Loading sprites is very slow with big SVG

[lxup]

Hello, for several months, I have tried many things to host my own map layers. So, I decided to test Martin. I can now host my mbtiles and also SVGs via Martin using Docker. However, when I use large SVGs (size 500x500 each one for example), accessing the sprite via Maputnik (or maplibre-gl) takes a lot of time (about 20 seconds to load an image of only 1MB). Why? Is this .png image not generated when launching the Docker container? Or is it generated on each call to the sprite URL? I need to have excellent image quality...

[nyurik]

at the moment, every request re-generates the PNG. Caching is at the early stage of development. In the mean time, I highly recommend using nginx or varnish caching in front of Martin for now.

[lxup]

Alright, I understand better now. But why not generate the PNG image when launching the container (I ask as a student, please excuse me if I'm saying something silly haha), since to update the sprites you have to restart the container anyway? And is it possible to specify a size for each SVG (in the config file, for example)?

PS: @nyurik Is it possible to contact you to ask a few questions for a study project (its very hard to find answer for gis stuff)?

[nyurik]

@lxup I agree it should be cached in some way. Options:

• cache on startup, but that won't work well with dynamically combining sprites. Maybe cache just the individual sprites, but generate+cache composite ones on the fly.
• cache on first request - probably better approach, but the first request will always take a bit longer

Regardless, caching implies that any changes to the files will not be picked up. This conflicts with the long standing #288 request - so we would need a way to monitor directory for changes, and update cache when that happens.

Sure, feel free to email me (its on my github main page)