[mapserver-dev] Projections and CONFIG file in MapServer 8.0

[Jeff McKenna]

I can dream of a 'PROJ_LIB_LOCATION_PRIORITY' setting in the MapServer 
.conf file:

   1 : use .conf setting
   2 : use setting inside your .mapfile or .include
   3 : use setting from Web Server (Apache conf, etc.)
   4 : use setting at the System environment level [warning to Windows 
Server admins, this is problematic on some systems in several ways: 
often not found, or conflicts with other FOSS4G software settings for PROJ]


Or, the old rule applies here: 'never send an important email after 6pm' ha!

Thanks for listening,

-jeff






On 2022-07-06 8:12 p.m., Jeff McKenna wrote:
> Ok thanks Steve, but can you be more specific regarding 'local setting'? 
>   On Windows each FOSS4G software has its own PROJ instance/version and 
> its own PROJ_LIB variable (yes it's complete disaster, waiting to 
> happen).  So where does the mapfile's PROJ_LIB setting, and then the 
> System environment variable fit into your 3 ?
> 
> Thanks,
> 
> -jeff
> 
> 
> 
> On 2022-07-06 6:44 p.m., Steve Lime wrote:
>> I understand your logic and would agree for most things. However, one 
>> benefit of the config file is to allow admins to lock things down - 
>> especially items like environment variable settings that tell 
>> MapServer to load code. Hence my original response, so 1) config file, 
>> 2) web server environment, 3) local setting.
>>
>> --Steve
>>
>> On Wed, Jul 6, 2022 at 4:05 PM Jeff McKenna 
>> <jmckenna at gatewaygeomatics.com <mailto:jmckenna at gatewaygeomatics.com>> 
>> wrote:
>>
>>     Oh don't forget PostGIS' use of that same variable (that's where I 
>> hit
>>     this on servers constantly).
>>
>>     So, my point is, that the only way we can avoid all this 
>> "environment"
>>     variable chaos is first always use the local mapfile setting, then 
>> look
>>     for .conf, and if neither has this, check the other sources.
>>
>>     -jeff
>>
>>
>>
>>     On 2022-07-06 6:01 p.m., Jeff McKenna wrote:
>>      > I think we have several possibilities: environment var (system
>>      > variable), web server environment variable (Apache config),
>>     MapServer
>>      > .conf, and local mapfile setting.
>>      >
>>      > I would say that the local mapfile should always be used first by
>>      > MapServer, in this order:
>>      >
>>      > - check mapfile setting,
>>      > - if not found, check for MapServer .conf setting,
>>      > - if not found, check for web server setting
>>      > - if not found, check for system environment variable
>>      > - ...else, battle for superiority with the other PROJ_LIB
>>     settings by
>>      > the other FOSS4G software on that container
>>      >
>>      > Notes:
>>      >
>>      > - this shared PROJ_LIB issue is not just for MapServer, but is
>>     faced by
>>      > all FOSS4G projects that share this variable.  On Windows servers
>>     now it
>>      > is common for me to have several PROJ_LIB settings, one for each
>>     FOSS4G
>>      > software that depends on (depends on that PROJ version for that
>>      > software), such as QGIS, GDAL, MapServer, etc. etc.  Meaning: f
>>     you need
>>      > a job run for one software, enable that specific PROJ_LIB.
>>      >
>>      > It's fun :)
>>      >
>>      > -jeff
>>      >
>>      >
>>      >
>>      >
>>      >
>>      > On 2022-07-06 5:49 p.m., Steve Lime wrote:
>>      >> This could/would have been the case in past versions as well,
>>     right?
>>      >> So I don't think this is a new issue. IMHO I'd think central 
>> config
>>      >> settings should trump local settings for something like this.
>>      >>
>>      >> On Wed, Jul 6, 2022 at 2:40 PM Seth G <sethg at geographika.co.uk
>>     <mailto:sethg at geographika.co.uk>
>>      >> <mailto:sethg at geographika.co.uk
>>     <mailto:sethg at geographika.co.uk>>> wrote:
>>      >>
>>      >>     Hi all,
>>      >>
>>      >>     Using MapServer 8.0 beta and FastCGI (on Windows) I'm
>>     running into
>>      >>     an issue where the PROJ_LIB setting is sometimes set by the
>>     value in
>>      >>     the CONFIG file and sometimes by the setting in the Mapfile:
>>      >>
>>      >>     CONFIG
>>      >>        ENV
>>      >>          MS_MAP_PATTERN "."
>>      >>          PROJ_LIB "C:/MapServer/bin/proj7/share" #proj7
>>      >>        END
>>      >>     END
>>      >>
>>      >>     Then in a Mapfile:
>>      >>
>>      >>     CONFIG "PROJ_LIB" "C:/MapServer/bin/proj/SHARE" # uses proj6
>>      >>
>>      >>     Requests will use one PROJ setting then switch to another
>>     seemingly
>>      >>     at random.
>>      >>     Should one always take precedence over the other?
>>      >>
>>      >>     Seth
>>      >>
>>      >>     --
>>      >>     web:https://geographika.net <https://geographika.net>
>>     <https://geographika.net <https://geographika.net>>
>>      >>     twitter: @geographika
>>      >
>>
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-- 
Jeff McKenna
GatewayGeo: Developers of MS4W, MapServer Consulting and Training
co-founder of FOSS4G
http://gatewaygeo.com/