Hi,
I’m looking into a possibility to detect if GWC created all requested tiles when seeding.
At the moment I see two possibilities to achieve this:
- Look into GeoServer’s logfile, but this would be hard to interpret.
- Count the files on disk, unfortunately this is unreliable.
So, is there a better way to tell if seeding was successful and if not, how many tiles are missing?
A bit of background:
As part of a bigger workflow I’m seeding tiles (via REST calls), that I then further process and deploy to different servers. As seeding doesn’t always produce the desired result (f.e. due to an unstable source WMS service), I’m looking for a possibility to determine if all tiles have been created. At the moment I’m counting the resulting files on disk and comparing it to the total number of tiles to process returned from the layer’s status REST endpoint. Sometimes the figures match, but sometimes GWC creates less tiles than expected although no errors had been written to the GeoServer logfile. So it’s hard to say if there were errors or if GeoWebCache
just decided to omit some tile rows or columns at the border region of the BBOX.
So I tried to predict the minimum and maximum tile numbers in x and y direction, that should be created for a given BBOX. As the calculated numbers initially didn’t match the total number of tiles to process, I assumed that the BBOX will be enlarged by GWC to match an imagined grid that is defined by the metatile size. Now my total number of tiles matches the number estimated by GWC and I can see the difference in rows and columns between my calculation and the output of GWC, f.e.:
Calculated: left=35130, bottom=42687, right=35159, top=42716
Created: left=35130, bottom=42687, right=35157, top=42716
So it would be interesting to know how GWC decides, which tiles to create.
Regards
Daniel