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View Code? Open in Web Editor NEWDetects node eventloop block and reports where it started
License: MIT License
Detects node eventloop block and reports where it started
License: MIT License
Sorry the error was on my part, feel free to delete this
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Not sure what sort of information you would like, but right after it catches the first block, the application seems to hang
The LICENSE file states MIT, while package.json
declares "ISC". This confuses license-checking tools like license-checker.
Blocked for 2928.1773420104983ms:
at Function.runHooks (~/Projects/staeco/node_modules/sequelize/lib/hooks.js:116:20)
at InstanceValidator._validateAndRunHooks (~/Projects/staeco/node_modules/sequelize/lib/instance-validator.js:108:12)
at InstanceValidator.validate (~/Projects/staeco/node_modules/sequelize/lib/instance-validator.js:93:38)
at model.validate (~/Projects/staeco/node_modules/sequelize/lib/model.js:3733:49)
at Promise.try (~/Projects/staeco/node_modules/sequelize/lib/model.js:3510:21)
at model.save (~/Projects/staeco/node_modules/sequelize/lib/model.js:3507:23)
at model.update (~/Projects/staeco/node_modules/sequelize/lib/model.js:3767:17)
at ~/Projects/staeco/server/endpoints/importer/job/updateById.js:34:14
at Generator.next (<anonymous>)
at step (~/Projects/staeco/server/endpoints/importer/job/updateById.js:16:191)
at ~/Projects/staeco/server/endpoints/importer/job/updateById.js:16:361
at <anonymous>
<--- Last few GCs --->
[729:0x102802200] 2320969 ms: Mark-sweep 1518.7 (2703.1) -> 1518.0 (2703.1) MB, 386.3 / 0.0 ms allocation failure GC in old space requested
[729:0x102802200] 2321334 ms: Mark-sweep 1518.0 (2703.1) -> 1517.9 (2657.1) MB, 364.9 / 0.0 ms last resort
[729:0x102802200] 2321698 ms: Mark-sweep 1517.9 (2657.1) -> 1517.9 (2652.1) MB, 364.2 / 0.0 ms last resort
<--- JS stacktrace --->
==== JS stack trace =========================================
Security context: 0x11b70a71cef1 <JSObject>
0: builtin exit frame: Function(aka Function)(this=0x11b70a702241 <undefined>,0xc57a3ffd2b1 <Very long string[3348]>,0x34426c74e3f1 <String[7]: rowData>,0x2ec7a023ad39 <String[7]: parsers>)
2: addFields [/Users/contra/Projects/staeco/node_modules/pg/lib/result.js:110] [bytecode=0x383cc25ff129 offset=180](this=0x3e19048f5ee1 <Result map = 0x3932693dff81>,fieldDescriptions=0x37c73025c619 ...
FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
1: node::Abort() [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
2: node::FatalException(v8::Isolate*, v8::Local<v8::Value>, v8::Local<v8::Message>) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
3: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
4: v8::internal::Factory::NewFixedArray(int, v8::internal::PretenureFlag) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
5: v8::internal::HashTable<v8::internal::StringTable, v8::internal::StringTableShape, v8::internal::HashTableKey*>::EnsureCapacity(v8::internal::Handle<v8::internal::StringTable>, int, v8::internal::HashTableKey*, v8::internal::PretenureFlag) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
6: v8::internal::StringTable::LookupKey(v8::internal::Isolate*, v8::internal::HashTableKey*) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
7: v8::internal::AstValueFactory::Internalize(v8::internal::Isolate*) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
8: v8::internal::parsing::ParseProgram(v8::internal::ParseInfo*, v8::internal::Isolate*, bool) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
9: v8::internal::(anonymous namespace)::CompileToplevel(v8::internal::CompilationInfo*) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
10: v8::internal::Compiler::GetFunctionFromEval(v8::internal::Handle<v8::internal::String>, v8::internal::Handle<v8::internal::SharedFunctionInfo>, v8::internal::Handle<v8::internal::Context>, v8::internal::LanguageMode, v8::internal::ParseRestriction, int, int, int, int, int, v8::internal::Handle<v8::internal::Object>, v8::ScriptOriginOptions) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
11: v8::internal::Compiler::GetFunctionFromString(v8::internal::Handle<v8::internal::Context>, v8::internal::Handle<v8::internal::String>, v8::internal::ParseRestriction, int) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
12: v8::internal::(anonymous namespace)::CreateDynamicFunction(v8::internal::Isolate*, v8::internal::BuiltinArguments, char const*) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
13: v8::internal::Builtin_FunctionConstructor(int, v8::internal::Object**, v8::internal::Isolate*) [/Users/contra/.nvm/versions/node/v8.4.0/bin/node]
14: 0x14d94aabc8dd
commenting out the code gets rid of the issue, so i'm 100% sure its coming from blocked-at.
code:
import blocked from 'blocked-at'
import cleanStack from 'clean-stack'
import createLogger from 'lib/log'
// debug event loop blocks
const debug = createLogger({ name: 'server:event-loop' })
if (process.env.NODE_ENV === 'development') {
blocked((time, stack) => {
if (time < 500) return
// filter out worthless bluebird stuff
const filtered = stack.filter((msg) => msg.indexOf('node_modules/bluebird') === -1)
if (filtered.length === 0) return
// filter out more worthless crap
const nstack = cleanStack(filtered.join('\n'), { pretty: true })
if (nstack.length === 0) return
const msg = `Blocked for ${time}ms:\n${nstack}`
if (time > 10000) return debug.error(msg)
if (time > 1000) return debug.warn(msg)
debug(msg)
})
}
Whenever I start the process, it triggers hundreds of errors, all nearly identical to the following:
7/12/2020, 12:49:30 AM [WARN] Blocked (51.30170703125ms) [
' at link (internal/modules/esm/module_job.js:42:32)',
' at new ModuleJob (internal/modules/esm/module_job.js:63:19)',
' at Loader.getModuleJob (internal/modules/esm/loader.js:242:11)'
]
let result = [];
blocked((time, stack) => {
result = result.concat(stack);
console.log('engine.js blocked', time, stack);
}, { threshold: 20 });
engine.js blocked 23.87353503417969 [ ' at process.nextTick (internal/process/next_tick.js:270:7)',
' at handleOperationCallback (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:468:24)',
' at /home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:504:9',
' at authenticateStragglers (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:443:16)',
' at Connection.messageHandler (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:477:5)',
' at Socket.<anonymous> (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/connection.js:331:22)',
' at emitOne (events.js:115:13)',
' at Socket.emit (events.js:210:7)',
' at addChunk (_stream_readable.js:266:12)',
' at readableAddChunk (_stream_readable.js:253:11)',
' at Socket.Readable.push (_stream_readable.js:211:10)',
' at TCP.onread (net.js:585:20)' ]
engine.js blocked 24.23693408203125 [ ' at process.nextTick (internal/process/next_tick.js:270:7)',
' at handleOperationCallback (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:468:24)',
' at /home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:504:9',
' at authenticateStragglers (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:443:16)',
' at Connection.messageHandler (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/pool.js:477:5)',
' at Socket.<anonymous> (/home/deploy/apps/syook-tnt-server/node_modules/mongodb-core/lib/connection/connection.js:331:22)',
' at emitOne (events.js:115:13)',
' at Socket.emit (events.js:210:7)',
' at addChunk (_stream_readable.js:266:12)',
' at readableAddChunk (_stream_readable.js:253:11)',
' at Socket.Readable.push (_stream_readable.js:211:10)',
' at TCP.onread (net.js:585:20)' ]
engine.js blocked 24.492054931640624 [ ' at internalConnect (net.js:939:26)',
' at GetAddrInfoReqWrap.emitLookup [as callback] (net.js:1098:7)',
' at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:98:10)' ]
engine.js blocked 24.613239013671876 [ ' at internalConnect (net.js:939:26)',
' at GetAddrInfoReqWrap.emitLookup [as callback] (net.js:1098:7)',
' at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:98:10)' ]
setTCPConnection true
new client connection from ::ffff:43.228.229.58:38268
connection data from ::ffff:43.228.229.58:38268: "|2017-09-23 16:09:40,D4:22:01:00:03:FD,01,001,00,-69,100,|2017-09-23 16:09:40,D4:22:01:00:03:F7,01,003,00,-88,100,|2017-09-23 16:09:40,D4:22:01:00:03:F3,02,001,00,-98,100,003,00,-88,100,|2017-09-23 16:09:40,D4:22:01:00:03:FC,02,001,00,-78,100,003,00,-94,100,|2017-09-23 16:09:40,D4:22:01:00:03:F2,01,003,00,-70,100,|2017-09-23 16:09:40,D4:22:01:00:03:F4,02,001,00,-89,100,003,00,-88,100,|2017-09-23 16:09:40,D4:22:01:00:03:F6,02,001,00,-87,100,003,00,-88,100,|2017-09-23 16:09:40,D4:22:01:00:03:FF,01,001,00,-47,100,|2017-09-23 16:09:40,D4:22:01:00:03:EB,01,001,00,-49,100,|2017-09-23 16:09:40,D4:22:01:00:03:EA,01,001,00,-58,100,|2017-09-23 16:09:40,D4:22:01:00:03:FA,01,001,00,-64,100,|2017-09-23 16:09:40,D4:22:01:00:03:E9,01,001,00,-49,100,|2017-09-23 16:09:40,D4:22:01:00:03:ED,01,001,00,-79,100,|2017-09-23 16:09:40,D4:22:01:00:03:EE,01,001,00,-79,100,|2017-09-23 16:09:40,D4:22:01:00:03:F9,01,001,00,-58,100,|2017-09-23 16:09:40,D4:22:01:00:04:00,01,001,00,-77,100,|2017-09-23 16:09:40,D4:22:01:00:03:F0,01,001,00,-59,100,"
data contains gatewayHandshakeMsg false
mode = IDLE
info: [Stream Log] D4:22:01:00:03:FD reader pings 001 00 -69 100
info: [Stream Log] D4:22:01:00:03:F7 reader pings 003 00 -88 100
info: [Stream Log] D4:22:01:00:03:F3 reader pings 001 00 -98 100
info: [Stream Log] D4:22:01:00:03:F3 reader pings 003 00 -88 100
info: [Stream Log] D4:22:01:00:03:FC reader pings 001 00 -78 100
info: [Stream Log] D4:22:01:00:03:FC reader pings 003 00 -94 100
info: [Stream Log] D4:22:01:00:03:F2 reader pings 003 00 -70 100
info: [Stream Log] D4:22:01:00:03:F4 reader pings 001 00 -89 100
info: [Stream Log] D4:22:01:00:03:F4 reader pings 003 00 -88 100
info: [Stream Log] D4:22:01:00:03:F6 reader pings 001 00 -87 100
info: [Stream Log] D4:22:01:00:03:F6 reader pings 003 00 -88 100
info: [Stream Log] D4:22:01:00:03:FF reader pings 001 00 -47 100
info: [Stream Log] D4:22:01:00:03:EB reader pings 001 00 -49 100
info: [Stream Log] D4:22:01:00:03:EA reader pings 001 00 -58 100
info: [Stream Log] D4:22:01:00:03:FA reader pings 001 00 -64 100
info: [Stream Log] D4:22:01:00:03:E9 reader pings 001 00 -49 100
info: [Stream Log] D4:22:01:00:03:ED reader pings 001 00 -79 100
info: [Stream Log] D4:22:01:00:03:EE reader pings 001 00 -79 100
info: [Stream Log] D4:22:01:00:03:F9 reader pings 001 00 -58 100
info: [Stream Log] D4:22:01:00:04:00 reader pings 001 00 -77 100
info: [Stream Log] D4:22:01:00:03:F0 reader pings 001 00 -59 100
TypeError: Cannot read property 'includes' of undefined
at cleanStack (/home/deploy/apps/syook-tnt-server/node_modules/blocked-at/index.js:9:38)
at AsyncHook.after (/home/deploy/apps/syook-tnt-server/node_modules/blocked-at/index.js:42:28)
at emitAfterNative (async_hooks.js:375:40)
I did some independent testing and confirmed we are having the same performance issues as described in this post. Our CPU utilization spiked to 100% and the node fell over when I tried to use this to find blocking stack traces from a dev envionrment.
https://www.ashbyhq.com/blog/engineering/detecting-event-loop-blockers
I was running node:18.18.1-alpine in k8s with express 4.17.3
npm test fails. Looking a bit closer, .\test\index.js is the failing component (not .\test\runtime.js, which I ran on its own & it passed).
PS C:\Working\blocked-at> node .\test\index.js
slow: 99.777ms
slow: 99.666ms
101.79732501220703 [ ' at new Immediate (timers.js:816:5)',
' at createImmediate (timers.js:858:19)',
' at setImmediate (timers.js:845:10)',
' at Object.<anonymous> (C:\\Working\\blocked-at\\test\\index.js:17:1)',
' at Module._compile (module.js:635:30)',
' at Object.Module._extensions..js (module.js:646:10)',
' at Module.load (module.js:554:32)',
' at tryModuleLoad (module.js:497:12)',
' at Function.Module._load (module.js:489:3)',
' at Function.Module.runMain (module.js:676:10)',
' at startup (bootstrap_node.js:187:16)',
' at bootstrap_node.js:608:3' ]
101.19250700378419 [ ' at Promise.then (<anonymous>)',
' at Immediate.start (C:\\Working\\blocked-at\\test\\cases\\promise.js:9:6)',
' at runCallback (timers.js:789:20)',
' at tryOnImmediate (timers.js:751:5)',
' at processImmediate [as _immediateCallback] (timers.js:722:5)' ]
318.04360400390624 [ ' at Object.lookup (dns.js:182:19)',
' at lookupAndListen (net.js:1496:7)',
' at Server.listen (net.js:1472:7)',
' at Immediate.start (C:\\Working\\blocked-at\\test\\cases\\http.js:11:10)',
' at runCallback (timers.js:789:20)',
' at tryOnImmediate (timers.js:751:5)',
' at processImmediate [as _immediateCallback] (timers.js:722:5)' ]
slow: 99.807ms
100.34066600036621 [ ' at Object.fs.read (fs.js:664:11)',
' at C:\\Working\\blocked-at\\test\\cases\\example.js:20:10',
' at FSReqWrap.oncomplete (fs.js:135:15)' ]
slow: 99.063ms
102.48495599365235 [ ' at Server.connectionListener (_http_server.js:309:10)',
' at emitOne (events.js:116:13)',
' at Server.emit (events.js:211:7)',
' at TCP.onconnection (net.js:1561:8)' ]
slow: 99.716ms
100.05577499389648 [ ' at new Immediate (timers.js:816:5)',
' at createImmediate (timers.js:858:19)',
' at setImmediate (timers.js:845:10)',
' at Immediate.recursive (C:\\Working\\blocked-at\\test\\cases\\recursive.js:6:5)',
' at runCallback (timers.js:791:20)',
' at tryOnImmediate (timers.js:751:5)',
' at processImmediate [as _immediateCallback] (timers.js:722:5)' ]
assert.js:42
throw new errors.AssertionError({
^
AssertionError [ERR_ASSERTION]: Expected test/index.js:17 in stack trace
at Timeout._ [as _onTimeout] (C:\Working\blocked-at\test\index.js:28:3)
at ontimeout (timers.js:475:11)
at tryOnTimeout (timers.js:310:5)
at Timer.listOnTimeout (timers.js:270:5)
PS C:\Working\blocked-at> git rev-parse HEAD
b5751e1fe465de0dfd43de19d42be3c82ed96d8a
PS C:\Working\blocked-at> git describe HEAD
v1.1.2
PS C:\Working\blocked-at> node --version
v8.9.1
PS C:\Working\blocked-at>
I am surprised to see that fs.exists() blocks. Please clarify. Thanks
blocked-at V1.1.2
Node JS V8.9.4
[2018/07/03 11:25:45.933] [INFO] { blockedFor: 1054.224799987793,
stack:
[ ' at Object.fs.exists (fs.js:310:11)',
' at getXYZ (C:\dev\prj1\routes\XYZ.js:122:10)',
' at h.XYZ (C:\dev\prj1\routes\XYZ.js:69:37)',
' at Layer.handle [as handle_request] (C:\dev\prj1\node_modules\express\lib\router\layer.js:95:5)',
' at trim_prefix (C:\dev\prj1\node_modules\express\lib\router\index.js:312:13)',
' at C:\dev\prj1\node_modules\express\lib\router\index.js:280:7',
' at Function.process_params (C:\dev\prj1\node_modules\express\lib\router\index.js:330:12)',
' at next (C:\dev\prj1\node_modules\express\lib\router\index.js:271:10)',
' at SendStream.error (C:\dev\prj1\node_modules\serve-static\index.js:121:7)',
' at emitOne (events.js:116:13)',
' at SendStream.emit (events.js:211:7)',
' at SendStream.error (C:\dev\prj1\node_modules\send\index.js:275:17)',
' at SendStream.onStatError (C:\dev\prj1\node_modules\send\index.js:392:12)',
' at onstat (C:\dev\prj1\node_modules\send\index.js:674:26)',
' at FSReqWrap.oncomplete (fs.js:152:21)' ] }
Hey, I noticed that all my stack traces start with AsyncHook.init so I looked at the source code and the following regex:
const asyncHooksRegEx = /\((internal\/)?async_hooks\.js:/
at index.js:7
doesn't match my stack trace. In my stack traces there is no .js
extension for the async_hooks calls.
Hi there,
first off, thank you for this package, it's come in handy several times and always does a great job.
Documentation, however, could be expanded, and I have a question regarding its use in an ExpressJs middleware.
I would like to use "blocked" to investigate the cause of some timeouts we are experiencing in a controller.
I was wondering if I could do something like:
import { Request, Response, NextFunction } from 'express';
import * as blocked from 'blocked-at';
export default (_req: Request, _res: Response, next: NextFunction): void => {
blocked(
(time: any, stack: any) => {
console.log(`Blocked for ${time}ms, operation started here:`, { stack });
},
{ threshold: 1000 },
);
next();
};
import { Router } from 'express';
import * as RestController from '.';
import ApiKeyAuth from '../../authorization/api-key-auth';
import blocked from '../../middleware/blocked';
router.post('/users', ApiKeyAuth, blocked, RestController.createUser);
I am testing this out with jMeter right now, and I have contrasting feelings on the effectiveness, what are your thoughts on this?
Hi,
I am trying to implement this but getting an error. Not sure why
index.js in the server app
const blocked = require('blocked-at');
let result = [];
const { stop } = blocked((time, stack) => {
result = result.concat(stack)
console.log('blocked', time, stack);
});
getting the following error when i run the server locally
TypeError: Cannot set property 't0' of undefined
at AsyncHook.before (/Users/developer/Syook/syook-tnt-server/node_modules/blocked-at/index.js:30:27)
at emitBeforeNative (async_hooks.js:343:40)
at emitBeforeScript (async_hooks.js:378:5)
at process._tickDomainCallback (internal/process/next_tick.js:209:9)
at Function.Module.runMain (module.js:611:11)
at startup (bootstrap_node.js:158:16)
at bootstrap_node.js:598:3
It seems that blocked-at won't report blocking due to garbage collection. For example, I have the following in my code:
var beg = Date.now();
global.gc();
console.log(Date.now()-beg)
Which in my (crazy) case reports 200ms, but blocked-at seems silent about... Could I be misunderstanding something or is this a real deficiency?
Hi,
If you're using this library, post links to stacktraces here. The more examples we have, the better!
This library is not exactly what async hooks were designed for. While it's working for a few cases I investigated, there might be some edge cases out there. The worst case scenario being a false positive, where it'd report a function that's not blocking the event loop.
This needs some investigation.
If you're using this library, feel free to discuss examples of functions it detected.
Using this method to monitor event loop lag causes additional load to memory and CPU in my case this was about ~15%.
I started with a rather large threshold value five seconds, could that cause just filling the cache map with stack traces and now cleaning up that fast https://github.com/naugtur/blocked-at/blob/master/index.js#L4L4 ?
node 10 will remove it entirely, so this library will cease to work. doubt they will change their mind at this point.
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