Heroku things

Logs on prod to debug with specific messages

List all environment variables on herolu to local terminal

Problem only on production when you use multiple dynos

The big different between dev and prod may come from the settings of using 1 or many dynos (sub processes). Your app may use something like node-cache to store in a short term something and then want to get back later. However, in the prod mode, between 2 different requests, they may use 2 different dynos for the task. That’s why the things you stored in cache from 1 dyno cannot be found in another dyno. This problem doesn’t happen in the dev mode because we usually use only 1 dyno.

You can check in the logs, there will be something like app[web.1] or app[web.2] at the beginning of each log message. They indicate the corresponding dyno they are using.

One solution for you is using a “global cache” addons. There are heroku-redis (limit connections even with paid), MemCachier (no limit connections with paid).

Logs on prod to debug with specific messages

1heroku logs --source app --tail --app app-name-prod | grep "DINHANHTHI"

1// On backend
2Logger.debug('DINHANHTHI something else...')

List all environment variables on herolu to local terminal

Official doc.

1heroku config --app app-name

Problem only on production when you use multiple dynos

You can check in the logs, there will be something like app[web.1] or app[web.2] at the beginning of each log message. They indicate the corresponding dyno they are using.

One solution for you is using a “global cache” addons. There are heroku-redis (limit connections even with paid), MemCachier (no limit connections with paid).