I run a Rails app on Heroku that receives emails via Mailgun. Large attachments trigger timeouts and lead to duplicate uploads. How can I better utilize worker dynos?
# Alternative server configuration
setup_server do |srv|
srv.configure_threads(ENV.fetch('MIN_THREADS_ALT', 1).to_i, ENV.fetch('MAX_THREADS_ALT', 6).to_i)
srv.launch_workers(ENV.fetch('WORKER_COUNT_ALT', 2).to_i) { ActiveRecord::Base.establish_connection(ENV['DATABASE_URL']) }
end
In my experience with similar issues, a clear separation between the web process and background workers is key. I found that quickly acknowledging incoming requests and offloading heavy tasks to a background queue greatly improves reliability. Using something like Sidekiq to process email attachments asynchronously prevented web dynos from experiencing timeouts and negated duplicate processing. It also allowed adjustments in concurrency for worker dynos on Heroku, aligning resources more effectively. Experimenting with job retries and monitoring worker performance helped stabilize the system when dealing with large files.
I have faced similar issues with delayed responses due to heavy email attachments. My solution involved refactoring the email reception flow so that the initial request only queued a background job. This permitted the system to acknowledge the call immediately while the worker dyno handled the extensive post-processing. Additionally, I implemented a check at the worker level to ensure that an attachment wouldn’t be processed more than once, which helped in avoiding duplication. Tuning the worker’s connection pool and testing under load were also essential in stabilizing the performance on Heroku.