Cannot read property 'asyncReset' of null

[zkd8907]

• Version: 8.0.0
• Platform: Linux x64

We deployed Node 8.0 on our servers, but found an error when a large number of concurrent requests came.

Stack:

TypeError: Cannot read property 'asyncReset' of null
    at Agent.addRequest (_http_agent.js:170:19)
    at new ClientRequest (_http_client.js:271:16)
    at Object.request (http.js:39:10)

I checked the source file _http_agent.js. Line 170 is socket._handle.asyncReset();. I think it's better to check whehter socket._handle is null before use.

[AndreasMadsen]

You are most likely using a custom agent somewhere in your code. Any change you could check for that? We would always like to understand the cause of the error, rather than just making a blind fix. Preventing asyncReset() from being called by checking socket._handle may cause other issues.

/cc @nodejs/async_hooks

[trevnorris]

@AndreasMadsen Unfortunately I haven't found a better approach than to check if socket._handle exists in the case of passing a custom Agent. We have to do something similar in lib/timers.js because custom timer objects can be passed in (and we do that quite a bit in core)`.

Though we may be able to get around this using a combination of my final proposal at the bottom of #13548 (comment) and what we do in lib/timers.js. Which is we assign a new asyncId to the custom object on async_id_symbol and use that. It may have a strange timing issue about when to run init() but I think that's something we can get around.

[mnutt]

I'm seeing the same error, while using an instantiated agent:

const agent = new http.Agent({
  keepAlive: true,
  maxSockets: 128,
  maxFreeSockets: 64
});

http.request({agent, ....});

Would we see a difference in this approach vs just modifying the limits of the default global agent?

[refack]

I'm seeing the same error, while using an instantiated agent:

@mnutt we've been rolling patches around this area during the last month (#13348, #13092, and soon #14026 and #13839). Are you still seeing this error in node@8.1.3?

[mnutt]

Sorry, I should have mentioned that yes, it was node 8.1.3.

[adiulici]

I'm seeing the same issue on node v8.1.14. Unfortunately it's being thrown inside a dependency (new relic) so I cannot offer much of a detail.

[AndreasMadsen]

@aashil could you try the nightly build, most of the async_hooks fixes are in v8.2.0 which hasn't been released yet (#13744).

[adiulici]

@AndreasMadsen Unfortunately I only see this on my production environment when the number of concurrent users is high, and I can't put a nightly build on it..

[refack]

@adiulici node@8.2.0 was just released some relevant bug fixes are in it. If you are comfortable you could try it.

[rwlaschin]

HI. I'm seeing this issue as well 8.1.4

I'm using a custom agent
const keepAliveAgent = new http.Agent({ keepAlive: true });

I'll try 8.2.0 and see if the issue is resolved.

[rwlaschin]

Unfortunately, no it still happens

2017-07-20T11:31:56-0700 <error> RouteLoader.js:60 () message Cannot read property 'asyncReset' of null error TypeError: Cannot read property 'asyncReset' of null
    at Agent.addRequest (_http_agent.js:171:19)
    at new ClientRequest (_http_client.js:272:16)
    at Object.request (http.js:39:10)
    at Request.send (/Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/server/modules/Bid/Request.js:88:11)
    at /Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/server/modules/Dsp/Manager.js:172:29
    at Utilities.ProcessorRunner.completefn (/Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/server/interfaces/Utilities.js:147:9)
    at /Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/node_modules/async/internal/once.js:12:16
    at iteratorCallback (/Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/node_modules/async/eachOf.js:60:13)
    at /Users/robert/Repositories/ry-openrtb-exchange/rtbexchange/node_modules/async/internal/onlyOnce.js:12:16

It is very frequent.

_{edit trevnorris: place output in code block}