Warn users if the FDB config file was not found/loaded

[kinow]

Is your feature request related to a problem? Please describe.

Hi,

I have an FDB repo deployed on LUMI/CSC, and was trying to access it with a freshly created Singularity container that was tested on MN4/BSC.

It was not working due to a networking folder not being automatically mounted in LUMI, but it took me some minutes to realize what was happening.

It would be useful if FDB logged/warned users that it could not load the configuration file & its schema specified by the user, and instead tried to load the default $FDB_INSTALLATION/etc/fdb/schema.

Describe the solution you'd like

A WARNING maybe in stderr, or stdout alerting the user things might go wrong if they proceed…

Describe alternatives you've considered

It could be logged as debug, and visible only when running something like DEBUG=1 fdb-schema.

Additional context

The error in the singularity container:

bruno@uan01:~> singularity run --env FDB5_CONFIG_FILE=/scratch/folder/fdb-mirror/config.yaml my-container-fdb.sif fdb-schema
Exception: Cannot open /opt/fdb/etc/fdb/schema  (No such file or directory)
** Cannot open /opt/fdb/etc/fdb/schema  (No such file or directory) Caught in  (/usr/src/eckit/src/eckit/runtime/Tool.cc +32 start)
** Exception terminates fdb-schema

Organisation

BSC