Feature Request: use OWS Context (an "external" WPS process description)

[cehbrecht]

Description

The OGC OWS Context can be used to describe a WPS process. The WPS process description would then be independent of the WPS service implementation. A processing tool could be bundled with its WPS process description (OWS Context document) and picked up by a any WPS service which is able to read OWS Context documents. Processes would become plugins with a plugin description which can be used by different WPS serivces without changes.

Steps to Reproduce

Additional Information

• Earth Observation (EO) Cloud Processing Hackathon using an "Application Package"
• OGC Testbed-13 Application Package using OWS Context

[huard]

Will this facilitate the translation of service description to other languages ? Issue #64

[cehbrecht]

@huard
To be honest I haven't looked deeply in the OWSContext. My understanding of it comes from the talks with Tom.

In the testbed they have the example of a dockerized application which is executed by a WPS service. The application uses on OWSContext document for its description (inputs/outputs). The container is executed like a command line script with defined inputs ... outputs are collected afterwards. So, the WPS service can call anything ... it is just a command-line script.

Don't know how the logging and status information (progress) is handled.

[tomLandry]

This will be one of the first things we'll design. As DKRZ, Ouranos and Tom Kralidis are TB-14 observers, I expect the information will make its way pretty nicely. I'll still have to double-check with OGC. David Byrns will probably lead the design, with my help. Kick off was awesome by the way!

[allixender]

Hi all,
I have been working with OWSContext/OWC for a while now, but in with Scala/Play Framework and TypeScript/Angular (https://github.com/ZGIS/smart-owc-geojson and )

I started in a project where we also aim to evaluate SensorML2 vs WPS XML vs OWC as complex process descriptions for something like environmental models. So far we are lacking useful real-world implementation of a WPS to do that. I used a similar approach some time back with WMC and 52N WPS but that was only some hard-coded mess from my side.

I am keen to contribute, because I won't build a WPS in Scala from scratch any time soon, but the 52N Java Servlet implementation is not my favourite either. I had great experiences with Tom Kralidis and PyCSW so I might as well just stcik eith Python and give PyWPS a shot. I am at the Univisersity of Tartu, and we are not yet OGC members but I am bringing this on the way. We have seen some issues with the definitiuons of OWC Geojson Encoding but couldn't really bring them towards the OGC working group for OWC (https://allixender.blogspot.co.at/2017/07/ogc-ows-geojson.html and ZGIS/smart-owc-geojson#4).

Happy to pick that up with you guys, if possible.

How shall we get started?

[jachym]

Hi, OWC seems something we need to support and seems to bring the (at least to me) important topic "containerization" of running jobs.

@allixender I think, if you are interested in this topic, try please to have a look at waht @lazaa32 is doing with docker support, that could be one of the ways.

And if I understand correctly, we need also OWC parser class (which should be implemeted in OWSLib imho).

PyWPS/pycsw/OWSLib are sibling projects, if you like the one, you should not have problem with the other.

But having real-world WPS implementations is hard. I thing @cehbrecht has some really good working. I would be happy to help with deployment of some others.

[allixender]

Hi, yes seems to make sense to implement OWC encodings (@tomkralidis AtomXML and? OWC GeoJSON in OWClib first). Yes, I'll look it up.

[allixender]

I created a ticket in OWSlib to implement the OWS Context types, which then could be used here in PyWPS: Implement OGC OWS Context format geopython/OWSLib#441 ... and implemented most fields geopython/OWSLib#483

[tomLandry]

Link to public code repository from EOC hackathon: https://github.com/opengeospatial/EOEPHackathon2018

[christophenoel]

Hello,

Could you please provide you view about why the WPS process description would be independent of the WPS service implementation ? I don't understand this point.

The WPS already defines a nice standard for defining the Process interface which is that Process Description. Why don't you put the OWS Context inside the existing Process Description ?

Also, OWS Context is not (especially) written to describe inputs/outputs, so did you define a standard for defining such interface ? What is the advantage of creating an additional specification to the existing Process Description ?

Thanks a lot in advance for the clarification(s).
Christophe Noel.

[tomLandry]

Hello @spacebel. Are your question formulated to the implementer @allixender? As for myself, I only pointed out this timely work to the OGC testbed, and vice-versa. I'd like to try out the implementation and I welcome clarifications and contextualisation!

[christophenoel]

Hello Tom, all answers are welcome :) I try to understand the approach. Thanks !