[App Server] Image (png) from server to client

Anvil Q&A
1

Hi
I have an Anvil app which I have moved locally, I managed to get it work on an Ubuntu 18.04 Testserver. Now I am forced to move the app onto a productive Ubuntu 20.04 system and run the app as a service.

I have have set up the Anvil app in /opt/company/AnvilApp where the service user is the owner of the AnvilApp folder and all its content.

The Anvil App runs on port 443 (using SSL), 443 is the only open port.
On Ubuntu 18.04, where everything works, I am using Anvil-App-Server 1.2
On Ubung 20.04, where I have the trouble, I am using a more recent version, namely 1.6.2

I managed to get the app running. However, during use of the app the app creates png images which are temporarily stored in /var/tmp/AnvilApp/ (every user has the right to read the folder content).

Following the creation of the png file, I am trying to load the image file again and send it to the client:

Server code:

@anvil.server.callable
def get_image:
  image = anvil.media.from_file("/var/tmp/patmap/GK_"+anvil.users.get_user()['email'][:5]+".png", "image/png")
  print(type(image))   #gives: [DEBUG anvil.app-server.run] [SERVER] <class 'anvil.BlobMedia'>
  return image

Client Code (fraction):

self.image_1.source = anvil.server.call ("get_image")

Instead of a nice rendering in the browser I get the following message on the server:

EOFError while reading worker stdout. This should not have happened.
Server code exited unexpectedly: 4385752d12 (IDs server-PNmhfdzwfUN2Zw==)
Worker terminated for IDs {‘server-PNmhfdzwfUN2Zw==’} (return code None)

Unfortunately I have no clue what this cryptic message wants to tell me :cry:.

Has anybody out there an idea what I’m doing wrong? Please!

Regards,

Vinz