Question

I’m using Python/Django on Heroku (Cedar Stack) and I’ve got a management command that I need to write that will pull a file out of an S3 bucket and process it. I’m not sure I understand how to use the ephemeral filesystem. Are there only certain directories that are writeable? I found an other article that implied that there were only certain folders that were writable (but, it doesn’t seem to apply to the Cedar stack). I found this dev article but it doesn’t go into much detail (note: I do understand that it’s just temporary. I only need to unzip the file and process the file). Can I just create a folder anywhere under the application’s root? And how would I get that? It seems like I could probably just use $HOME. I did a bit of testing by connecting to via

$ heroku run bash

and running:

$ echo #HOME

returns:

/app

and running:

$ mkdir $HOME/tmp

creates a folder in the app’s root and gives with the same user and group as the other files and folders.

So… anything I’m missing here? A better way to do it? Is there an OS environment variable for this? I’ve run “env” and I don’t see a better one.

Answer 1

You can create a file under the ‘/tmp’ directory, and that file will be destroyed after the request is complete. I’m doing this on Cedar, and I haven’t had any problems.