Rails - creating "huge" XML file on Heroku - ruby-on-rails

Once a month I need to create almost 40MB XML file in my Rails app and save this file. As a storage I use Amazon S3 platform. When I do this task on my localhost (Webrick server), this task takes like 5 minutes => the file is saved in the Amazon's bucket. All are happy.
But when I run this task on Heroku, the app is not responding like 45 minutes and the file is not saved in Amazon.
I know heroku allows to run a task for just 30 seconds, but after this time is displayed an error message and the task is running in the background. While this operation is the app "idle".
But, how is possible that the file is not created and saved? Is there any limitation on Heroku for file transfer or something like that?
I spent whole afternoon with searching the problem, but until now without success.
Thanks in advance

I'm pretty sure the process is killed after 30 seconds, not running in the background as you suggest. Use delayed_job to get backgrounding as detailed here: https://devcenter.heroku.com/articles/delayed-job. If you have a single method that creates and transfers your file you can just use delayed_job's delay method on that. Note that a delayed_job spins up its own little environment. So in my case, I write the file to tmp and then transfer that to S3 and note that all has to be done in the same job because when the first job is done that tmp directory evaporates.

Related

Heroku active storage S3 Seahorse::Client::NetworkingError (Net::OpenTimeout)

I am having a really weird issue. We are using the following combination
Rails 7.0.0 master branch
Heroku
Active Storage
Bucketeer addon
Staging app
Production app
I have two environments staging and production. On staging everything works fine, on production I keep running into: Seahorse::Client::NetworkingError (Net::OpenTimeout). The heroku support was, unfortunately, less than helpful (was worth a shot) so I am asking here.
If I use s3 directly, from a rails console, everything works fine. I can upload and download objects from my bucket so I know for a fact that the environment variables are valid.
If I on the other hand, try to upload a user avatar using active storage I get this error message: Seahorse::Client::NetworkingError (Net::OpenTimeout), which, to me, indicates a complete failure to connect to S3.
I have experimented with different timeouts both for active storage's storage.yml and for the global amazon configuration with no differing result. The error seems to be returned faster than the timeout (open timeout of 15 seconds should wait 15 seconds but it does not).
Any pointers in the right direction greatly appreciated.
After deleting config/credentials/production.yml everything is well.

Using delayed_paperclip in Sidekiq in Heroku

I have an issue which is strangely not addressed anywhere.
I am using paperclip to upload attachments to S3 in a Heroku app. But since the upload takes time i started using delayed_paperclip. But the issue is the Sidekiq worker fails with a error message that 'unable to open the file or file not found'. This makes perfect sense as the heroku worker and web are running on different dynos.
Is there any solution to it? except that the web has to upload it to S3, which defeats the whole purpose.
The bottom line problem for me is I am unable to share files in tmp folder between the web and the worker
The upload process is not related to your Rails App at all, you are going to have improvements if processing the file is taking too much time, but in your case, the problem sounds like it's related to a big file and slow network

Are files uploaded to heroku immediately deleted?

I see everywhere that heroku deletes changes you made to the filesystem once you deploy or scale your application but in my case it seems files disappear immediately.
My rails application uploads files to public/uploads and then a delayed job tries to read those files, when it tries to read them they are not found.
If I do everything in the same thread it works, but when I try to use the delayed job or check the filesystem using heroku run bash the files are gone.
Why this happens?
heroku is a read only file system. so actually you don't even write the files but just keep them in memory while in one thread.
if you want to use some free storage system i recommend google drive. you'll need to do some searching of how to use that since not too long ago they changed they're login policy only with Oauth, no more password/username login

How to deploy to Heroku without losing tmp files?

I have a scheduled job running every 12 hrs that unzips image files from an FTP server into my tmp folder. The problem is that due to Heroku's ephemeral filesystem, whenever I deploy new code, the tmp folder is cleared when the dyno's restart and the files are no longer there. I'd like to be able to deploy code at will, without this concern.
I have thought of creating a second app that runs this task and connects to the same database. As per this SO answer. This way I can deploy code updates unrelated to this task to my production server, and can chose more selectively when to deploy to the second server.
Does anyone have any experience with having two apps running on the same database? Or is there a better way to solve my issue? I've read that Heroku may change database URL's at any time, so the second app may lose its connection. How common is this? Thanks!
I would create a folder under public e.g. public/storage and save unzipped files here.
I believe that it is possible using an app on Heroku.
Check this out: https://devcenter.heroku.com/articles/s3

Saving editable data in Rails 3 on Heroku

My rails app allows users to edit a certain json file through the browser. This data file is saved in app/assets/data/thefile.json (the site is only used internally)
I tested the front-end locally and it worked fine, the data gets updated and saved. Then I pushed the code to Heroku and tested it there as well. It worked. However after about 1 day when I go back to the site, I realized that the data has reverted to its original state before it was edited.
This happened numerous times and I'm not so sure why it happened. Maybe because Heroku does not allow files in the app folder to be edited?
Any advice would be greatly appreciated!
Probably has something to do with the fact that Heroku has a read only file system.
There's also a note here on the ephemeral file system
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.

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