[OSM-dev] strange error message from mod_tile

[Stephan Knauss]

Hi,

I've set up a new machine with a mod_tile / Tirex rendering stack.

I see some strange errors in the log file which I don't understand. Any 
help would be appreciated.

I can reproduce it when requesting a tile image considered dirty.
The rendering itself looks fine. For example loading the tile as /dirty 
will trigger a rendering which is visible in tirex-status.

Requesting the image as image will not trigger a rendering. It produces 
strange log lines.

Here are the log lines (shortened for readability):

[tile:debug] ./src/mod_tile.c(1381): tile_translate: op(tile_serve) 
xml(osm) mime(image/png) z(14) x(12612) y(7238)
[tile:info] tile_storage_hook: handler(tile_serve), 
uri(/osm/14/12612/7238.png)
[tile:debug] ./src/mod_tile.c(365): tile_state: determined state of osm 
12612 7238 14 on store 7fbe01e40a60: Tile size: 7124, expired: 1 
created: 1404246259
[tile:debug] ./src/mod_tile.c(166): Connecting to renderd on Unix socket 
/var/lib/tirex/modtile.sock
22:03:21.814464 [tile:info] Requesting style(osm) z(14) x(12612) y(7238) 
from renderer with priority 7
22:03:21.815113 [tile:warn] request_tile: Failed to read response from 
rendering socket No such file or directory

So mod_tile was able to open the socket.
The select() call returned immediately.

But then an error is reported.

Can I trust errno in this situation? I only know that recv() did not 
return the expected number of bytes.


Having tirex-master running in debug mode also gives no clue what's 
happening. I see the request being received.
tirex-master[32229]: Listening for commands on socket 
/var/run/tirex/master.sock
tirex-master[32229]: Listening for mod_tile connections on 
/var/lib/tirex/modtile.sock (UNIX)
tirex-master[32229]: Listening for backend responses
tirex-master[32229]: connection from mod_tile accepted
tirex-master[32229]: read request from mod_tile: ver=2 cmd=7 x=12612 
y=7238 z=14 map=osm

Stephan