[gdal-dev] vsicurl configuration design decisions

[Frank Warmerdam]

Sean,

The obvious answer is that interfaces that are organized around the
dataset name do not make it easy to transport other parameters in a
way that is specific to one dataset.

While I worry a bit about complex dataset syntaxes I do think there is
a power to embedding these options in the dataset name.  I sometimes
wish we had a more generalized way of wrapping options into dataset
names with clear escaping rules, and a way to avoid interference
between different levels of wrapping and virtualization.

I would add that I requested a mechanism to control /vsicurl/ retry
strategies as we this machinery widely and failure to do "normal
retries" in /vsicurl was a problem for us.

Best regards,
Frank


On Mon, Oct 9, 2017 at 7:18 PM, Sean Gillies <sean at mapbox.com> wrote:
> Hi all,
>
> It's written in
> http://gdal.org/gdal_virtual_file_systems.html#gdal_virtual_file_systems_vsicurl:
>
>> Starting with GDAL 2.3, options can be passed in the filename with the
>> following syntax: /vsicurl/option1=val1[,optionN=valN]*,url=http://...
>
> I'd like to discuss the design decisions that are being made here before
> this gets out into the world.
>
> I'm uncomfortable with the way configuration is spread between environment
> variables, config options that surface in the API, and also in identifiers.
> I don't think it's a great idea to that expand the amount of configuration
> in dataset identifiers. It's redundant, the syntax is complicated, and it
> dilutes the network effects of reusing identifiers in our applications.
>
> Are there specific advantages to this
>
>   ogrinfo -so /vsicurl/max_retry=10,url=https://example.com/poly.shp
>
> that we can't also have with a curl-style
>
>   ogrinfo -so --max-retry=10 /vsicurl/https://example.com/poly.shp
>
> or, better yet, in my opinion
>
>   ogrinfo -so --max-retry=10 https://example.com/poly.shp
>
> on the command line?
>
> --
> Sean Gillies
>
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