Self-host PDF Generation Failed

[jon1]

When an order is submitted a background task is kicked off to generate a PDF export of the order and email it it to relevant parties.

The background task seems to randomly fail with the error, “PDF generation failed: Components did not load within allowed time.”

It works ~98% of the time and failed at a similar pace when using the Anvil hosted platform too. It’s now running on a 4core 8GB or RAM machine that is usually around 10% CPU utilization and 5-6 GB of RAM free. We’re using direct Postgresql DB access running on the same VM and the DB is lightning fast.

We have limited insight into the anvil-runtime under the hood to try to diagnose this issue further. Are there any other logs/details we could try to retrieve? It seems like the anvil-runtime is not taking full advantage of the number of cores and RAM that we have available, is there any way to modify that? Has the anvil-runtime project stagnated, there hasn’t been real updates in 10+ months. Since we were encountering this issue on the hosted version, it seems like our problem may be in the runtime itself.

Thank you

[stefano.menci]

The rendering to pdf happens in a headless chrome, and it very likely use just one core.

There is a 30 second timeout. I haven’t played with the open source server, so I don’t know how to modify that.

This post may help you.

[ianb]

This post was also inspired by the above link and cloning it will give you some hints how to work around the timeout.

Create Any Arbitrarily Large PDF w/ clone link (paid tier features)

Inspired from this FR by @stefano.menci : I created this example app, it takes any list of forms, and if they can be rendered within the individual time limit of one call to anvil.pdf.PDFRenderer, aggregates them all using the new anvil data_files service and then combines them using PyPDF2 which is already available on the paid plan. You would also need the paid plan to use the data_files service. (**see below) It also takes a list of tuples in the format of ('form_name', args, kwargs) so …

[jon1]

This issue was encountered again today. I don’t think the problem is actually with our PDFRenderer code/logic, I think the server/run-time has an internal issue that is causing this. Today’s error, “error_from_server anvil._server.AnvilWrappedError: Exception: ‘PDF generation failed: Could not initialise printing service within allowed time.’”

However, at the same time, the server starts responding to users with this message:

The system has an average load of < 0.2 and usually has 5+ GB of free RAM available. I don’t see any abnormalities when the issue occurs in our netdata dashboard. The webserver still responds successfully (which is a mixed blessing as that prevents my error alert from being generated)…

Any advice from the Anvil Team? I know that this issue was happening when we were using the Anvil Platform and not self-hosting.

Thank you