CODEWITHSUNDEEP
node.jsapiherokutimeouthapi.js
Carlos Mendoza
Carlos Mendoza

Reputation: 81

Heroku H12 Timeout Error with Node.js

Currently, I am working on a REST API using the Node hapijs framework. The API is deployed on Heroku.

There is a GET endpoint in the API that makes a get request to retrieve data from a third party and processes the data before sending a reply. This particular endpoint times out from time to time. When the endpoint times out, Heroku returns an H12 error. Once it has timed out, subsequent requests to that endpoint result in the H12 errors. I have to restart the application on Heroku to get that endpoint working again. No other endpoints in the API are affected in any way by this error and continue to work just fine even after the error has ocurred.

In my debugging process and looking through the logs, it seems that there are times when a response is not returned from the third party API, causing the error.

I've tried the following solutions to try and solve the problem:

  1. I am using the request library to make requests. Hence, I've tried setting a timeout to 5000 ms as part of the options passed in to the request. It has worked at times... the timeout is triggered and the endpoint sends the timeout error associated with request. This is the kind of behavior that I would like, since subsequent requests to the endpoint work. However, there are times when the request timeout is not triggered but Heroku still returns an H12 error (always after 30 seconds, the Heroku default). After that, subsequent requests to that endpoint return the H12 error (also after 30 seconds). It seems that some sort of process gets "stuck" on Heroku and is not terminated until I restart the app.

  2. I've tried adding a timeout to the hapi.js route config object. I get the same results as above.

  3. I've continued doing research and suspect that the issues has to do with the description given here and here. It seems like setting a timeout at the app server level that can send a SIGKILL to the Heroku worker might do the trick. It seems fairly straightforward in Ruby but I cannot find much information on how to do this in Node.

Any insight is greatly appreciated. I am aware that a timeout might occur when making a request to a third party. That is not the issue. The issue is that the endpoint seems to get "stuck" on Heroku after a timeout and it becomes unresponsive.

Thanks for the help!

Upvotes: 2

Views: 3477

Answers (1)

lwdthe1
lwdthe1

Reputation: 1280

I had a similar issue and after giving up for a day, I came back to it and found my error. I wasn't sending a response to the client when an error occurred on the server side. Make sure you are returning a response no matter what the result of your server side algorithm is. If there is an error, return that. If the request was successful, return that response. I hope that helps.

If that doesn't help, check heroku's guides on handling Request Timeouts, especially the Debugging request timeouts section could be of help:

Upvotes: 7

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