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Boilerplate Heroku Dash App for Long Processes (show and tell)

Hi. We’re working on a generic solution for Dash apps that run relatively long processes (30s to 2 mins) that can be deployed on Heroku without tripping up on server & browser timeouts and still provide a reasonable-ish user experience. To make a new app we just copy-paste the boilerplate, drop in whatever processes and visualizations are needed and deploy.

https://github.com/WileyIntelligentSolutions/wiley-boilerplate-dash-app

Main features:

  • Loading spinner
  • Retrieve css from static files
  • “Please wait” message
  • Frequent refreshing to prevent browser timeout while process is running
  • Long processes are run by a background worker via Redis to prevent server timeout

It pulls in a number of different solutions we found here and elsewhere so perhaps it’s useful to share as an all-in-one for anyone else to adapt and use.

Disclaimer: We’re new to Dash so if anyone spots something to improve on let us know!

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Very nice! There have been several questions on the forum about how to deal with “long running processes”, so this is a really great contribution to the community. Thanks for sharing!

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You’re very welcome! We’ll be refining this over time and pushing updates as we improve :slight_smile:

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Thank you so much for putting this together!

I was a bit in over my head when I was going to deploy my first dash app - and then I start getting timeout errors and find I need to use worker processes! which needless to say I knew nothing about…

Having your code as a template for the worker/request/callback structure was super helpful. Thank you thank you!

For other newbies:
In addition to the Wiley template, I referred to:
https://dash.plot.ly/deployment for deploying to Heroku. (be sure to expose the server variable! wasn’t obvious to me that that was important)
https://conda.io/docs/user-guide/tasks/manage-environments.html for managing environments (I’m on Windows, and using conda instead of pipenv)

-AS

2 Likes

Hi… is this boilerplate code still available? The specified git link doesn’t appear valid any longer.

try this:https://github.com/WileyIntelligentSolutions/wiley-dash-boilerplate2

Thank you very much for sharing. This is really helpful!!!