How can I get data from Heroku files storage? Where files stored?

Question

I've googled this question a lot, but I haven't found right answer.

I've built an example app on NodeJS without Database connectivity. While developing I stored data in separate dir - "fakeDB", which contains "tests", "questions", "users" dirs and so on. In "tests" there are JSON files represent test data (a set of questions and answers).

When I deployed app on Heroku, tests stored correctly. When new test created, it is saved in "tests" dir and I have an access to it later.

But when I push a new commit to GH repo, tests that were created in Heroku, have been deleted.

How can I get copy of my Heroku repo on local machine?

NOTE: I've run heroku run bash and on ls it printed the list of local files, not from remote. Also, I've run git pull heroku to separate dir, but there were also a set of my previous files without created on Heroku.

Answer 1

Heroku's filesystem is ephemeral:

Each dyno gets its own ephemeral filesystem, with a fresh copy of the most recently deployed code. During the dyno’s lifetime its running processes can use the filesystem as a temporary scratchpad, but no files that are written are visible to processes in any other dyno and any files written will be discarded the moment the dyno is stopped or restarted. For example, this occurs any time a dyno is replaced due to application deployment and approximately once a day as part of normal dyno management.

This means that you can't reliably create files and store them on the local filesystem. They aren't shared across dynos, and they periodically disappear. Furthermore, Heroku doesn't provide a mechanism for easily retrieving generated files.

The official recommendation is to use something like Amazon S3 for storing uploads, generated files, etc. Of course, depending on what's in your files a database might be a better fit.