When running the boot process for an app, there's a lag for a significant amount of time (anything over than 1 second) between the time the dyno is started or restarted and the time the process is started.
It's most likely that modifications to the
node binary is causing latency to running the process. In order to see what is happening, we can run Node in debug mode by using
NODE_DEBUG=*, which will output the logs for the steps
node takes to run a process.
This can be executed in a one-off dyno of the app:
heroku run bash -a APP_NAME // one-off dyno booted ~ $ NODE_DEBUG=* node index.js
Or it can be used in the
package.json run script:
"npm start": "NODE_DEBUG=* node index.js"
Or in the
web: NODE_DEBUG=* node index.js
After running this, there will be logs from
Alternatively, Express also has a debug mode that is similar and documented here: https://expressjs.com/en/guide/debugging.html. It can be used the same way by including
DEBUG=express:* in the Node start/web process.