchmark/logger/vs-pino.js

doc/api/cli.md

test/es-module/test-require-module-transpiled.js

Co-authored-by: Rafael Gonzaga <rafael.nunu@hotmail.com>

mertcanaltin · 2026-02-18T20:04:08Z

@AugustinMauroy @RafaelGSS Thanks for the review, edited your comments

anonrig · 2026-02-25T21:07:20Z

@RafaelGSS please take a look. 7 days passed since your review has been requested.

RafaelGSS

It's missing tests for a significant part of the exposed API. Apart from my comments, why are we copying pino internals instead of vendoring pino (which is more robust and well tested) into core?

I'd love to hear @mcollina and @jsumners thoughts on this PR too.

doc/api/logger.md

RafaelGSS · 2026-02-25T22:29:51Z

doc/api/logger.md

@@ -0,0 +1,819 @@
+# Logger
+
+<!--introduced_in=v26.0.0-->


Unless we flag this as semver-major, this is wrong.

RafaelGSS · 2026-02-25T22:30:45Z

doc/api/logger.md

+
+<!-- source_link=lib/logger.js -->
+
+The `node:logger` module provides high-performance structured logging


We should clarify this is only enabled via --experimental-logger

doc/api/logger.md

RafaelGSS · 2026-02-25T22:33:14Z

doc/api/logger.md

+* `obj` {Object} Object containing `msg` property and additional fields.
+* `error` {Error} Error object to log.
+* `fields` {Object} Additional fields to include in the log record.


It's not clear its impact on the call

RafaelGSS · 2026-02-25T22:33:42Z

doc/api/logger.md

+* `msg` {string} Log message.
+* `obj` {Object} Object containing `msg` property and additional fields.
+* `error` {Error} Error object to log.
+* `fields` {Object} Additional fields to include in the log record.


RafaelGSS · 2026-02-25T22:34:35Z

doc/api/logger.md

+logger.fatal(new Error('Unrecoverable error'));
+```
+
+### `logger.child(bindings[, options])`


Considering child logger instances are a bit complex, I'd also include it as > stability 1.1

RafaelGSS · 2026-02-25T22:38:15Z

lib/internal/logger/serializers.js

+ */
+function serializeErr(error) {
+  if (!isNativeError(error)) {
+    return error;


It's not clear to me why we return if it's not a native error; shouldn't we log/fail instead?

RafaelGSS · 2026-02-25T22:39:15Z

lib/internal/logger/serializers.js

+  // Handle error cause recursively
+  if (error.cause !== undefined) {
+    obj.cause = typeof error.cause === 'object' && error.cause !== null ?
+      serializeErr(error.cause) :


Couldn't it cause a crash if it recurses indefinitely?

RafaelGSS · 2026-02-25T22:40:51Z

lib/logger.js

+// Create channels for each log level
+const channels = {
+  __proto__: null,
+  trace: diagnosticsChannel.channel('log:trace'),


we should document the channel names used somewhere.

RafaelGSS · 2026-02-25T22:46:02Z

@RafaelGSS please take a look. 7 days passed since your review has been requested.

It's a 2.5k lines PR, it's hard to concilate time to review it properly.

Co-authored-by: Rafael Gonzaga <rafael.nunu@hotmail.com>

nodejs-github-bot added the needs-ci PRs that need a full CI run. label Oct 28, 2025

mertcanaltin mentioned this pull request Oct 28, 2025

Structured log package in node core #49296

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mertcanaltin changed the title ~~lib: added logger package in node core~~ lib: added logger api in node core Oct 28, 2025

mertcanaltin changed the title ~~lib: added logger api in node core~~ [WIP] lib: added logger api in node core Oct 28, 2025

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mertcanaltin added 4 commits February 5, 2026 20:23

refactor(logger): update enabled checks to use property access for lo…

87e50d5

…g levels

refactor(logger): remove unused ObjectHasOwn import

d2ab9e1

remove outdated reference to logger level enabled property

c142ab3

remove assertion for logger.enabled function

d01048d

mertcanaltin requested review from AugustinMauroy, Qard, TheOneTheOnlyJJ, avivkeller, marco-ippolito and yvele February 15, 2026 20:04

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Update doc/api/cli.md

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Co-authored-by: Rafael Gonzaga <rafael.nunu@hotmail.com>

benchmark: remove pino comparison benchmark from core

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lib: optimize styleText when validateStream is false #61792

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		<!-- source_link=lib/logger.js -->

		The `node:logger` module provides high-performance structured logging

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