[OSM-dev] Serving multiple maps with one server

[Jon Burgess]

On Wed, 2008-09-24 at 19:54 +0200, Jaume Figueras wrote:
> Hello,
> 
> I'm experimenting with OSM data, Mapnik and mod_tile. I set up a
> server 
> with the planet and works perfectly, but now I would like to serve 
> different maps with different information using the same computer.
> 
> I set up a new database, populate it, and tested it using the
> generate 
> tiles and a new xml file. Perfect.
> 
> So I tried to serve it with mod_tile. Since mod_tile and renderd uses
> a 
> lot of compiled parameters I thought that a solution would be
> compiling 
> another mod_tile as my_mod_tile and loading both in apache. So I
> copied 
> all the mod_tile soft to a new directory, say my_mod_tile, changed
> the 
> parameters (names, directories, etc) in render_config.h, changed the 
> filenames to my_mod_tile, changed the module name inside
> my_mod_tile.c 
> changed the Makefile and modules.mk filenames acordingly, changed the 
> socket in protocol.h, compiled it and correct some
> changed-name-errors 
> and get the my_mod_tile.so installed in apache.

As you point out the mod_tile code does not support multiple layers on
one server. Since you've got as far as you have I suspect the remaining
problem might be the name of the request handlers (r->handler), these
have to be unique to the module . Replace all instances of the following
strings in one of your copies of mod_tile.c:
	"tile_serve"
	"tile_dirty"
	"tile_status"
Perhaps make them "tile2_serve" etc.

The correct longer term answer is to move most of the parameters from
render_config.h into Apache module configuration directives. The
interaction between the mod_tile and renderd would also need some
improvement since the backend render daemon needs to know many of the
paths, name of style file etc.

	Jon