proj error on recent master image

[pvgenuchten]

the latest master image gives me problems with projections, something changed in image build (or mapserver)?

    PROJECTION
        "EPSG:4326"
    END

msProcessProjection(): Projection library error. proj error "Invalid PROJ string syntax" for "EPSG:4326"

also tried init=epsg:4326

the master image of last month works fine...

[pvgenuchten]

@geographika indicates it may be related to moving from proj_lib env to proj_data env, based on version of proj

see https://proj.org/en/9.4/usage/environmentvars.html

I added an env param PROJ_DATA, but it has no effect

proj --version
Rel. 9.4.0, March 1st, 2024

[pvgenuchten]

Ok, we found the problem, I'm used to starting my mapfiles with

CONFIG 'PROJ_LIB' '/usr/share/proj/'

With the new version of proj this is problematic, and causes above error.
Because proj resources are on a default location, you can however remove the config line, and all works fine

[geographika]

I can recreate the error by setting the following in a Mapfile in the master Docker image (before any PROJECTION blocks):

CONFIG "PROJ_DATA" "/usr/share/proj/"

I get msProcessProjection(): Projection library error. proj error "Invalid PROJ string syntax" for "init=epsg:4326"

If I set it to the following it runs fine:

CONFIG "PROJ_DATA" "/usr/local/share/proj/"

The base image at https://github.com/OSGeo/gdal/blob/master/docker/ubuntu-small/Dockerfile builds PROJ so I'm not sure why there is a difference. It does download grids from http://download.osgeo.org/proj/proj-datumgrid-latest.zip and puts them in the image - maybe these are incompatible with the PROJ version?

(Probably unrelated) - I don't fully understand the symlink here: https://github.com/camptocamp/docker-mapserver/blob/1445ddc37b439a755bf9ca1515501a8d9921b48d/Dockerfile#L17 - is this tied to a specific PROJ version?

[pvgenuchten]

@sbrunner @geographika I closed as completed, but maybe we should reopen to facilitate more research or documentation

[geographika]

The GDAL base image builds the master version of PROJ from whenever it is tagged (ARG PROJ_VERSION=master). The MapServer Docker image uses ubuntu-small-3.8.5 as gdal as the base image, so the version of PROJ used is whatever is in master at this point in time. The corresponding PROJ DATA files are installed to /usr/local/share/proj/ (ARG PROJ_INSTALL_PREFIX=/usr/local).

I'm not sure, but I'm guessing another version of PROJ is installed onto the image. https://github.com/camptocamp/docker-mapserver/blob/master/ci/dpkg-versions.yaml has ubuntu_22_04/libproj22: 8.2.1-1 listed - maybe this is a dependency of something else? I think this installs to /usr/share/proj/ but doesn't match the PROJ version causing the error.

[sbrunner]

Shouldn't we simply add the environment variable PROJ_DATA in the Dockerfile:

ENV PROJ_DATA=/usr/share/proj/

[pvgenuchten]

I tried a env param proj_data, no effect, either gets overwritten by the config in mapfile or there is a problem with the path; usr/share/proj vs usr/local/share/proj

[sbrunner]

I don't fully understand the symlink here: ...

This is just to make the build work

[geographika]

Shouldn't we simply add the environment variable PROJ_DATA in the Dockerfile:

ENV PROJ_DATA=/usr/share/proj/

Assuming the PROJ install in pkg-versions.yaml is required, then I think updating the sample in mapserver.conf is enough (note the working value is /usr/local/share/proj/). The container is working fine for me without having to set PROJ_DATA (or PROJ_LIB) (I presume it defaults to the correct location?).

@pvgenuchten - a PROJ_DATA setting in a Mapfile will always take precedence over any environment setting or setting in mapserver.conf - I'd suggest removing these and if a custom path is needed setting it in mapserver.conf.

Note, from https://github.com/MapServer/MapServer/pull/6573 on the deprecation plan for PROJ_LIB:

PROJ 9.1 recognizes the PROJ_DATA environment variable, as a replacement for PROJ_LIB (both are still recognized by PROJ >= 9.1. PROJ_LIB will be retired in PROJ 10, whose release is unplanned for now)

[sbrunner]

Assuming the PROJ install in pkg-versions.yaml is required,

No, the version in this file is not required, this file is just used to trigger a rebuild when a package is updated.

[sbrunner]

I just tried to reproduce the issue and I didn't succeed, can you share the files you used to reproduce it?

[geographika]

@sbrunner - the following setup should trigger the error. The data isn't required - just setting the CONFIG "PROJ_DATA" "/usr/share/proj/" in the Mapfile. Not a major issue IMO but not sure what version of PROJ is added to the container in /usr/share/proj/ (and how).

docker pull camptocamp/mapserver:master
docker run --name mapserver_master -d -p 8080:80 -v /exercises/mapfiles:/etc/mapserver/mapfiles camptocamp/mapserver:master
docker exec -it mapserver_master /bin/bash
mapserv -nh "QUERY_STRING=map=/etc/mapserver/mapfiles/countries.map&mode=map"

# msProcessProjection(): Projection library error. proj error "Invalid PROJ string syntax" for "init=epsg:4326"

# docker stop mapserver_master
# docker rm mapserver_master

Mapfile:

MAP
    NAME "mymap"
    SIZE 800 400
    CONFIG "PROJ_DATA" "/usr/share/proj/"
    PROJECTION
        "init=epsg:4326"
    END
    EXTENT -180 -90 180 90
    LAYER
        NAME "countries"
        TYPE POLYGON
        STATUS DEFAULT
        CONNECTIONTYPE FLATGEOBUF
        DATA "data/naturalearth/ne_110m_admin_0_countries.fgb"
        CLASS
            STYLE
                COLOR 60 179 113
                OUTLINECOLOR 255 255 255
                WIDTH 1
            END
        END
    END
END

[yjacolin]

I can reproduced also on my side. The fix looks good (remove CONFIG PROJ_LIB).