Be able to configure Mapnik's logger severity level through options

[dgaubert]

Mapnik uses stdout for logging and we might want to decide what to do with them.

$ node
> const mapnik = require('@carto/mapnik');
undefined
> mapnik.Logger
{ [Function: Logger]
  getSeverity: [Function: getSeverity],
  setSeverity: [Function: setSeverity],
  NONE: 3,
  ERROR: 2,
  DEBUG: 0,
  WARN: 1 }
> mapnik.Logger.getSeverity()
2
> mapnik.Logger.setSeverity(mapnik.Logger.NONE)
undefined
> mapnik.Logger.getSeverity()
3

@Algunenano, do you know what severity level we are setting for the logger while compiling @carto/mapnik?

[dgaubert]

We redirect stdout to a file and it's polluted with messages as follows:

WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
WARNING:  ST_Line_Interpolate_Point signature was deprecated in 2.1.0. Please use ST_LineInterpolatePoint
Mapnik LOG> 2020-05-01 12:20:17: SVG PARSING ERROR:"SVG support error: <font-size> attribute is not supported"
Mapnik LOG> 2020-05-01 12:20:17: SVG PARSING ERROR:"SVG support error: <font-style> attribute is not supported"
Mapnik LOG> 2020-05-01 12:20:17: SVG PARSING ERROR:"SVG support error: <font-variant> attribute is not supported"
Mapnik LOG> 2020-05-01 12:20:17: SVG PARSING ERROR:"SVG support error: <font-weight> attribute is not supported
NOTICE:  identifier "right_temps_perdu_moyen_par_jour_supplementaire_en_heure_de_pointe" will be truncated to "right_temps_perdu_moyen_par_jour_supplementaire_en_heure_de_poi"
NOTICE:  identifier "right_temps_perdu_moyen_par_jour_supplementaire_en_heure_de_pointe" will be truncated to "right_temps_perdu_moyen_par_jour_supplementaire_en_heure_de_poi"
NOTICE:  identifier "right_do_any_hospitals_have_access_to_a_tax_refund_offset_program_in" will be truncated to "right_do_any_hospitals_have_access_to_a_tax_refund_offset_progr"
NOTICE:  identifier "right_do_any_hospitals_have_access_to_a_tax_refund_offset_program_in" will be truncated to "right_do_any_hospitals_have_access_to_a_tax_refund_offset_progr"
WARNING:  ST_Shift_Longitude signature was deprecated in 2.2.0. Please use ST_ShiftLongitude
WARNING:  ST_Shift_Longitude signature was deprecated in 2.2.0. Please use ST_ShiftLongitude

We've never done anything with them, wondering how useful are they and what approach we should give to them.

[dgaubert]

Also wondering why some of them have the prefix Mapnik LOG> {TIMESTAMP} and if they can be omitted by setting a higher security level.

[Algunenano]

@Algunenano, do you know what severity level we are setting for the logger while compiling @carto/mapnik?

We don't change it https://github.com/CartoDB/mason/blob/master/scripts/mapnik/3.0.15-carto/script.sh so whatever is default.

The log level is defined at compile time, and when it's not defined it's automatically set to 2 (https://github.com/CartoDB/mapnik/blob/1021a5e3059e939ffc78b84792e605ae6fd8344c/src/debug.cpp#L41) which enables logger::error.

The SVG PARSING ERROR messages are reported by the svg_parser.

The logs starting from WARNING or NOTICE come from the database and don't have the mapnik log format (they should start with Mapnik LOG>), so they are either printed without the logs (I couldn't find them) or they are printed directly by libpq for some reason. I would need to investigate further to find where they are being emited.